TDi is a great engine. It’s so much lighter than a 4bt. Plus a mild upgrade gets you over 500lb/ft of torque. You can miserly idle around in a tdi on trails and barely use any fuel.
@@DirtRoadTherapy I mean exactly what you said. Nate ditched the stock tank for this puny little air compressor looking tank, because it burns so little fuel, he didn't need to carry such a large tank
We had two TDI Jettas and loved them. On both TDi engines the harness that goes to the glow plugs would fail. There was a replacement harness that we had to get for them that fixed the issue with one or multiple glow plugs not working. Plugs were fine, harness wasn't.
I swapped a '95 cherokee 4.0 into my 84 cj7. Had to create a custom hole and mount for the crankshaft position sensor in the T5 transmission bellhousing. Last year, it started running badly when cold, but great after 10 mins of warm up. Turned out that one of the transmission to engine bolts that also held the crankshaft position sensor bracket in place had loosened up so the CPS would be too far away (must have been just barely) during part of the engine's rotation. So the computer would shut off the ignition and turn it on again and again until it warmed up enough to close that gap due to the metal warming up and expanding. Not sure if that in any way relates to your issue, but there you go. Thanks for the good info and content.
So with a overspeed scenario, you get contact between the exhaust valve and the piston because the piston is moving faster then the exhaust valve can close. Because of valve float like you mentioned. With the whole cold start problems, I'm not sure. Maybe an exhaust valve barley made contact and put a slight bend in it. But with temperatures rising things expand and the valve seat expands enough to seal the exhaust valves again. Again big maybe. But to find out you can pull injectors and bore scope the engine to inspect the top of the pistons. Just an idea from a cat dealer tech.
I remember when my VW Rabbit had diesel-run away. It idled to 6k, and when I pulled over to turn off my vehicle, but it kept running. My buddy and I got out as quickly as we could before it blew up. With the key out, it ran for a minute or better. I was lucky nothing happened.
When describing the diesel engine operation at the beginning of the video you really glossed over the most important part of what makes a diesel a diesel. And that is the compression ratio when the piston comes up and compresses the air. Compressed air gets very hot and that heat is what ignites the fuel from the injector even as it's being injected. This is why the injector correlates so well in comparison to the spark plug. Also despite knowing your issue is throttle control related you might want to double check crankcase breather location and make sure different vehicle angles can't allow oil to be sucked into the intake. Diesels run quite well on hot engine oils.
I am wondering if the overspeed damaged a glow plug, which now results in the hard cold starting. As I recall the TDI uses a glow plug with a sensor built into it. So perhaps its on the sensor side of one of them.
The only reason I have a hard time jumping on board of agreement with this comment is the AlH in my mk2 that I have on my channel has no glow plugs and starts perfectly fine cold or hot so to me the glow plugs have little effect unless you're somewhere it's 20 degrees (I'm in Washington state so it's cold here early in the mornings already and still first click not a full revolution and it's idling away)
In my experience of diesel run away I had a 550 hp Cat in my rig. I dumped a gallon of antifreeze in the air intake within about a minute. Saved the engine. I have seen others go about 30-45 minutes before the engine blows
Intercooler hose blew off because the TDI has a “throttle plate” that’s used to prevent exactly this situation from being a total runaway. When you turn off the ECU it shuts the throttle and no runaway. All your boost probably slammed into that, and with no blow off valve, it found a way out.
Had 1985 Peterbuilt semi with a two stroke Detroit 8v92 run away on me before and had to stuff my work coat in the intake to shut it off. The seals in the turbo went bad causing the run away, my dad who was a mechanic at the same company rebuilt the engine and I drove the truck another ten year's before the company retired those trucks, it was still my favorite truck.
I used to work on “jimmies”… two turbos leading into twin 671 superchargers on a big Cummins truck. The drive shaft on the superchargers shears so the turbos blow tons of air input two unlimited super chargers, which kick out more exhaust…into turbos, more pressure into the superchargers… rinse and repeat. Fun to watch, not so great to deal with. The damper slammed shut too late and suck most of the input stuff into the blowers… lots of black smoke and noise.
My 4d55 mitsu had similar situation, throttle stuck wide open, sat on governor for around 10 second,I believe I flattened my cam a little, maybe stretched a timing belt a little
I would say it’s a compression issue if it goes away once it gets warm , tolerances tighten as it expands improving compression which leads me to think your valves are ok but you have a bad piston I would start with a compression test injector cut out test, a damaged glow plug can cause some pretty funky issues if they are sensored even check that the turbo isn’t leaking oil into the intake Hope any of that can help Keep up the great content!
Hey Nate, I remember watching that episode. I blew my head gasket that same day and was bummed for the both of us. Fortunately you had seemed to have escaped without much harm, but now it seems there are some lingering issues. Well, not long after I replaced my head gasket I made an attempt to drive up to Seattle from southern California (without much shakedown time). I was trying to push my land rover 200Tdi up over the pass from santa clarita in fourth gear at about 2900 rpm, which I thought was a safe max, considering EGTs were below 1200 f, while oil pressure and engine temps were also good. The engine seized and couldn't be restarted until it cooled for about 10 minutes. When it did start it ran rough, but I was able to drive it off of I5. When I examined the engine, I found that the pcv was now highly pressurized indicating blowby. This is my first suggestion to you is to check for blowby, by removing the oil filler cap or the pcv hose and checking to see if you detect any extra pressure. I hoped that I had blown the head gasket again or maybe the valve lash was off on one of the cylinders. Well, I pulled the head off and found that one of my cylinders was badly scored. What I surmise is that this piston had expanded enough to cause the engine to seize and the cylinder wall to become scored. Why I suspect you might have the same problem is that I have similar symptoms to what you are experiencing (but to a more extreme degree). It is very hard to start it cold and it smokes like crazy, but when it warms after about ten minutes, the smoke is much reduced and the rover becomes driveable -- to the point of almost being normal, but still somewhat smokey. I decided to add Restore Engine Restorer to my oil to see if I could regain some of my lost compression and this is what I found: The engine starts instantly, but runs really rough and smokes heavily for about ten seconds, then moderately rough with moderate smoke for about 30 seconds. Then it suddenly returns to almost normal, with absolutely no smoke, and I can drive it quite normally. I really hope you don't have the same problem as I do since I will need to do e rebuild, but the issues do seem similar. I don't know exactly which modifications you performed to your fuel system. I modified my injector pump a bit. I added some spacers to the governor spring and added a timing-advance spacer. I also optimized lift at TDC. These modifications, I think, allowed me to push the engine beyond the safe limits. My 200Tdi will need new cylinder liners and rings before I can get it back to being a daily driver, but I am happy I can drive it under its own power from time to time, and I wanted to rebuild it anyway (but not just yet!). As others have suggested, compression and leakdown tests will help diagnose your issue.
We had a runaway on a preparer stroke 6.9 ford diesel the first 6.9's had head gasket problems I worked at a ford dealer someone brought a van in with blown motor they had put a Turbo on it and the head gasket blew and it ran away on antifreeze. Ford was so dedicated to good experience at this point they warranted it.
