Or rather a cheaper tool. In other words a cheap OBD2-Bluetooth thingie (ELM327 clone which more or less everyone is), and the free version of the Torque app on any Android device. With that it's easy to have graphs for all relevant sensor values and desired values, and have a look at this while driving, and see what happens when the car gets upset. Haven't seen the video where this was actually yet, but in general I would say that any turbo car might end up in limp mode if air flows the wrong way or in the wrong quantities. In particular the switch over from the intake having vacuum to being pressurized is the hardest part for the computer to handle, and it has to make assumption that things work correctly. If there is some air/vacuum leak the result will be that the O2 sensor (before the catalytic converter) will tell the computer that the air/fuel ratio is off, and the computer will realize that it can't keep the air/fuel ratio correct and thus it disables the turbo until you turn the ignition off and on again. This usually happens within a specific RPM range. Fun fact: at least on some cars you can turn off and on the ignition while in gear. Just let off the throttle before doing that and you won't feel any jerkiness when the engine restarts. Saves a bit of wear on the starter and whatnot.
Hi Ian. I'd have a look at the wastegate actuator. However, if the battery has been flat for a while, get it cleared by someone further up the food chain! Good luck
We had one of these in Canada. On purchasing it had no boost, which was a leaking induction pipe after the turbo. Then a few years later we had an intermittent no boost issue. This turned out to be an EGR valve sticking. Removing it and tapping it fixed it for awhile, but eventually we replaced the valve.
The symptom you described with the ABS light coming on, then a reduction in power, is suspiciously similar to a problem I've just has with my Volvo XC60, which turned out to be a faulty ABS sensor on one of the rear wheels. The sensor was telling the ABS/ESC software that a wheel was spinning when it wasn't and therefore that power should be cut to the rear axle. However, in the Volvo's case it was 'smart' enough to realise it was a fault and would disable the entire ABS/ESC system and allow you to drive the car normally, albeit with an instrument display lit up like a Christmas tree!
Looks like it's over-boosting and then going into protected mode. You're not in the lower gears long enough for the pressure to build up, so I think that's why you're seeing it in 3rd gear. You could try easing through the gears to 4th and then flooring it, confirm that it's boost related and not any other sensor related madness, like wheel speed mismatch etc. Does it have a wastegate, and can you actuate it - by hand, spanner or vacuum pump? If it can't bleed excess boost then it will have a wee fit and not want to play any more. Good Luck Ian, you will sort it.
I had the same issue and it turned out to be the cycle valve/ turbo pressure relief valve. Apparently they are also available on VW and BMW and are cheaper and easier to source. More info on Evilution.
The diagnostic software these need is Mercedes STAR. I know S2Smarts in Leighton Buzzard has it but don't know if there's a place closer to Wales. I know from bitter experience not to let these get within 50 miles of a Mercedes main dealer, the one near me resented the fact they had to touch Smarts and resented even more when my Smart Roadster was getting more attention from their customers than anything on their showroom floor. btw Rob at S2smarts is a top bloke and a real enthusiast, I don't know if he still has it but he used to have one where he'd thrown a subaru turbo and a whole bunch of other subaru parts at it to make 150hp.
Is that the system with a massive control unit? With all the cables it needs a rucksack to cart about? I bought mine to fix a 1997 mercedes 200 as to get that out of limp mode you can only use the diagnostics unit, and it was very user unfriendly but got the job done.
The current star isn't too bad for cabling, it has been known to work wirelessly if you aks it nicely, offer it sweeties and the planets align (use it to do software updates wirelessly at your peril though...).
Loss of boost will most likely be the waste-gate valve (on the turbo). Is there a vacuum pipe to it? Does it leak? Does the diaphragm it actuates leak? Is it electrically controlled? Other than that, the valve itself might be seating too loosely for one reason or another. Perhaps the linkage is past its best? Or the return spring within is weak?
Be useful to get the codes or see live running data on boost pressures, however, my money is on an overboost which is happening when you floor it, leading to limp. In this case, likely worth checking the wastewater actuator and associated plumbing, as well as your boost pressure sensor.
