What Happened to the Jeep Comanche?!?
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- เผยแพร่เมื่อ 28 ก.ย. 2024
- Today we’re trying to get the Jeep comanche back on the road again! Something is wrong but we found out after we fixed that, something was worse…
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I could type a whole novel about my experience with the 4.0 running like crap once it warms up but here's a super summarized version. For starters it's an 05 TJ and probably means absolutely nothing to your situation. It started with cam, crank, and 02 sensor codes. After replacing all of that she ran great for about a month but still got some random 02 codes. Then I found something about resetting the computer memory so it can re-learn the new sensors. (Disconnect the positive and touch it to the negative for 30 seconds to discharge the capacitors in the ecm and reconnect, turn ignition to on but not start, headlights on, headlights off, ignotion off) Ran great for a few weeks and then my alternator quit, bought a new one and still no charge. So then I dove into the wiring and found a bunch of ground terminals on the engine that weren't in the best shape and replaced those. Alternator started working and the 02 codes were finally gone but I was back to it going into limp mode after it warmed up but just getting getting crank sensor codes. After nearly setting the jeep on fire to collect the insurance money and countless nights combing through all the "expert opinions" on the forums I kept seeing something about non Mopar sensors being problematic. Luckily I still had my old original sensors and put them back in and reset the computer again without any expectations of it fixing the issue. Well it's been 3 months and she's running perfect for now🤞 Now I just have to tear half the motor apart to replace the rotten freeze plug I've been patching with jb weld to get me through winter. And yes it's an 05 with a rotten freeze plug because I guess jeep saved a ton of money using steel plugs instead of brass🤦♂️🤬
I'm sure my novel won't help you but it might help somebody with way less patience or mechanical aptitude than me to NOT buy an old-ish jeep
I may be wrong but didnt he say it was a renix jeep and wouldnt that mean its a v6?
@@danimal865 No renix is the computer on the older AMC jeeps inlin 6
The problem is that none of the above applies to a Renix Comanche. The Renix ECU doesn't "learn" anything. It's a cold start, every time.
I had a 1998 Jeep yj with 4.0 L six was running much like yours had a warped intake manifold got worse when hot
Machined the head and put new throttle body injector ran like a top after
On the freeze plugs you might find that most often its owners who don't flush out and replace their coolant often enough that have problems with freeze plugs, radiators and heater cores. The anti-corrosion components in coolant do fail over time and the system then needs to be drained, flushed and refilled on a regular schedule before that happens. If you wait until the coolant tests out as bad then damage has most likely already started. I've only had freeze plug issues on used vehicles where the previous owners were lax in flushing the coolant. Same with brake fluid, after two years it has to be replaced to get the best service life from your brakes.
On vehicles I've owned from new that have steel freeze plugs I've gone 20/30 years or longer without an issue just due to following best practice on coolant flushes. Never had a brake line rot out internally or had to replace a wheel cylinder/caliper either due to following a 2 year brake flush schedule. Some will counter that on brakes you only need to flush brake fluid if a test strip inserted in the reservoir shows its bad however that gives you a false sense of security since brake fluid does not recirculate back to the reservoir on most systems so you can end up with pockets of failed acidic brake fluid eating away at various components throughout the system even when a test strip indicates the fluid in the reservoir as good.
Preventative maintenance is much more convenient and cost effective than waiting until something breaks.
On a used vehicle even if the seller "claims" that maintenance is up to date I presume they are mistaken (or worse) and treat it like a vehicle that has not be serviced correctly for a long time. So far judging from what I've found most sellers over the past 50/60 years have been mistaken with a very rare few actually being correct.
On the codes you really need to look past just code reading and start looking at the data logs after putting on your Dick Tracy hat otherwise you end up like Inspector Clouseau bumbling along and accidentally stumbling upon the solution after a prolonged ordeal.
Glad you found the root cause in the bad grounds which is why I tell the kids to check all your grounds first before doing anything else.
Best!
I love Comanches don't give up on this build. By the way Rudicon looked tough as nails today in Matt's video.
Rudy is back! Missed your adventures.