Love the content bro! as for the TDI, compression test will tell you a lot. if its low on a cylinder or two, pull the oil pan and check the rods, I've heard of TDIs slightly bending a rod or 2 in turn creating a shorter stoke, lower compression, and no combustion... at cold temps you'll have a temporarily dead cylinder till it warms up. I wouldn't start with checking the rods... obviously check your valvetrain first if your comp test comes back low. keep up the good work and good luck with the troubleshooting!
Does sound like a compression type issue. Easiest way to locate the failed cylinder is a laser temp thermometer on start up. Check the cylinders to see which one is the coldest and start diagnosing that cylinder from there. Could be a failed injector over squirting or no enough. But sounds more like a leak from a valve or a injector cup from too much boost. Love your content brother!
I would do a compression test and check my balance rates on the injectors, while I have an oil sample out for analysis as well. My Cummins ran similar to that cold when one of the injectors built up a deposit that prevented it from sealing up, but then it ran fine warm. However an oil analysis discovered fuel dilution in the oil. I was fortunate in I sent my oil sample in early so my fuel dilution didn't get to a dangerous point. After doing an injector set it was back to 100% normal.
I would check the oil pump chain tensioners. It might have gotten starved of oil. Which would give you blow by until it warms up. VW stopped making the tensioners and switched to a gear setup that costs 2500. I had to get my tensioners from London on EBAY. Good luck.
Like almost everyone is saying, compression test. Do one cold, and then after the engine warms up. Direct injection diesel's can be hurt by prolonged or frequent idling as they will not get warm enough to seal the rings properly at idle temperatures.
It happened to me in my big rig. Cummins engine ran away, wouldn't shut off. Pulled off air intake filter and stuffed my backpack in there. The amount of smoke spewing out of exhaust was amazing. 😂 Was quite a scene in LA Traffic. Everyone thought my rig was on fire.
My alh samurai had what I thought was pedal to ecu issues. Plugged in vcds and it was communicating. Turned out injection pump was on its way out. Verified this on the tdi injection timing graph. It was off the chart.
My 2000 Jetta alh pops and farts when it’s cold too. When it’s warm it runs awesome. It also has a bad maf sensor so I definitely didn’t over rev it. I’ve seen in your newer video on this engine that it’s a bent con rod. I hope that’s not my problem. Anyways I’m new. Love the channel. Subbed!
glow plug would be my first guess, one may not be working properly causing the roughness at ambient temperature and clearing up as the entire engine warms up to operating temp.. My second guess would either be a piston ring or injector because of that sudden boom when you turned the ignition off, all that pressure from wot to engine off had to go somewhere.
Only time I've seen one run away in person was on a 2 stroke Detroit 6-71, normally, in a marine application they have air dampers in the intake that you can close...this one didn't so we threw a trash bag over the filter and it eventually killed it, that thing was screaming at about 4k RPMs
Are you getting a ton of blow by at cold start? I've seen where a cracked piston or cracked compression ring will make it run like that at cold start. I had a cracked piston, engine ran but something wasn't right, it run a little weird at cold start but ran fine-ish once it warmed up. I ran an injector test and it kept saying #4 was almost out of tolerance and after further inspection I just changed the injector, but still ran the same. I later found out that I had a cracked piston. I would definitely do the compression check.
I would definitely start with a compression test just to confirm that your cylinders have good compression low compression will definitely cause a cold starting issue and would also haze like that out of the exhaust on start up until warm
Cold start issue is likely related to valve contact. A few valves are likely bent and they seal up better when the engine is warm. I had a Honda do the same thing. Adjusted the valves and the misfire when cold went away. You should definitely do a compression test, and likely a cylinder leakdown test on any holes with low compression. I have been a diesel mechanic for the past ten years and automotive for seven before that.
I say doing a leak-down/compression test with the engine cold and again with it hot. Look for a large variance in one of the cylinders when cold since the problem seems to go away once it's warmed up. If you don't fine anything then maybe it could be the injector or a glow plug. I've never worked on a diesel, but if one cylinder isn't way out when cold and assuming all cylinders are within spec when hot, then it must be fuel delivery or possibly a glow plug since it only happens when cold. Not sure if the glow plugs remain on for a while after it starts while the engine is cold, or only when starting. If you have a spare plug and injector, maybe swap them into each cylinder sequentially if the leak-down/compression test looks normal.
Seal in the turbo? Do you have any crankcase ventilation back to the intake, started sucking crankcase oil? But why did it shut off with the key if that was happening.
Mate, I don't care what you do, drive, build or even work on the Landrover you are entertaining. My thoughts on your problem, it's a VW motor ;-)haha but I look forward to the rebuild cheers
Nate. Considered fitting a pop-off valve ? This ensures when the turbo is boosting, it can be manually set at say 19psi, so over-boost is vented to atmosphere ! V.
Nate, many Bosch diesel injection pumps advance fuel timing for cold start. Probably uses intake temp sensor. If anything prevents this slight advance in timing on cold startup. Chug chug smoke. Sometimes thinga are coincidence, I don't think your bad startup is related to your momentary rev. Chase this cold start fuel timing idea down. I had a 6bt act up when a single wire got disconnected on the back of the pump.
I had this happen to my 2002 jetta TDI.. seals in the turbo went out and pumped oil straight into the intake. tach pegged out at 5k, and i tried dumping the clutch in 4th and standing on the brakes. before i got on the brakes it did a nasty burnout, then once on the brakes it slipped past my clutch and threw rod number 3 threw the block and bent the other 3.
@@DirtLifestyle haha im sure it was for everyone else at the intersection. now it has a VNT17 turbo, 1019 injectors, 3 bar map, and a stage 4 malone tune. so in the end, i got a car thats WAYY more fun to drive and still gets 43 mpgs driving it like a race car.
Had this twice with 1980 VW Rabbit 1.6 TD .. once from PCV back feeding oil to the intake when the engine was worn .. rebuilt the engine, but should have replaced the turbo, next time was turbo seal .. Pistons hit the valves at 6000 rpm before I could stall it, it still ran fine with valve inprints in the piston tops .. Sold the Rabbit after the second time, told the new owner to get a new turbo or it would do it again😓
@@Oz4me_craig ooof. I should have seen mine coming. The day it blew up, it bounced limiter at a red light and came down right away. But I drove it again without looking into it. And it ran away. That was also maybe a year into owning it.
if you want to go minimal effort - Try the old seafoam in the crankcase oil trick see if it loosens anything up that's sticking when cold. Some good comments below ref heater plugs and intake cracks.
I was in a large industrial ammonia leak (refrigeration) and the warehouse guys made the truckers shut off their engines before evacuating. Apparently ammonia in the intake of a diesel can make it run away.
@@DirtLifestyle now that I watched the video I thought the same might be an injection issues u have maybe one inyector is getting stuck when u start it cold, I'm not a mechanic but those are my thoughts.
Intercooler and hoses was full of oil. Extreme angle of climb sucked oil into intake. Engine ran on. You turned key off and throttle plate closed as it should to avoid run on. Now you need to check for damage. Do compression test and cyl leak down test.