At the end of this video I was reminded how my poor 1971 Peugeot 304 Coupé ended: as a card box storage in a dirty shed... Good luck with the Smart!!! See you soon --- Martin
I've probably made this comment about five times since you bought the Smart to no avail, but it's almost certainly boost control. The plumbing to the wastegate actuator is complex with five hoses and the boost control solenoid (aka cycle valve) is prone to sticking. Check the plumbing on the Evilution site. The cycle valve is mounted on the steel bracket that supports the turbo air inlet pipe (aka TIK pipe). Another, more remote, possibility is someone has tightened up the adjustable wastegate linkage too much so the actuator doesn't have enough travel left to open the wastegate fully. It's also possible, though unusual, for the actuator itself to fail. The crankcase vent valve failing open doesn't cause enough boost loss to be noticeable and I've never seen the ECU going into limp mode from this, though it certainly can cause oil leaks.
Eurn doesn't listen to advise if he can make another monetized video, interestingly he is still spamming his videos on autoshite without contributing to forum fees but those lentils dont pay for themselves, why not tell your story on modgate on the dark wob?
I know the feeling Ian with older car 'foibles' that it quite often becomes a process of elimination by replacing bits and bobs so if anything they can narrow that root cause of the problem without a sky high bill for a 'specialist' to diagnose who after all might not be able to fix an issue. A small leak in a hose can throw a more modern (circa 2000) engine easily so I agree with the approach you are taking. With so many breather pipes and valves everywhere it's a pain, more so where access is very restricted. Many thanks for sharing. Hopefully other Smart owners can help out as you mention.
Id be checking the actuator on the waste gate is working and not seized. As for the traction light, they have a yaw sensor on them over exuberant driving pops the traction light on (I believe to aid stability) . An old trick was to turn the thing 90 degrees to "turn it off"...
My 2005 Astra Diesel did exactly the same thing, and despite multiple garage visits, never able to get to the bottom of it. Ultimately was consigned to being a parts car
When my 451 was messing around and doing all kinds of weird behaviour after a major service, it turned out to be a piece of rust on one of the Abs sensors. All was fine after that was cleared. Dry joints in the computer box also cause problems. There's a video somewhere on TH-cam the explains that better, though for 451 so not sure if the 450 has similar problems.
I had a similar issue with my 2009 Mercedes C200 where my traction control light came on and I lost power if I went above a certian speed. If I turned off the engine and restart it the problem would be gone until I get up to that same certain speed. It was a split intercooler hose. A brand new genuine Mercedes part from a local dealer cost me just over £60 and it fixed my problem. If you have a split intercooler hose there will be oil where it has leaked out as intercoolers will have some oil inside them.
Had a similar issue with my first E320. People online said to change the turbo actuator which I did multiple times and it didn’t fix it. I took to a garage with STAR and they couldn’t fix it. Drove it like it was in the end. Turning it off and on again always cleared the fault temporarily.
My mate had one and the inability to do the most simplest things like change the spark plugs was so bloody awkard we became adept and removing the engine reasonably quickly - we even considered trying to make it 'quick release' we were doing it so often. The trouble is they are such great cars when ok you push yourselves into it sometimes almost too far, and that's why they are a no from me too
@@PaulabJohnson nothing at all to do with the age, I think they are superb little cars - it's just that they did not think at all about making simple maintenance easy. Shouldn't have to take the engine out to change a spark plug.,
@@ChishanFipz I don't disagree. Unfortunately it's a trade off when fitting a small turbo charged engine into a compact city car - space will always be at a premium. The trick with these cars is to use a specialist who only works on Smart cars as they are so idiosyncratic - it's not really the type of car you want to be working on at home. Saying that, there are plenty of 'normal' sized modern cars where even simple tasks require significant engine disassembly = unfortunately the days of stripping down the engine of your cortina on the drive (like my dad did) are long gone. Cars are increasingly seen as just another white good nowadays.
Might be worth a quick visual inspection of the abs rings on the driveshafts. They tend to rust and the teeth breakdown, which confuses the ABS. This usually results in an ABS/Traction control warning. In the early stages, it seems to only kick in when you boot the throttle. I had this issue on my roadster, although it didn't cause the car to fall into limp mode. Even if this is not the cause of your problem, it's still worth checking as they will eventually need replacement.....