To a mechanic’s ear, it sounds like you possibly have a fuel delivery issue, ie. fuel pump on the fritz or plugged filter. I’d check/clean all your grounds as well. It also sounds like you might have a slight ignition timing issue, but that could stem from low fuel delivery under full throttle. If your exhaust smells excessively rich, it might be a timing issue such as your spark advance not advancing. I’ll be waiting to see what you find. Keep up the good work. Enjoy the content and also really digging the Charger.
Rudy: I don't wanna get it on me!
Also Rudy: I'll taste it!
😂😂😂😂😂😂😂
Well, there is that. And there is, you have this thing on a trailer(donor wagoner)and instead of bringing it to the shop and or in the shop,(so you are close to all your tools) the work is done 50-100 yards away from the shop. And only AFTER trying to carry it that far does he get a wheel barrow. 🤷♂ Planning does not seem to be his strong suit. 🤣 Which is why at the last minute he is trying to fix it for Easter which is when this was published. 🤔 Plan, KISS and the world can be an easy place to live in. 😉
Good thing I didn't step in it...
Rudy - Call the Bleepin jeep buddies and do an episode together to troubleshoot the Comanche problems. They could probably trouble shoot this blindfolded. Hope I'm not giving them too much credit but ''share'' each other as a resource to solve the problem. Love the videos you put out - keep learning as you go - you get better every episode.
Mine was doing the same thing. Fixed it with a 5.3 😂
! You found my '87 Wagoneer! Bought one new in San Diego. Definitely not off-roaded but good for two new kids and groceries in the rain. 195 hp 4.0! Has possibilities....
the early model engines used a soft lobe cam and over time the lobes junk out and do exactly what yours is doing you can replace the cam but i would go v8 or v6 my self
I bought a Comanche when they came out. Specced it to be an economical commute vehicle for the Winter months and nothing else planned for it. Few options, 4x4 but nothing off-road-ee. 4 cyl. with the 5 speed manual. Whoa did I love that vehicle and used the livin' heck outta it. Had more adventures than I ever dreamed of (including a couple of saved-my-ass moments). Owned it for, like, ten years, no major mechanical issues, but rust finally hit, and things like the headliner dropping, just age issues. Then I got t-boned. Sad day.
Regarding the engine running bad, I would check for a drop in fuel pressure while your driving it using a mechanical gauge.
Oh man your bring back my younger days of doing that stuff lol
Thx man👊💯🙌🙏
That’s such a cool truck! I love it! Hope you can figure out the issue! The lift and tires look amazing!
Don’t give up on it! I would love to see more content with the truck!
The two most common problems with the RENIX 4.0L. are CPS and fuel ballast resistor. Known problems with "new" CPS. Only get the NAPA or OEM ones, others have quality issues. Ballast resistor can be bypassed to make it run until you get a new one. Cruiser54 is a great resource for the Comanche. Almost all of the problems(and fixes) in one place. I love mine, and hope to see yours on the trail soon.
When he listed off what all he replaced I immediately thought the same on the CPS. And +1 on Cruiser, dude's a Renix professor.
Same thing here. My 90 XJ ran just like the comanche, replaced the CPS and didn't help. My issues came from the harness. 23 year old Mopar wiring against a hot block does some serious damage. I diag'd the wiring and values were good, until one time they weren't. The engine would heat the wiring and short it out, but intermittently. I suggest pulling the CPS wiring harness all the way back and check it.
👍 I was trying to remember it's correct name that dang ballast resistor if it corroded, cracked or damaged. A replacement one years ago was a PTA to find in early 2000s.
The fuel pump ballast resistor is only there to reduce fuel pump noise...delete the silly thing on any wheeler! X2 on Cruiser54's Mostly Renix info stash, invaluable for any Renix owner.
Did you check the coil? There was a recall on them in the early 90's. Had 2 go bad on me with 2 different symptoms. One, intermittent miss under a load causing reduced power and the other engine would only run at idle.
Some possible sources are intake manifold gasket, EGR valve, water in the gas tank - especially if it runs ok cold but gets bad when warm.