Im no diesel specialist but Michael Cox from Bronco factory does injector cleaning. Maybe injector clean and a fresh set of glow plugs will make it run better
I'd say start with a compression test, then drill out an old glowplug to make an adapter to do a leakdown test, that would give you some indication of piston or valve damage.
Did your diesel guy check for a bent push tube ( push rod). usually on larger diesel engines the valve s and rockers will survive some contact with the piston. have seen quite a few bent push tubes. If you have a way to do acylinder leak down test, you can hear if a valve is bent because the air will escape past the bent valve and you should hear it.
Take a look at your turbo, overboost or turbine wheel over speed can cause some similar issues. Also wouldnt hurt to look at some live data on your injectors to make sure they are OK. Make sure the balance rates are within spec.
In my country i have tons off tdi it 300h to 500+ hp and cold start problems it's almost always hydraulic valve lifter our piston rings, but i think it's the lifters, Ina black makes very good valve lifters
I have no idea about diesel engines, but do need to say something. Of most importance, you sir, have grown, not only in your content, but also your delivery. I know you left your other job to pursue a new path but you, IMHO, have exceeded the limits of YT. Yes, subscribership will continue to increase, but believe you can provide so much more to so many more! Second, did you really threaten that fly?!? 😛 Stay safe out there and First Class Thumbs Up!
I've had a diesel runaway before but it was a mechanical pump we had to choke it out by stopping airflow. I had never heard a diesel backfire before til that clip. Seems like it's possible it slightly damaged a valve/seat. I've had cracked valve seats cause performance issues while cold, then seal up as the engine warms up. BUT I do not claim to be an expert, just my dos centavos. Love your diy/education content btw. Probably moreso than the wheeling.
@@DirtLifestyle that's true too. I don't know VW well at all. Well... Looks like you got your work cut out for you. Heh sorry. Look forward to hearing about the official prognosis, etc!
Glad it's still running, but yea I feel like it could be anything you said, without doing at least a compression/ leak down test. Cooked something electrical? Damaged valve? A combo? I don't know much about diesel, but I saw a motorcycle's throttle get stuck open, and the bike wouldn't start or idle, until hot, ever again.
I suspect a bent valve. Try a leak down test on each cylinder with all valves “closed” haha. Struggling to imagine how 4-5k rpm would damage an injector. And the smoke was instantly white at the Moab incident. I think an injector failure would be more gradual than that. Keep us posted! This one’s tough to figure out!
Best way to stop a run away diesel if you cant yank the intake tube off to choke it out. Is to take your fire extinguisher and clog up your air filter to choke out the air flow to kill it. The only worry u have then is cleaning out your airbox and replacing your air filter. That's what we had to do on one of our n14 cummins powered semi trucks.
I'm a big fan of starting with the easy stuff first. Glow Plug Injector Compression In that order would probably be the easiest to troubleshoot. If low compression, a borescope may give you some hints.
This is why I warned you about the CRD Liberty. Mine ate a cam sensor and after that it was nightmare city… definitely glow plug related, they were infamous for that. They had Bosch glow plugs and controllers, I bet your TDI does too. Electronic crap is the worst, I’d rather have something broken I can see.
From my experience it seems that you have some valves not seating properly possibly bent. Once your engine warms up to running temperature the valves are seating properly. I’ve seen this on 5.9 Cummins some catipillar and 6.2 GM diesels during my military service in which a head rebuild fixed the problem. Check your turbo out also. I’ve also seen worn seals and even cracks that are easily missed during disassembly cause a similar problem from an over boost.
Wish there was an easy way to get a peek at the valves with a bore scope. But without a spark plug hole, pulling the injectors would kill two birds: inspect injectors for damage and bore scope the pistons and valves. But, if the camera angle is not conducive to see it all you’ll still have to pull intake or exhaust. Haven’t done a leak down on diesel -only deal with gas. But that normally tells me if it’s intake, exhaust or rings by where the air goes. That said, bad is bad and doesn’t normally fix itself as the engine warms up. Unless it’s a lifter (gas fueled reference) finally joining the party after pumping up. And it will get worse if ignored. What made the pop-off noise and smoke under the engine during the Moab shut down? Was that steam from the overflow or radiator? Could something (overheat) have damaged the wiring or t-stat so it runs crappy when cold due to not enough fuel?
Glad to see the TJ is back but I think many of us still have questions unrelated to the engine. Still curious on the front axle situation and what happened to the sticky tires though. Since you're one the trend setters for smaller axles and big tires, it seems like a huge shame that you broke two axle shafts, swapped tires, and left us hanging on what's really going on with that.
Probably, it is a series of issues and circumstances rather than a single source fault. Each on their own wouldn't do too much, but under the circumstances at the time, they compounded to cause the runaway. It does certainly sound like there is a throttle issue so that would be one rabbit hole to start chasing down. You had mentioned the condition of your turbo too, and I strongly suspect it is the source of the oil that fed the runaway. Adding in the vehicle dynamics of getting in, and out of that hole would have shifted the fluids considerably, and to enough of a degree that it fed more oil to a hot, revving engine's intake, and it took off on you. Without at least the three factors of turbo, throttle, and vehicle dynamics, I don't think it would ever have come to that point. It's more work, but I think you will find multiple smaller issues, rather than a single "Eureka" source. Looking forward to hearing what you find Nate, good luck!
I have had 22R and 22R-E's that did this. They had very low compression, ran great when warm. You prolly fried some piston rings, or they did not get proper oiling while at the angles in the tub, that would cause the rings to over heat and fry. Do yourself a favor and get a OM617 much easier to work on, and a lot tougher of an engine.
They are heavy and kinda gutless. Have not seen any of the gladiator episodes. The strength of the OM617 is in the lower end. Stock they are 125hp and 181 ftlbs so weak. Popular to mod in Europe, $2000 dollar swedish fuel system and a bigger turbo solves it. The lower end is rated for 400hp. So stock they are dogs, but modded they can be beastly.
The PD engine is in my opinion the best engine VAG have ever produced, ultimately strong and reliable. Looking back at the video of the fault it doesn't look like a 'run on' as you say (it would be reving a lot higher if it was) definitely a throttle pedal issue. I was a VW technician during the run of the 1.9 PD engine and seen a few run aways, after cleaning out the intercooler and pipes, fixing the cause.. usually turbo failure they run mint. Looking at the exhaust smoke in the video it looks like there is a constant 'puff' of smoke indicating a possible missfire. My first go to would be an injector, unfortunately with the injectors being inside the head it's not so easy to just unplug one and find the culprit. My first way to go would be to use a stethoscope on the side of the head next to each injector, maybe you will hear something that sounds different to the rest?? Other than that it would be cutting the injector electronic feed somewhere in the loom one by one and seeing where the missfire lies... Good luck dude 😬😬😬
throttle position sensor maybe it's bad and now it's slightly "pressed" giving to much fuel till its warm? could have carbon build up on valves and they aren't seating right losing compression. till they heat up and get just big enough to seal?