Its either an under boost or an over boost. But it seems more like an over boost. Not too sure on Smart car's but I when the VW Audi goes into limp mode it disables the traction control therefore the light comes on. I would guess it points to boost control valve or the turbo actuator something along those lines. Good luck 👍
Exceeding the max boost (18 psi?) would trigger the limp mode on my 450 cdi. Another possible cause is a cracked reluctor ring which throws off the wheel speed sensor that indicates one wheel is turning much faster than the other. Also had limp mode caused by a bad connection on the egr. I got a troble code indicating an egr issue, but seeing as I had blocked off the egr I knew it had to be the sensor connector and not a plugged up egr.
Hi Ian. From memory you can turn the traction control off on these. I believe it is one of combination things you have to press buttons and switch things! I remember switching it off to get up a fairly steep road in the snow one year. BTW they are great in the snow as they are so light. All the best.
You'd have thought a code reader would help but I know from experience that they're not all created equal - what BMW DIS and INPA find over some third party readers is quite surprising. When I saw you struggling to latch the hood on the Smart it reminded me that I need to adjust the bonnet catch on the Yaris - yes, it lives again! New radiator, new maniverter and it runs great. No pong of exhaust fumes any more. How the garage got those rusted manifold bolts out I'll never know.
I also have the traction/abs light come on (well flash actually) every now and again, but in my insurance it doesn't affect power or boost. Not sure this helps at all but all the same..
The ESP (traction control) light flashes at the drop of a hat on the 2 Smarts we've had. It doesn't seem to affect anything. In fact, sometimes, the traction control sometimes activates on tight roundabouts, but not always, despite the light flashing.
Have a look at the sensors, plug it in to a diagnostic machine. We had issues with our 450 smart dealership charged us a fortune for a new crank sensor
Possibly a sticking waste gate actuator? Not sure of the set up on a Smart but would be interesting to know as I'm looking to get one myself for commuting
As my earlier comment you can buy the replacement rings for driveshaft loosen off the centre nut and shocker the side it's cracked you can see the crack in the ring that needs replacing once you've loosened everything off on that side put a long bar the longer the better into the end of the axle and pull you can wangle the driveshaft end out removed the old ring clean off all the rust where it goes back on cos that what cracked the ring in the first place tap the new ring back on in original place and rebuild
You really need to see live data but I’ve no idea what kind of diagnostic gear would give you that. It has to be electronic / electrical as opposed to something physical because it looks like when it’s right, it works really well. If I had to guess I’d say boost control solenoid / circuit? It may be over boosting and shutting itself down to protect itself but the traction control light is a mystery!
An engine management fault will often bring up a traction control light too. This is because the engine management system is interlinked with the traction control system. When the traction control kicks in, it can reduce engine power, as well as braking individual wheels. One fault in a modern car will often light up the dash like a Christmas tree. Especially in Peugeots.
The HubSmart is actually a work of genius, as it is very roomy (for two), well-built, practical and economical. The ultra-safe and solid Tridion body shell does not seem to have any of the rust issues that affected many Daimler Chrysler bodies of the day. However, the (Soft-tip?) gearbox spoils things. We once hired a purple/silver one in Lanzagrotty over 20 years ago now. I remember this car tended to dive between shifts, and losing almost all momentum going up hills because it took the Smart Car too long to find the gear it was supposed to be in.
Limp mode followed by key-off then key on makes me think that it's a parameter out of range leading to ECU invocation of limp mode. A bit like worn injector issues on Renault DCi's for example.