I had a 96 yj doing the same thing before turned out the injector harness was bad got some new pigtails and solved the problem good luck!
ok so heres my take on your Waggy, just like my 1987 2 dr XJ, its a holy grail wagoneer, its the last year of AMC, and the first year of the 4.0 in the XJs. now, if youre really lucky it will have the factory towing package with the rear Dana44 and limited slip diff like my XJ, which was only available 87-90 in XJs, its much more common in MJ Comanches. your Boston is awesome he should be in every video👍👍
Got me an 88 2dr just swapped from closed to open cooling system this weekend and upgraded the trac bar and mount. Got a small coolant leak from the waterpump inlet tube, should have used pipe sealer rather than Teflon tape😑
At the beginning you got in the Comanche and ran it through the gears. When you put it in park, I could hear the parking pawl clicking clicking across the spinning gears of a working transmission. At least the transfer case was an easy fix. Good luck with the engine issues.
Hopefully it is as simple as a plugged fuel filter or pickup screen in the tank
Seems to be a fuel related issue to me. Could be wrong but a good place to start anyway.
MAF, controls fuel ramping.
Idle issues are from probe temp vs resistance. Replace.
Great video guys....excellent content.....fixing and repairs....thanks for sharing this with us
My daughter’s 90 fj was doing similar. She had a vacuum leak on the little hose that goes from the throttle body to the aic. The fitting was broken.
We also did cap, rotor, plugs but the vacuum leak was the culprit on herds
I was driving through Moab, just past Rory’s shop, and saw you coming off a side street. Had I known at the time that I wouldn’t make Houston by 3p Friday I’d have stopped to say “Hi”.
I do like your content; waiting for more C-10 action with Kaulin.
My first vehicle I bought after graduation was a 1984 wagoner limited select-trac,
Put a 4" rancho lift and wheeled it.
Nice way to grow up.
I think it's the blinker fluid sensor, if it shorts out it'll start running like a blinker, off and on, off and on.
Have a hippidy hoppidy holiday 😊
Blinker fluid is only on the early Dodge Vipers. True fact, you can see the fluid level in a little tube in the headlights. th-cam.com/video/LXe4LRuc1f0/w-d-xo.html
I had a 95 ZJ with the 4.0 It did the exact same thing your MJ is doing. It ran fine at cold temp until warm. I replaced the o2 sensor. Has been fine ever since.
FWIW: My 94 XJ had similar issues as your Comanche. Turned out to be the Cat Converter was pretty plugged / clogged up. Replaced it, and then it ran fine.
Distributor or the breaker plate under the cap.
I had an 87 with a similar running issue. The mounting tab on the distributor housing broke and allowed the distributor to slide out and twist under load. It would run at idle and wot but got progressively worse and finally wouldn’t run at wot. New distributor and a spacer so that the mounting tab tightened flush was the answer for mine.
2 thoughts, vacuum leak or half blocked fuel filter. For vac leak test, get the motor running rough, then spray tiny bursts of butane close in around the induction system. If the engine note smooths, shes sucking in butane at that spot instead of air. Long bbq lighters with the flint disabled should be quite accurate and reach difficult places. Face shield on, extinguisher beside you and definitely outdoors with pauses to let unburnt butane disapate. But ive never had an issue doing it with due care - and am safely in New Zealand!
I have worked on a few Comanches with that problem found it to be the exhaust system not enough compression for the motor or not enough getting out good luck
Could it be as simple as a gunked up fuel filter? I know almost nothing about mechanic work, but it reminds me of an old work truck I once had to drive around. Good luck sir and happy Easter to you and yours.
It was a great idea to leave the drip pan sitting directly under the transfer case to soften the blow as it fell free. I wonder if the mystery fluid makes good rust inhibitor? That part of the video made a real SPLASH.
Rudy it seems like a fuel pick up issue because it doesn't seem to get enough fuel when you push on the throttle. Something seems to be restricting fuel. I know you will get it figured out. I hope you guys have a good time at Easter Jeep.
Are you going to be building a rock crawler for Janelle? In my opinion she definitely needs one because I know she will be great at it
I had that once, it ended up being the fuel pump on mine, good luck.
Nice to see you fixing the car then! Sad that is was not running good!
Rudy, I know very little about cars, but I have encountered a situation where a clogged exhaust caused similar things. The one I seen had a Muddobbers nest in it. Just a possible issue. You’ll figure it out 👍👍
Good idea but our ears tell us different though.