The throttle position sensor is the accelerator pedal with this type of diesel believe it or not lol. And it definitely was a problem but not the current problem. But a theory though
I think a compression test would be a good start. Could be any component that swells and seals with heat. If it’s rings, you’ll know with a test. If it’s a turbo, I suppose you could do some sort of vacuum test with soapy wooder on the charge pipes
Compression/leak-down should narrow it down. I was thinking rings because of autocorrect when heated. I think a cracked skirt would present different. If your friend is a TDI mech then I’m sure he checked the pulse and flow on injectors. It doesn’t sound pressure related either. Good luck. Looking forward to finding out what it is when you find it.
Sounds like wore rings. Low compression till it warms up and takes up the space. Also blue smoke means burning oil so that also leads me to believe wore or or broke ring land. Run a compression leak down test
I am not a diesel specialist, but it seems to me like a valve-related issue, possibly a bent or tulupped valve letting just enough compression by to make a funky cold start till things can warm up and expand to lock in the compression. probably an issue to fix in the long term but at this point drive it till winter. But a cold leak-down test will probably tell you what you need to know.
I dont know much about vw how ever I had a similar cold start issue that I ended up rectifying by putting a new glow plug relay in never had the issue again
First thing I would do is a compression test - then hook up the scan tool and see what my injector balance rates look like when it is cold - that will tell you if one cylinder is adding or pulling back fuel. A bad glow plug will throw a fault code on that engine and it should throw a cylinder contribution fault code as well if an injector is not fueling correctly.
Most common true run away is from the engine using its own oil as fuel. Usually over the piston rings or from a oil soaked intercooler. For emission reason the will vent the crankcase into the intake often before the intercooler. I've seen mechanical pumps "run away" as in you can't control them but as long as the internal govoner is operational properly it doesn't cause damage. Is short if you can turn off a key and the engine stops its not run away. You just can't control the throttle.
I know someone who had a ALH runaway for 20 minutes. He thought it would explode it was revving so high. He added oil and it started back up without any damage. I suspect you have a dirty sensor from running dirty on the overspeed event.
I'm not as familiar with the vw tdi but I do know that some of the latter ones had cam operated injectors that were electrically metered and they could be damaged by an over rev
Love the video! I was wondering what was going on with it. Please please do a 1st gen 4Runner build? 86-89 hopefully 22re ifs for something different then your normal solid axel builds
Make sure your oil level isn't going down. Could be filling the cylinder with oil as it sits and burning it out as it warms up. Someone with a scan tool should be able to shut down each injector one at a time. Maybe if you can do this while it's cold you can find a weak inejector. That or an injector itself could be leaking down and dumping raw fuel as it sits. Not sure if it's the same engine in the forklifts I work on (linde forklifts used to use vw engines) but we've also seen the fuel rail pressure sensor (on the crank side of the rail) cause a leakdown (loss of prime) causing extended starts but not rough running conditions. Also I don't know what temp you're starting it at but glow plugs could also be a slight possibility but you'd probably get a code for that.
I would say you have nicked a valve to piston . While the cam was out did anyone check the installed height of the valves cold ? A slightly bent valve can seal hot better than cold as everything grows hot . The longer you run it the better it will run if that is the case the valve will slowly straiten out until it breaks .
Since we have quite a few of these diesels over here... I guess that you have a faulty injector, glowplugs really don't do much in warmer ambient temperatures and even if it would run just fine but needs a few more seconds cranking. Check compression, faulty injectors often cause temperature problems that can lead to severe damage.
First, I don't know what the problem is. When addressing engine health issues I always first do a leak-down test on each cylinder. This will tell if there is a problem and begin to pinpoint where the problem is. You can detect each one of the following: a leaking head gasket, leaky intake valves, leaky exhaust valves, and leaky rings. Then inspect the turbo. An oil leak in the turbo is the most common runaway scenario now that most are not mechanically injected. Since you may have solved the runaway problem with the new throttle sender, it may be a long shot though. Since refurbished TDI injectors are about $300 a set I won't recommend just changing them, but I'd lean toward a weak injector, not functioning well when cold.
Does it usually smoke that bad or was it getting oil into the combustion chamber past the rings at that angle? I'd check compression to make sure you didn't bend a rod from oil getting past the rings. That would cause it to run bad when cold and get better when it warms up.
are injectors for the tdi expensive? might be an easy way to find out by just replacing them, or if you have enough time, send them off to be cleaned and tested.
Have you done all the typical upkeep maintenance on it since? Oil change, fuel filter, injector cleaner/fuel system flush, cleaned intake piping etc? And is the throttle pedal code cleared and staying clear? It definitely seems like there’s a fuel burn issue (something mechanical) but if the electronics aren’t happy, I’d definitely look to remedy that first. I know on the ALH the cold start cycle messes with injection quantity, so that could certainly be part of the issue your seeing with fueling. Looking forward to more content with the TJ and even more so to the eventual resolution here!
I don't know much on vw diesels but is this one have glow plugs take a ohmmeter a measure the resistance when cold in the plugs and then afterwards when hot and compare the resistance the lower resistance is the cilinder on low compression engine must be running
So engine over speed can damage a number of things. But I’d check the turbo. As a hundred RPM loaded overspeed can be 1000s in shaft speed RPM, if it’s worn the bearing it could be ingesting oil until it warms up.
Hey bro. Injectors are rated for a certain compresión and speed. So they are rated. They may have gotten messed up because of the over speed. No for the pedal issue. It could have been the angle causing a short in the harness making the engine go crazy. You should be able to do an overlay to the ECM just need to know the wires that go to it. I watch you’re videos all the time. Great stuff.
TDi is a great engine. It’s so much lighter than a 4bt. Plus a mild upgrade gets you over 500lb/ft of torque. You can miserly idle around in a tdi on trails and barely use any fuel.
With my TDI, I use 1/8th the fuel on the trail as my gas engine buddies no exaggeration!
@@DirtRoadTherapy I mean exactly what you said. Nate ditched the stock tank for this puny little air compressor looking tank, because it burns so little fuel, he didn't need to carry such a large tank
Is there an easy to adapt automatic? Would love a diesel but only adapter I can find are manual
So glad to see some TJ content. This is the build that’s completely inspired me in my build.
We had two TDI Jettas and loved them. On both TDi engines the harness that goes to the glow plugs would fail. There was a replacement harness that we had to get for them that fixed the issue with one or multiple glow plugs not working. Plugs were fine, harness wasn't.
I swapped a '95 cherokee 4.0 into my 84 cj7. Had to create a custom hole and mount for the crankshaft position sensor in the T5 transmission bellhousing. Last year, it started running badly when cold, but great after 10 mins of warm up. Turned out that one of the transmission to engine bolts that also held the crankshaft position sensor bracket in place had loosened up so the CPS would be too far away (must have been just barely) during part of the engine's rotation. So the computer would shut off the ignition and turn it on again and again until it warmed up enough to close that gap due to the metal warming up and expanding. Not sure if that in any way relates to your issue, but there you go. Thanks for the good info and content.
So with a overspeed scenario, you get contact between the exhaust valve and the piston because the piston is moving faster then the exhaust valve can close. Because of valve float like you mentioned. With the whole cold start problems, I'm not sure. Maybe an exhaust valve barley made contact and put a slight bend in it. But with temperatures rising things expand and the valve seat expands enough to seal the exhaust valves again. Again big maybe. But to find out you can pull injectors and bore scope the engine to inspect the top of the pistons. Just an idea from a cat dealer tech.