I had a similar issue on a discover 300tdi and fly by wire throttle. The turbo waste gate had seized and at 3000rpm the car lost loads of power, no light or limp mode because it was 1997 car. I suggest you use an OBD on live data to see turbo boost or manifold pressure, ODB doctor on your phone with a suitable Bluetooth ELM327 worked fine for me, and watch the boost as you accelerate, I think you can record too. I am sure the interweb will tell you what max pressure should be. What I did to cure mine (it worked and I sold the car 5 years later still working perfectly) was; Spray the wastegate pivot (where it goes through the cast iron shell of the turbo) with penetrating oil and leave it over night. Then I exercised it, I used an adjustable spanner (difficulty to get at on the Disco as the alternator is very close, so battery disconnected). Obviously the oil goes as soon as the turbo gets hot, but for the first day it was fine. The I exercised it (using some oil for the first few time) every day for a week before I used the car, then I dropped down to once a week. It never stuck again, I actually made up a bar with a slot in the end so I could poke it through the turbo and the slot went over the wastegate actuator rod (just behind the adjuster nut) and I would move it a few time before I drove the car (only needed it once a day). You may also find that the ABS light flashing is a warning for something nothing to do with the brakes, I suppose they use it so you take the car to a garage to get it checked. When the boost control actuator stuck on my Golf GTTDI the turbo melted in less than a 100 yards, so what your experiencing can been seen as a good thing.
Seems reluctant to turn over of half a second as is the battery is low, but they bursts into life no problem.Seemed to do it even from warm during your drive!
A neighbour's Audi TT had a PCV valve fail open. With a turbocharged engine this had the expected result and oil was forced out of every seal and some other places. They finally realised something was wrong when it started misfiring after idling when hot due oil getting into one cylinder and fouling the plug, but by then the engine was an oily mess. They dealt with it by selling it.
The timing sounds like it's late when you start it. It sounds like the knock sensor first cut timing, then boost at X bar of pressure, and it isn't putting timing back in when it's supposed to. Cutting off the ignition resets it, so it's most likely a weak sensor (or more than one) instead of a bad vacuum line.
10:17 ominous words, just casually thrown in, Ian? I see another well-deserved move/retirement coming on for one fleet member, and increased peace of mind for yourself ... unless you're already thinking of something else on 4 wheels ...
Maybe off course here, the SAM unit under the dash have probs with dry solder joints that causes many strange faults, they're affected by water damage too, the windscreen seals are not the best especially if you reside in a wet climate, does it rain in Wales?
I'd try and get the battery to its full running voltage. That can skew lots of readings and generate weird faults. If it isn't the plumbing/wastegate, then it may be that the turbo deactivation is part of the Limited Operation Strategy. It detects an engine problem and so does whatever it can to minimise the risk.
Maybe check the ECU connectors and while doing that, give them a good spray with contact cleaner. My Citroën C2 did the weirdest things that literally no-one could explain at one point. We had the car at independent mechanics, Citroën specialists, even the agents did not have answers for me. After some inspection of my own, it turned out to be corroded pins on the ECU connectors that were related to the central locking, immobilizer, and fuel pump. Those pins are incredibly thin so the slightest bit of corrosion causes them to send strange messages... My dad and I ended up having to solder the wires directly to the circuit board instead of using the pins of the connector again because the 3 pins in question were completely corroded. This fixed all of the weird problems we had. Maybe it helps in your case as well...
What a car, should get Pete Coupland over for a look, definitely the type of car that needs a decent scanner to find the faults. Also looks a little low on the front 😪
Hi Ian, Don't know if this is any help. I have maintained my wifes 451 cabrio for the last 14 years myself. I know the later ones have a Mitsubishi engine, but notice some similarities. Your car is in urgent need of a service and I would find out if there is indeed excess crankcase pressure. If you work through the pipework on the whole breather circuit including the intercooler, I suspect you will find a valve or similar blocked with oil residue (mayonaise),or yet another pipe split. Sometimes if you cannot clear a code or get the triangle of doom, disconnecting and reconnecting the battery after a few minutes, sometimes resets the whole thing. The dealers charge a fortune for a code read and suspect you will struggle to find a Benz dealer that will work on it. If yours does not have a sump plug, I would suggest removing the sump and cleaning it as well as the oil strainer as part of a service. 451's recommend Mobil 1 which I consider a waste of money. I change my wifes Smart oil yearly and change the air filter as it lives in a very hot and dusty world. Decent oil is worthwhile such as MB 229.52 which if bought from the internet can be under £60 for 10 lts. I use this in my Dacia Sandero diesel as well and its excellent and produces very little mayonaisse which can be a problem if the car has been used for short journeys creating condensation which does not burn off. You also have twin spark plugs on the earlier smarts as well. Hope this helps. I would like an earlier Smart car myself.