This one time at band camp, I probed the injector connections, wallowing them out while checking for impulse. Making it run sporadic, and I beat my head against the wall in frastration. Finally, an old high buddy started wiggling wires and caught the problem. 😁
My grandpa had one of these until he couldn’t drive anymore. I’d love to have one some day. Cool little truck
Fuel pump, perhaps? Funny coincidence...I discovered my T-case was bad on my Comanche on a family camping trip! haha. took it to the dunes, went to go out on the sand, and had a horrible banging noise. thought it was the front end gears- but nope....transfer case chain was so slacked it was skipping teeth. Still need to fix it. We should have put together a Comanche trail ride at EJS next year. I'll get my mine done by then!
That was sooo funny watching you trying to carry the Transfer case.
Rudy tastes unknown liquid. Starts whole new pandemic. 😂
Andromeda Fluid. 😶🌫️
😂
Following the lead of the Car Wizard, taste to determine the fluid
This past summer, my Odyssey quit moving, just made a weird noise. We were on vacation, 800 miles from home. Honda diagnosed it as a bad tranny, and replaced it under extended warranty. We picked it back up, drove the 800 mile trip home, and the next day, it was doing the same thing. Took it to my selling dealer, and he diagnosed it as a bad right front axle. Ironically, that was my first diagnosis, but the first dealer told me I was wrong. Turns out, that model had four different right front axles, and the independent who installed it, put in the wrong one.
It could be a bunch of things that make it run rough like that. I've had a clogged up catalytic converter cause problems like that. It idols fine, but when you try to increase the air flow (especially after it has warmed up) it just chokes up the engine and runs crappy. It's pretty easy to just open up the exhaust somewhere upstream of the catalytic converter and see if that makes a difference. Good luck finding the problem.
Have you checked for Fuel being too hot at the injectors. 4.0 had a heat issue, and a heat shield and injector wrap help wonders.
Check the distributor
In those years I'm pretty sure it's a renix generation the distributor not only does timing but it messes with the fuel as well. I had the same problem in my 90 cherokee and my buddies 89 cherokee.
Great to seeing you are back! What about the C 10?
Cool truck, maybe fuel supply issues since that wasn't mentioned as attended to. Good luck!
The only things you didn't check was the pick up in the dizzy and the oxygen sensors, I have had those go bad in the past causing similar issues
I had one. The sock filter on the end of the fuel pump disintegrated and plugged up the pump. Shit would run fine sometimes, sometimes it’d run like yours. It would still build good fuel pressure. But the flow wasn’t there. Might be worth checking out.
I'd be looking at the spark side coil distributor leads, coils do brake down when they get hot and under load but will run fine at idle
Had S10 chev pickup do same thing acted like a fuel problem, was a bad coil going out
Yes me too. Got close to 1000000 miles total pass 3 trucks. Every time its been ignition modular
Fuel pump (check pressure at Shrader valve on fuel rail), vacuum leak. Also, I’ve had bad (new) crank position sensors. I know they’re pain to replace but I would try installing a known good one. I also recommend OE or OEM for that particular sensor.
1. Distributor/coil/ground
2. jumped time a tooth
3. Wiring woes
I've just chased that gremlin on one of my G20 TBI Chevy's
Ya might wanna check your gas cap. Mine did the same thing and I swapped the gas cap. Problem solved. That model had the remix ecm in it
Mopar upgraded them. All these vehicles have electrical Grimlins Dandahermit
Sounds very much like fuel delivery issues caused by any number of problems. Dodgy wiring getting hot? Fuel line getting hot? Vacuum in fuel tank? Mobile gunk in fuel line/filter? Had last problem with a ride-on mower with very similar symptoms. Or other more esoteric problems many have suggested here. Make a temp fuel delivery to bypass the existing fuel system and see if that rules out fuel line/filter/tank/pump problems. Check if problem occurs straight away after hot restart or fixed straight away after hot restart - that'll begin to help diagnose or narrow it down. Good luck guys.
Rudy...in the Waggoner check the radiator to see if the coolant has transmission fluid mixed with it...if so the transmission cooler has a leak inside the radiator
Hey!
I did a 2.5 to 4.0 engine swap (tho it was a HO 4.0) and I had similar issues with the o2 sensor. (There were chewed up wires and a bad sensor too)
I wish luck finding it out from Hungary✌🏼
Rudy you are the man , I'd love to see you build something to complete with the morrvair !!!