Would 100% drop a bore scope in there, regardless of theories. Might show nothing, might be very enlightening.
I remember when my VW Rabbit had diesel-run away. It idled to 6k, and when I pulled over to turn off my vehicle, but it kept running. My buddy and I got out as quickly as we could before it blew up. With the key out, it ran for a minute or better. I was lucky nothing happened.
When describing the diesel engine operation at the beginning of the video you really glossed over the most important part of what makes a diesel a diesel. And that is the compression ratio when the piston comes up and compresses the air. Compressed air gets very hot and that heat is what ignites the fuel from the injector even as it's being injected. This is why the injector correlates so well in comparison to the spark plug.
Also despite knowing your issue is throttle control related you might want to double check crankcase breather location and make sure different vehicle angles can't allow oil to be sucked into the intake. Diesels run quite well on hot engine oils.
They also run really well on hot transmission fluid. Definitely agree with the crankcase breather.
I am wondering if the overspeed damaged a glow plug, which now results in the hard cold starting. As I recall the TDI uses a glow plug with a sensor built into it. So perhaps its on the sensor side of one of them.
You are the second person to suggest this and it actually makes pretty good sense 🤔
That makes a lot of sense.
If it goes away after warming up then that would be my opinion as well.
The only reason I have a hard time jumping on board of agreement with this comment is the AlH in my mk2 that I have on my channel has no glow plugs and starts perfectly fine cold or hot so to me the glow plugs have little effect unless you're somewhere it's 20 degrees (I'm in Washington state so it's cold here early in the mornings already and still first click not a full revolution and it's idling away)
@@AverageJoeBuilds His TJ has an '06 TDI though, so it has the sensors built into the glow plugs.
In my experience of diesel run away I had a 550 hp Cat in my rig. I dumped a gallon of antifreeze in the air intake within about a minute. Saved the engine. I have seen others go about 30-45 minutes before the engine blows
Intercooler hose blew off because the TDI has a “throttle plate” that’s used to prevent exactly this situation from being a total runaway. When you turn off the ECU it shuts the throttle and no runaway. All your boost probably slammed into that, and with no blow off valve, it found a way out.
Had 1985 Peterbuilt semi with a two stroke Detroit 8v92 run away on me before and had to stuff my work coat in the intake to shut it off. The seals in the turbo went bad causing the run away, my dad who was a mechanic at the same company rebuilt the engine and I drove the truck another ten year's before the company retired those trucks, it was still my favorite truck.
I used to work on “jimmies”… two turbos leading into twin 671 superchargers on a big Cummins truck. The drive shaft on the superchargers shears so the turbos blow tons of air input two unlimited super chargers, which kick out more exhaust…into turbos, more pressure into the superchargers… rinse and repeat. Fun to watch, not so great to deal with. The damper slammed shut too late and suck most of the input stuff into the blowers… lots of black smoke and noise.
My 4d55 mitsu had similar situation, throttle stuck wide open, sat on governor for around 10 second,I believe I flattened my cam a little, maybe stretched a timing belt a little
I would say it’s a compression issue if it goes away once it gets warm , tolerances tighten as it expands improving compression which leads me to think your valves are ok but you have a bad piston
I would start with a compression test injector cut out test, a damaged glow plug can cause some pretty funky issues if they are sensored even check that the turbo isn’t leaking oil into the intake
Hope any of that can help
Keep up the great content!
Check for cyld missfire code, swap injectors between cylinders and note if missfire code moves with injector or stays on original cyld
Hey Nate, I remember watching that episode. I blew my head gasket that same day and was bummed for the both of us. Fortunately you had seemed to have escaped without much harm, but now it seems there are some lingering issues. Well, not long after I replaced my head gasket I made an attempt to drive up to Seattle from southern California (without much shakedown time). I was trying to push my land rover 200Tdi up over the pass from santa clarita in fourth gear at about 2900 rpm, which I thought was a safe max, considering EGTs were below 1200 f, while oil pressure and engine temps were also good. The engine seized and couldn't be restarted until it cooled for about 10 minutes. When it did start it ran rough, but I was able to drive it off of I5. When I examined the engine, I found that the pcv was now highly pressurized indicating blowby. This is my first suggestion to you is to check for blowby, by removing the oil filler cap or the pcv hose and checking to see if you detect any extra pressure. I hoped that I had blown the head gasket again or maybe the valve lash was off on one of the cylinders. Well, I pulled the head off and found that one of my cylinders was badly scored. What I surmise is that this piston had expanded enough to cause the engine to seize and the cylinder wall to become scored. Why I suspect you might have the same problem is that I have similar symptoms to what you are experiencing (but to a more extreme degree). It is very hard to start it cold and it smokes like crazy, but when it warms after about ten minutes, the smoke is much reduced and the rover becomes driveable -- to the point of almost being normal, but still somewhat smokey. I decided to add Restore Engine Restorer to my oil to see if I could regain some of my lost compression and this is what I found: The engine starts instantly, but runs really rough and smokes heavily for about ten seconds, then moderately rough with moderate smoke for about 30 seconds. Then it suddenly returns to almost normal, with absolutely no smoke, and I can drive it quite normally. I really hope you don't have the same problem as I do since I will need to do e rebuild, but the issues do seem similar. I don't know exactly which modifications you performed to your fuel system. I modified my injector pump a bit. I added some spacers to the governor spring and added a timing-advance spacer. I also optimized lift at TDC. These modifications, I think, allowed me to push the engine beyond the safe limits. My 200Tdi will need new cylinder liners and rings before I can get it back to being a daily driver, but I am happy I can drive it under its own power from time to time, and I wanted to rebuild it anyway (but not just yet!). As others have suggested, compression and leakdown tests will help diagnose your issue.
We had a runaway on a preparer stroke 6.9 ford diesel the first 6.9's had head gasket problems I worked at a ford dealer someone brought a van in with blown motor they had put a Turbo on it and the head gasket blew and it ran away on antifreeze.
Ford was so dedicated to good experience at this point they warranted it.
Love the content bro! as for the TDI, compression test will tell you a lot. if its low on a cylinder or two, pull the oil pan and check the rods, I've heard of TDIs slightly bending a rod or 2 in turn creating a shorter stoke, lower compression, and no combustion... at cold temps you'll have a temporarily dead cylinder till it warms up. I wouldn't start with checking the rods... obviously check your valvetrain first if your comp test comes back low. keep up the good work and good luck with the troubleshooting!
Does sound like a compression type issue. Easiest way to locate the failed cylinder is a laser temp thermometer on start up. Check the cylinders to see which one is the coldest and start diagnosing that cylinder from there. Could be a failed injector over squirting or no enough. But sounds more like a leak from a valve or a injector cup from too much boost. Love your content brother!
I would do a compression test and check my balance rates on the injectors, while I have an oil sample out for analysis as well. My Cummins ran similar to that cold when one of the injectors built up a deposit that prevented it from sealing up, but then it ran fine warm. However an oil analysis discovered fuel dilution in the oil. I was fortunate in I sent my oil sample in early so my fuel dilution didn't get to a dangerous point. After doing an injector set it was back to 100% normal.