The turbo hasn't got electronic actuators on it. If it doesn't it might mean a new turbo. Had to have my turbo replaced on my car recently for that reason.
One thing to do is to drive it with a light foot, don't go far into the boost, if at all. Can you drive this car on just the edge of the boost and see if it also throws a fault? You like to drive this car rather spiritedly, and I'm wondering if it's a matter of just kerbing your enthusiast side long enough to actually find out if the turbo is the sole reason it's going into limp mode. I really hate limp mode; our Turbobrick had a transmission shifter position sensor that needed cleaning that was repeatedly shifting the car into second and limp mode.
I'm quite fondling the idea of having one of these cabrios just to use in the city and have a breeze when the heat goes under 30 degrees (hot country here 😂), don't like the way they drive, but love the way they just are... they are still some of a premium here in brazil.. so not so very cheap to just go and get one, but at least the majority is low mileage and well maintained.
Here's my guess. ABS/speed sensors getting confused so going into limp mode. Might not show up as an engine code, as not strictly an engine issue. Fingers crossed you fix 'er.
Smart cars of this vintage have a habit of wearing through the intercooler, the frame that the intercooler is fixed in wears away the plastic. This causes the of air pressure that the Turbo builds up in the intercooler to leak away thus showing low boost conditions. In addition, if the Turbo seals are worn the engine oil gets carried into the intercooler where it condenses out and eventually leaks out of the worn through holes and gets slobbered about over the engine. If the seals are worn then the bearings in the turbo may also be worn, if this is really bad then the turbine can jam against the sides of the housing, also causing lack of boost. I had this on my 2001 Smart which had just done 100,000 miles.
I would guess an over boost. Maybe someone has wound the turbo up that would most definitely cause the symptoms or maybe it's had a turbo and someone hasn't set it up properly so the cars getting too much boost. Or it could well be a sensor is seeing too much boost and getting upset. I think it needs plugging in and seeing what codes it's throwing. I could even have a Stevie wonder map that just throwing it off. I don't think it's a fueling issue as that would usually cause jerking and clearly the car does happily boost before the computer goes into limp mode.
from the behavior in the video - ecu (pcm) does have bad checksum so it turns off boost - fairly typical outcome of someone trying to get more power out of it and messing up as ppl are used to do this in winols and checksum for smart correctly really works in very old versions etc. also these smarts did have kinda inverted way of what the parameters and what the program is.
I had exactly the same issue with exactly the same symptoms, turn it off & back on & it's like nothing had ever happened,,,,,but this was happening to my citroen c4 grand Picasso 2.0 hdi,,,i know completely different engine but like i said exactly the same everything, it was the turbo pressure sensor in the intake pipe on the top of the engine on the hdi, i wouldn't know where it would be on a smart, if you can find it take it out & clean it with some carb cleaner, it will be thick with oily sludge!
LOL Hubnut at the beginning of the video i swear i thought you were going to say a bad word LOL seems like the Smart car was frustrating ! I've actually been looking to buy one as they are so cool looking and have to be better than my Fiat 500 ? Surely it cant be as bad as a Fiat lol On a serious note mine is for sale for £3 grand a 2013 Lounge in yellow with 84k on the clock but it seems i cant even give it away LOL
@@ChishanFipz well yeah that's why I bought it as it looks cute but they are so unreliable sadly 😥 and I have advertised it on fb marketplace and gumtree but no serious buyers so may just sell to we buy any car at a loss sadly
As before, check the manifold for cracks and have a look at the wastegate length. It’s behaving as if someone has wound on too much preload… If it’s showing not that many threads (2cm or less) start winding off the preload a few turns until it stops this behaviour. Simples.
If you were close to Coventry with it, I'd offer a code read with Star. I think they'd norice me sneaking off to Wales on roadtest with one of the diag computers 😅 Sorry, I know that doesn't help. I'll try & have a look at TIPs (common fixes database), see if theres anything that might help. Do you have a Mityvac or similar to see if the wastegate moves/holds vacuum? Might be helpful to see if the controller is switching, just a thought
IT may be that now that the vacuum system is hypotethically sealed the long ter fuel trims of the engine computer are very out of spec and you have to unhook the positive battery terminal and jumper it to the negative battery terminal for 20-Overnight to 100% drain the power out of the different comuters which will reset all fuel trim data. Worth a try since its free barring the fuel to transport you to the unit. You can use a jump cable but be sure to insulate the positive pole. Some times even factory computers are not even equipped to clear such problems fully.