Good work grate to see the truck on the road
Mine was doing the same thing. I had used Amazon crank position sensor, O’Reilly‘s crank position sensor and auto zone crank position sensor. All of them were garbage and did the same thing. There were no Mopar crank position sensors to be found anywhere so I got one from NAPA and like magic. It all started working again. I later found a Mopar sensor from Puerto Rico and ordered it just to have it in case I could never find one again. I checked the resistance on all the different sensors and there was a wide range on all of them but the least resistance I found was the Eclin brand from NAPA was almost identical to the brand new Mopar sensor, just because the sensor is new does not mean it’s any good. Stick with OEM if at all possible.
Those had a ballast resistor for the fuel pump. I had that issue on my 88 jeep cherokee. It was the resistor on the driver's fender
Sorry for my bad technical English in advance. I had a similar behaving car a few years ago. It was the ABS sensor in the rear axel (I'm not sure if your Comanche has got ABS) which was coroded and sent false signals to the main computer.... Took us quite some time and tries to find but after changing it the car was driving fine (normal throttle response) and is still today. All the best from Germany, Maximilian.
My CJ7 was doing something similar and after replacing most of the parts you mentioned, I finally replaced the Ignition control module and like magic the problem was solved. Just a thought..
My old comanche did the same thing. I put on one of Holley's computers, throttlebody, & a few other parts along with getting rid of the in tank pump. Problem solved.
Enjoying the Comanche build. Can’t wait for tons and 40’s!!!
Just an idea but check harness plugs and see if they have wiggle room. Chased an issue with my 4.0 GC forever. Was the harness plug on the coil intermittently wiggling loose
3 things I can think of being the problem, fuel pump going out, gunk in fuel tank/ filter, then the ceramic resister if it's cracked or damaged, corroded wires that can do that. The first two have been mentioned by others. I got my 90 XJ back from shoddy work done and had that part I commented on busted. I had some issues like it's showing. I'm coming up blank on the correct name for it right now. Now on a good note, the block in that time frame Comanche is possible the diamond in the rough, extra heavy casting block. Great opportunity for building a stroker (4.5- 4.7) motor, then drop 91/92 heads, etc, on. I got one in a 86 Comanche I got for a project in 99-00.
Had a similar prob with my 4.0 check compression before and after it heats up, mine was running 50 ish psi cold and dropped under 20 hot it was a cracked block…… I hope urs is a more simple prob! Good Luck
Good job on your channel Rudy. Met Matt, Jaymie, and Lizzy at the car show. Jaymie and Lizzy were quite nice……
Timing chain, cam position sensor. And there is a small Allen or torx screw on the renix throttle body to set idle A/F ratio. Ask me how I know😂
“I like it and it doesn’t deserve to sit”. That’s how I feel about everything have. People always ask why I have so many vehicles and this is my answer
I say fuel delivery and/or timing. Good luck. I love the Comanche, don't give up on it.
Check the bulk head connector on the fire wall for he ecm harness there bad about pins coming loose and corrosion on the renix jeeps
Thanks for sharing 👍😀
The great thing with those 4.0s ... they are super simple to repair
use the KISS method & dont assume its something expensive thats broken
Make sure the valves are lifting rite, iv had a rounded cam lobe in a sb Chevy 350 that would backfire from the intake
As other comments definitely look into fuel delivery. I would suspect weak pump/clogged filter. Especially hearing how long it takes cranking before firing up. Then once fired up still stutters a bit. The bogging out at fuel throttle is more than likely getting all the air and not enough fuel mixture
Comanche club is the place to go, post a thread about how yours is running and they will have your problem
Also go to cruiser 54’s renix tips
An awesome ride; thanks for the updates!
Rudy,
I have a 1989 xj that was acting the same way. I changed everything you changed. I took the computer out of my 1990 xj and it fixed the issue.
Renix Jeeps rock , it's your fuel delivery somewhere in the system .. easy fix !
Renix stinks. Two issues I’ve had with 4.0’s: there’s a known issue with the middle injectors getting too hot from the exhaust manifold. Some kitchen foil folded into a heat shield helps.