I would check the oil pump chain tensioners. It might have gotten starved of oil. Which would give you blow by until it warms up. VW stopped making the tensioners and switched to a gear setup that costs 2500. I had to get my tensioners from London on EBAY. Good luck.
Like almost everyone is saying, compression test. Do one cold, and then after the engine warms up. Direct injection diesel's can be hurt by prolonged or frequent idling as they will not get warm enough to seal the rings properly at idle temperatures.
Glow plug makes sense. But, what about injector nozzle (tip) failure. At cold it could cause ruff idle but at temp doesn't affect overall performance.
Was thinking the same. Tips or cups
I have no idea what is wrong with your engine, but I am glad to see you playing with the TJ again.
It happened to me in my big rig. Cummins engine ran away, wouldn't shut off. Pulled off air intake filter and stuffed my backpack in there. The amount of smoke spewing out of exhaust was amazing. 😂 Was quite a scene in LA Traffic. Everyone thought my rig was on fire.
My alh samurai had what I thought was pedal to ecu issues. Plugged in vcds and it was communicating. Turned out injection pump was on its way out. Verified this on the tdi injection timing graph. It was off the chart.
My 2000 Jetta alh pops and farts when it’s cold too. When it’s warm it runs awesome. It also has a bad maf sensor so I definitely didn’t over rev it. I’ve seen in your newer video on this engine that it’s a bent con rod. I hope that’s not my problem. Anyways I’m new. Love the channel. Subbed!
glow plug would be my first guess, one may not be working properly causing the roughness at ambient temperature and clearing up as the entire engine warms up to operating temp..
My second guess would either be a piston ring or injector because of that sudden boom when you turned the ignition off, all that pressure from wot to engine off had to go somewhere.
Only time I've seen one run away in person was on a 2 stroke Detroit 6-71, normally, in a marine application they have air dampers in the intake that you can close...this one didn't so we threw a trash bag over the filter and it eventually killed it, that thing was screaming at about 4k RPMs
Are you getting a ton of blow by at cold start? I've seen where a cracked piston or cracked compression ring will make it run like that at cold start. I had a cracked piston, engine ran but something wasn't right, it run a little weird at cold start but ran fine-ish once it warmed up. I ran an injector test and it kept saying #4 was almost out of tolerance and after further inspection I just changed the injector, but still ran the same. I later found out that I had a cracked piston. I would definitely do the compression check.
I would definitely start with a compression test just to confirm that your cylinders have good compression low compression will definitely cause a cold starting issue and would also haze like that out of the exhaust on start up until warm
Cold start issue is likely related to valve contact. A few valves are likely bent and they seal up better when the engine is warm. I had a Honda do the same thing. Adjusted the valves and the misfire when cold went away. You should definitely do a compression test, and likely a cylinder leakdown test on any holes with low compression. I have been a diesel mechanic for the past ten years and automotive for seven before that.
Check your turbo first, could be a seal leaking/cracked while cold which closes off when it warms up. Simple first steps.
Leakdown and compression test, along with glow plug circuit
Notice you hit the 200k mark keep it up brother, love the content 👌👍👏
Thank you!
I say doing a leak-down/compression test with the engine cold and again with it hot. Look for a large variance in one of the cylinders when cold since the problem seems to go away once it's warmed up. If you don't fine anything then maybe it could be the injector or a glow plug. I've never worked on a diesel, but if one cylinder isn't way out when cold and assuming all cylinders are within spec when hot, then it must be fuel delivery or possibly a glow plug since it only happens when cold. Not sure if the glow plugs remain on for a while after it starts while the engine is cold, or only when starting. If you have a spare plug and injector, maybe swap them into each cylinder sequentially if the leak-down/compression test looks normal.
^this
Seal in the turbo? Do you have any crankcase ventilation back to the intake, started sucking crankcase oil? But why did it shut off with the key if that was happening.
Mate, I don't care what you do, drive, build or even work on the Landrover you are entertaining. My thoughts on your problem, it's a VW motor ;-)haha but I look forward to the rebuild cheers
Nate. Considered fitting a pop-off valve ? This ensures when the turbo is boosting, it can be manually set at say 19psi, so over-boost is vented to atmosphere ! V.
Nate, many Bosch diesel injection pumps advance fuel timing for cold start. Probably uses intake temp sensor. If anything prevents this slight advance in timing on cold startup. Chug chug smoke. Sometimes thinga are coincidence, I don't think your bad startup is related to your momentary rev. Chase this cold start fuel timing idea down. I had a 6bt act up when a single wire got disconnected on the back of the pump.
I had this happen to my 2002 jetta TDI.. seals in the turbo went out and pumped oil straight into the intake. tach pegged out at 5k, and i tried dumping the clutch in 4th and standing on the brakes. before i got on the brakes it did a nasty burnout, then once on the brakes it slipped past my clutch and threw rod number 3 threw the block and bent the other 3.
Wow man!
Turbo seals are a common cause for sure. I bet that was wild to see in person
@@DirtLifestyle haha im sure it was for everyone else at the intersection. now it has a VNT17 turbo, 1019 injectors, 3 bar map, and a stage 4 malone tune. so in the end, i got a car thats WAYY more fun to drive and still gets 43 mpgs driving it like a race car.
Have seen a heavy duty truck, where the engine twisted the driveshaft 3 times before snapping it, and then threw a rod through the block.
Had this twice with 1980 VW Rabbit 1.6 TD .. once from PCV back feeding oil to the intake when the engine was worn .. rebuilt the engine, but should have replaced the turbo, next time was turbo seal .. Pistons hit the valves at 6000 rpm before I could stall it, it still ran fine with valve inprints in the piston tops .. Sold the Rabbit after the second time, told the new owner to get a new turbo or it would do it again😓
@@Oz4me_craig ooof. I should have seen mine coming. The day it blew up, it bounced limiter at a red light and came down right away. But I drove it again without looking into it. And it ran away. That was also maybe a year into owning it.
if you want to go minimal effort - Try the old seafoam in the crankcase oil trick see if it loosens anything up that's sticking when cold.
Some good comments below ref heater plugs and intake cracks.
I was in a large industrial ammonia leak (refrigeration) and the warehouse guys made the truckers shut off their engines before evacuating. Apparently ammonia in the intake of a diesel can make it run away.
I called it on the throttle pedal issue over on the swapped trucks page. A good guess lol!
does that VW engine have an iac valve on it? i think the "Pop" at the end of the over rev damaged a sensor or something in the idle circuit
Well that was a heck of an intro.
Lol
Finally, I was waiting for this video and now gonna enjoy watching it 😎
Much appreciated 🙏
@@DirtLifestyle now that I watched the video I thought the same might be an injection issues u have maybe one inyector is getting stuck when u start it cold, I'm not a mechanic but those are my thoughts.
Intercooler and hoses was full of oil. Extreme angle of climb sucked oil into intake. Engine ran on. You turned key off and throttle plate closed as it should to avoid run on.
Now you need to check for damage. Do compression test and cyl leak down test.
Im no diesel specialist but Michael Cox from Bronco factory does injector cleaning. Maybe injector clean and a fresh set of glow plugs will make it run better
I'd say start with a compression test, then drill out an old glowplug to make an adapter to do a leakdown test, that would give you some indication of piston or valve damage.
Two ways to stop it;
Like you said, Seal the intake if possible!
OR, for a manual, put it in 5th or 6th and dump the clutch and jack on the brakes!
Did your diesel guy check for a bent push tube ( push rod). usually on larger diesel engines the valve s and rockers will survive some contact with the piston. have seen quite a few bent push tubes. If you have a way to do acylinder leak down test, you can hear if a valve is bent because the air will escape past the bent valve and you should hear it.
They do not have push rods but I've seen this on an old 400 big cam Cummins. Also wore a lobe off
Take a look at your turbo, overboost or turbine wheel over speed can cause some similar issues. Also wouldnt hurt to look at some live data on your injectors to make sure they are OK. Make sure the balance rates are within spec.
In my country i have tons off tdi it 300h to 500+ hp and cold start problems it's almost always hydraulic valve lifter our piston rings, but i think it's the lifters, Ina black makes very good valve lifters
I have no idea about diesel engines, but do need to say something. Of most importance, you sir, have grown, not only in your content, but also your delivery. I know you left your other job to pursue a new path but you, IMHO, have exceeded the limits of YT. Yes, subscribership will continue to increase, but believe you can provide so much more to so many more! Second, did you really threaten that fly?!? 😛 Stay safe out there and First Class Thumbs Up!
I've had a diesel runaway before but it was a mechanical pump we had to choke it out by stopping airflow. I had never heard a diesel backfire before til that clip. Seems like it's possible it slightly damaged a valve/seat. I've had cracked valve seats cause performance issues while cold, then seal up as the engine warms up. BUT I do not claim to be an expert, just my dos centavos.
Love your diy/education content btw. Probably moreso than the wheeling.
I think a head crack between the valves is certainly possible. I've seen this on high mileage TDIs as well
@@DirtLifestyle that's true too. I don't know VW well at all. Well... Looks like you got your work cut out for you. Heh sorry. Look forward to hearing about the official prognosis, etc!
Glad it's still running, but yea I feel like it could be anything you said, without doing at least a compression/ leak down test. Cooked something electrical? Damaged valve? A combo? I don't know much about diesel, but I saw a motorcycle's throttle get stuck open, and the bike wouldn't start or idle, until hot, ever again.
Glad you got it figured it out brother 👍👍
I suspect a bent valve. Try a leak down test on each cylinder with all valves “closed” haha. Struggling to imagine how 4-5k rpm would damage an injector. And the smoke was instantly white at the Moab incident. I think an injector failure would be more gradual than that. Keep us posted! This one’s tough to figure out!
Best way to stop a run away diesel if you cant yank the intake tube off to choke it out. Is to take your fire extinguisher and clog up your air filter to choke out the air flow to kill it. The only worry u have then is cleaning out your airbox and replacing your air filter. That's what we had to do on one of our n14 cummins powered semi trucks.
I'm a big fan of starting with the easy stuff first.
Glow Plug
Injector
Compression
In that order would probably be the easiest to troubleshoot.
If low compression, a borescope may give you some hints.
It does sound like glow plugs
My first thought was glow plugs.
This is why I warned you about the CRD Liberty. Mine ate a cam sensor and after that it was nightmare city… definitely glow plug related, they were infamous for that. They had Bosch glow plugs and controllers, I bet your TDI does too. Electronic crap is the worst, I’d rather have something broken I can see.
From my experience it seems that you have some valves not seating properly possibly bent. Once your engine warms up to running temperature the valves are seating properly. I’ve seen this on 5.9 Cummins some catipillar and 6.2 GM diesels during my military service in which a head rebuild fixed the problem. Check your turbo out also. I’ve also seen worn seals and even cracks that are easily missed during disassembly cause a similar problem from an over boost.
Wish there was an easy way to get a peek at the valves with a bore scope. But without a spark plug hole, pulling the injectors would kill two birds: inspect injectors for damage and bore scope the pistons and valves.
But, if the camera angle is not conducive to see it all you’ll still have to pull intake or exhaust.
Haven’t done a leak down on diesel -only deal with gas. But that normally tells me if it’s intake, exhaust or rings by where the air goes.
That said, bad is bad and doesn’t normally fix itself as the engine warms up. Unless it’s a lifter (gas fueled reference) finally joining the party after pumping up.
And it will get worse if ignored.
What made the pop-off noise and smoke under the engine during the Moab shut down? Was that steam from the overflow or radiator?
Could something (overheat) have damaged the wiring or t-stat so it runs crappy when cold due to not enough fuel?
Glad to see the TJ is back but I think many of us still have questions unrelated to the engine. Still curious on the front axle situation and what happened to the sticky tires though. Since you're one the trend setters for smaller axles and big tires, it seems like a huge shame that you broke two axle shafts, swapped tires, and left us hanging on what's really going on with that.
Probably, it is a series of issues and circumstances rather than a single source fault. Each on their own wouldn't do too much, but under the circumstances at the time, they compounded to cause the runaway. It does certainly sound like there is a throttle issue so that would be one rabbit hole to start chasing down. You had mentioned the condition of your turbo too, and I strongly suspect it is the source of the oil that fed the runaway. Adding in the vehicle dynamics of getting in, and out of that hole would have shifted the fluids considerably, and to enough of a degree that it fed more oil to a hot, revving engine's intake, and it took off on you. Without at least the three factors of turbo, throttle, and vehicle dynamics, I don't think it would ever have come to that point. It's more work, but I think you will find multiple smaller issues, rather than a single "Eureka" source. Looking forward to hearing what you find Nate, good luck!
I have had 22R and 22R-E's that did this. They had very low compression, ran great when warm. You prolly fried some piston rings, or they did not get proper oiling while at the angles in the tub, that would cause the rings to over heat and fry. Do yourself a favor and get a OM617 much easier to work on, and a lot tougher of an engine.
He has a om617 in the blue gladiator but he isnt a fan if i recall.
They are heavy and kinda gutless. Have not seen any of the gladiator episodes. The strength of the OM617 is in the lower end. Stock they are 125hp and 181 ftlbs so weak. Popular to mod in Europe, $2000 dollar swedish fuel system and a bigger turbo solves it. The lower end is rated for 400hp. So stock they are dogs, but modded they can be beastly.
@@iankovac1878 yeah watch the low buck truck series.
The PD engine is in my opinion the best engine VAG have ever produced, ultimately strong and reliable. Looking back at the video of the fault it doesn't look like a 'run on' as you say (it would be reving a lot higher if it was) definitely a throttle pedal issue. I was a VW technician during the run of the 1.9 PD engine and seen a few run aways, after cleaning out the intercooler and pipes, fixing the cause.. usually turbo failure they run mint.
Looking at the exhaust smoke in the video it looks like there is a constant 'puff' of smoke indicating a possible missfire. My first go to would be an injector, unfortunately with the injectors being inside the head it's not so easy to just unplug one and find the culprit. My first way to go would be to use a stethoscope on the side of the head next to each injector, maybe you will hear something that sounds different to the rest?? Other than that it would be cutting the injector electronic feed somewhere in the loom one by one and seeing where the missfire lies...