The other thing was the 2” rubber fuel line from the pump to the hardline on the pump assembly in the tank: I had one where it was just regular fuel hose and it couldn’t hold pressure under acceleration, but would start and idle just fine. A chunk of submersible fuel line and new clamps and I replaced a very old pump sock pre-filter. They usually don’t come with a new pump so they don’t get changed.
sounds like you've checked most of the ignition side of things, and doesn't sound rough, so I'd check fuel pressure at the rail if possible, if it builds fine on "prime", then test while running, like these other fella's have said u may have a fuel restriction at the filter/ pump/sock
but if its not a weak spark, its def fuel... assuming your throttle position sensor is sending the right signals (sounded like u checked all the sensors)
If its a renix comanche ground the bracket that holds the relays next to the hv coil on the passenger side under the hood behind the battery it is secured to the sheetmetal with aluminum rivets, drill them out with 5/16 self tapping sheetmetal screws to ground the bracket , hope this helps, the aluminum rivets are poor ground paths for sheetmetal which causes a random ground for any electrical part that uses that bracket as a ground reference
Many renix under my belt. Always expect the unexpected. I chased a very similar issue that turned out to be the coil. Also my current 88 had a upstream 02 go bad that caused some wacky symptoms somewhat similar. At the end of the day, 98 swap it and be done, ob2 is great lol. Super easy to full swap.
Have you checked the distributor bushing for play? If a later engine, it will have a sensor in place of the distributor; looks like a miniature distributor.
If you already know then nevermind. When you change any sensor that’s located on the intake, specifically the throttle body position sensor, you have to ground your PCM to clear the charge in the capacitors. This allows your PCM to relearn the new sensor. Pretty simple to do actually.
1. Disconnect the battery by removing the positive battery cable.
2. Ground the positive cable to the negative cable for 30 seconds to erase the electric charge in the capacitors.
3. Reconnect the positive cable to the battery.
4. Turn the key to on but do not start.
5. Turn the headlights on.
6. Turn the headlights off.
7. Turn the key off.
Thanks for sharing.
Was pretty sure it wasn't the transmission when he put it in park during the first startup. That parking sprag ratcheting like crazy suggested that the transmission was in gear and rotating, there was just something keeping that rotation from making it to the driveshafts.
Also, look for a vacuum leak on something that is thermostatically controlled - i.e. when the coolant warms to a specific temperature, a thermostatic valve opens and creates a huge vacuum leak.
Quality breakage, kid! Excellent 👍
Check the " No Knock Sensor " .
Co2 sensor up line but possibly the down line also. My 99 TJ was acting the same way and that was my fix for it. Best of luck Rudy 👍
Check your distributor down in the block. Make sure it's tight & not broke, & check plugs & wires . All else fails, timing chain to see if it jumped??? God Bless & PEACE OUT Bro !!!
Back pressure from a clogged muffler, catalytic convertor or crushed exhaust. You did make the comment it sounds like a tractor, so maybe your exhaust header is leaking and if plugged, maybe making it sound like a tractor with the back pressure? Should be able to compare exhaust pressure with an XJ. There is actually a pressure gauge that screws into the O2 sensor port to measure pressure. My old man went through this scenario with his Caprice. Also make sure that rubber elbow under the MAP sensor is a tight fit, not cracked and not leaking vacuum. As I recall, there is a small needle valve at the base of the throttle body that can be removed and cleaned. Just make sure you count the number of turns if you remove. I believe there is a cap that needs to be removed. It's been a while since I've worked on these 4.0 engines, so it may not be applicable to your situation.
Hey look, a gas can in the back! Rudy learning from his dad!
Have you checked the firing order to make sure it's not off by 1 or 2 cylinders. Also like someone said check the cat to see if it's plugged up because that can cause lack of power too.
That wagoneer limited is dope!
Not sure if this is your issue but sounds like an O2 sensor issue. My 99 TJ 4.0 had a o2 sensor go bad and at certain speeds it would pop and backfire and I would feel it under my feet. Replaced the o2 sensor and my issue was fixed. This was 10 or so years ago. And it still runs good today.
I put 5.0 fuel injectors in my 1988 Renix and has plenty of power, with no hesitation... but I would definitely check your fuel system. ( filters, injectors, etc. ) might also have a vacuum leak somewhere.
I had a 4.0 do that to me as well, it was a bad head gasket. There are a few test to run to rule that in or out, but sometimes we always assume all problems are electronic and forget to cover the basics.
A lot of times when things cool down or the tension comes off parts is when they break or quit working, I had a Toyota running completely fine parked , came out 20 minutes later in the head gasket was blown .