Good luck dude 😬😬😬
Assuming its a VGT turbo wonder if you hurt it with a ton of compressor surge when going from redline to off..
throttle position sensor maybe it's bad and now it's slightly "pressed" giving to much fuel till its warm? could have carbon build up on valves and they aren't seating right losing compression. till they heat up and get just big enough to seal?
The throttle position sensor is the accelerator pedal with this type of diesel believe it or not lol. And it definitely was a problem but not the current problem. But a theory though
@@DirtLifestyle does it have an actual plug in sensor on the pedal? my 2k tundra lost its sensor and to the floor all I had was 2grand.
I think a compression test would be a good start. Could be any component that swells and seals with heat. If it’s rings, you’ll know with a test. If it’s a turbo, I suppose you could do some sort of vacuum test with soapy wooder on the charge pipes
Cyclinder leak down test..through A glow plug port..might dig any upper end issues
Great information here!! I learned something for sure. Also, I don't think you Milwaukee battery is fully inserted in the charger around 1:40.
Compression/leak-down should narrow it down. I was thinking rings because of autocorrect when heated. I think a cracked skirt would present different. If your friend is a TDI mech then I’m sure he checked the pulse and flow on injectors. It doesn’t sound pressure related either. Good luck. Looking forward to finding out what it is when you find it.
Sounds like wore rings. Low compression till it warms up and takes up the space. Also blue smoke means burning oil so that also leads me to believe wore or or broke ring land. Run a compression leak down test
I am not a diesel specialist, but it seems to me like a valve-related issue, possibly a bent or tulupped valve letting just enough compression by to make a funky cold start till things can warm up and expand to lock in the compression. probably an issue to fix in the long term but at this point drive it till winter. But a cold leak-down test will probably tell you what you need to know.
Side note I work on diesel tractors with a lot of mechanical injection systems and build race cars.
I dont know much about vw how ever I had a similar cold start issue that I ended up rectifying by putting a new glow plug relay in never had the issue again
First thing I would do is a compression test - then hook up the scan tool and see what my injector balance rates look like when it is cold - that will tell you if one cylinder is adding or pulling back fuel. A bad glow plug will throw a fault code on that engine and it should throw a cylinder contribution fault code as well if an injector is not fueling correctly.
Still enjoy your videos we have been away for a while.
I would definitely check compression cold and hot
It sounds like the rings aren't seating cold, and once it get hot it seals up
Dont want to be negative but my guess is a slightly bent rod. Enough to run rough when cold but clears out when hot. Happened to my idi mk2 jetta.
I'm leaning to Valves or Rings.
Most common true run away is from the engine using its own oil as fuel. Usually over the piston rings or from a oil soaked intercooler. For emission reason the will vent the crankcase into the intake often before the intercooler.
I've seen mechanical pumps "run away" as in you can't control them but as long as the internal govoner is operational properly it doesn't cause damage.
Is short if you can turn off a key and the engine stops its not run away. You just can't control the throttle.
I know someone who had a ALH runaway for 20 minutes. He thought it would explode it was revving so high. He added oil and it started back up without any damage. I suspect you have a dirty sensor from running dirty on the overspeed event.
I'm not as familiar with the vw tdi but I do know that some of the latter ones had cam operated injectors that were electrically metered and they could be damaged by an over rev
Love the video! I was wondering what was going on with it. Please please do a 1st gen 4Runner build? 86-89 hopefully 22re ifs for something different then your normal solid axel builds
Make sure your oil level isn't going down. Could be filling the cylinder with oil as it sits and burning it out as it warms up. Someone with a scan tool should be able to shut down each injector one at a time. Maybe if you can do this while it's cold you can find a weak inejector. That or an injector itself could be leaking down and dumping raw fuel as it sits. Not sure if it's the same engine in the forklifts I work on (linde forklifts used to use vw engines) but we've also seen the fuel rail pressure sensor (on the crank side of the rail) cause a leakdown (loss of prime) causing extended starts but not rough running conditions. Also I don't know what temp you're starting it at but glow plugs could also be a slight possibility but you'd probably get a code for that.
I would say you have nicked a valve to piston . While the cam was out did anyone check the installed height of the valves cold ? A slightly bent valve can seal hot better than cold as everything grows hot . The longer you run it the better it will run if that is the case the valve will slowly straiten out until it breaks .
Since we have quite a few of these diesels over here... I guess that you have a faulty injector, glowplugs really don't do much in warmer ambient temperatures and even if it would run just fine but needs a few more seconds cranking. Check compression, faulty injectors often cause temperature problems that can lead to severe damage.
First, I don't know what the problem is. When addressing engine health issues I always first do a leak-down test on each cylinder. This will tell if there is a problem and begin to pinpoint where the problem is. You can detect each one of the following: a leaking head gasket, leaky intake valves, leaky exhaust valves, and leaky rings.
Then inspect the turbo. An oil leak in the turbo is the most common runaway scenario now that most are not mechanically injected. Since you may have solved the runaway problem with the new throttle sender, it may be a long shot though.
Since refurbished TDI injectors are about $300 a set I won't recommend just changing them, but I'd lean toward a weak injector, not functioning well when cold.
Does it usually smoke that bad or was it getting oil into the combustion chamber past the rings at that angle? I'd check compression to make sure you didn't bend a rod from oil getting past the rings. That would cause it to run bad when cold and get better when it warms up.
are injectors for the tdi expensive? might be an easy way to find out by just replacing them, or if you have enough time, send them off to be cleaned and tested.
Its valves my friend. But I wish you luck on figuring out the mystery!!
~local washington jeeper
Have you done all the typical upkeep maintenance on it since? Oil change, fuel filter, injector cleaner/fuel system flush, cleaned intake piping etc? And is the throttle pedal code cleared and staying clear? It definitely seems like there’s a fuel burn issue (something mechanical) but if the electronics aren’t happy, I’d definitely look to remedy that first. I know on the ALH the cold start cycle messes with injection quantity, so that could certainly be part of the issue your seeing with fueling. Looking forward to more content with the TJ and even more so to the eventual resolution here!
How do old diesels turn off regularly?
A shut off solenoid on the Injection pump 👍
Check fuel lines, might be sucking a little air then worms up and expands and seals up.
Perfect timing for lunch 😀
Lol good!
I don't know much on vw diesels but is this one have glow plugs take a ohmmeter a measure the resistance when cold in the plugs and then afterwards when hot and compare the resistance the lower resistance is the cilinder on low compression engine must be running
So engine over speed can damage a number of things. But I’d check the turbo. As a hundred RPM loaded overspeed can be 1000s in shaft speed RPM, if it’s worn the bearing it could be ingesting oil until it warms up.
Hey bro. Injectors are rated for a certain compresión and speed. So they are rated. They may have gotten messed up because of the over speed. No for the pedal issue. It could have been the angle causing a short in the harness making the engine go crazy. You should be able to do an overlay to the ECM just need to know the wires that go to it. I watch you’re videos all the time. Great stuff.