I was just deciding I want a new small car, and my criteria were sub 1 litre, 3 cylinder, 2 doors... Smart was top of the list, but now thinking a Peugeot 107 might be a better choice... in Rallye livery with those oh so sexy white steel wheels!
Mismatched tyres can cause misbehaviour of traction control. I am sure that there will be an error code hiding in one of the ECU, needing a better scan tool to extract it.
That skinny vac pipe to the fuel pressure regulator, the replacement pipe, looked very floppy. Are you sure that is proper vac pipe? They are usually quite thick walled. Ordinary hose may collapse just like the old one. Smoke test on the vac pipes? You might be able to borrow one.
Given how many things can cause this (seems like a lot of things) i would look to getting it diagnosed by a specialist (cheaper in the long run!). Otherwise you could replace part after part and still not fix it though this experience does make for good TH-cam videos. It sounds like complicated specific diagnostic software is needed to find the fault. Your average code reader sadly can't for these. I have an Icarsoft one thats much better for bmw/mini. Maybe something similar available for mercedes/smart?
My Insignia did this was the waste gate actuator causing an over boost and straight into limp mode to protect the engine but mine threw a code straight away what was wrong.
Modern cars hate weak batteries, both my Japanese Mitsubishi Diesel and LR3 Discovery would throw weird codes or go into limp mode with a weak battery and that Smart battery sounded weak.
I had a VW pissat that did this all the time , bloody dangerous when on the A34 then going into limp mode , once you restarted it, it would be ok again, I tried all sorts but ended up scraping the old girl , the car was on its last legs
Worm drive clamps that are a bit too long are great. For Medieval doctors that is, to open up veins next time you work on it. Ask me how I know. Best to all Hub Nutters from Australia
It's going into limp so don't assume it's a low boost issue, it could well be an over boost issue. You really need to know what fault code is being flagged. If you have a traction light I'd also have a look at the fear reluctor rings as they rot away & give inconsistent wheel speed measurements. You could prove this by unplugging the rear ABS sensors & seeing if it will drive ok & not put the engine into limp / reduced power (it will recognise a circuit fault for the sensors & disable the ABS).
Also bear in mind if you're using a generic code reader they only look for emissions related issues (which would also be generally accompanied by a check engine light). Other faults which are non emissions related don't have to be legally reported so generally aren't, especially true of MB. The oem diagnostic kit would look for all faults both OBD mandated & manufacturer specific.
There was a chap who looked just like you, driving a smart car just like yours, on the M5 between Bridgewater and Taunton, either yesterday or day before. I am guessing it wasn't you.
how many miles has it done? because it looks like a first gen smart to me, the engines in First gen Smarts are only good for about 84 thousand miles then the engines usualy need a full rebuild
i would think that the reference pipe that went soft on the fuel pressure regulator is a bit of a clue , could it be not compatible with petrol by any chance , petrol that shoud not be there and makes it doubtful that the fuel pressure regulator is any good... if your driving down the road and the boost pressure inside the engine exceeds the fuel pressure outside the engine then it becomes impossible to inject fuel into it and you konk out. i would vacuum test the fuel pressure regulator, even if its just a bit of clear tube and your mouth . next, when was the last time that poor thing had a fuel filter? it could be that simple
When you said about the one way valve stopping boost getting into the crankcase... it makes sense why the car goes into limp mode as it's trying to stop damage done to the engine
It's possible it could be the boost sensor ... I would have thought you would have had a code, tho 🤔 you are probably going to have to check all the vac pipes unfortunately 😕
Please don't rev the engine just before switching off, the oil supply to the turbo stops when the engine stops.....but.....the turbo is now spinning very fast WITHOUT an adequate oil feed.....this is NOT good for it. I got 220k on my allroad (turbodiesel) and according to many, the turbo should be dead by now......haha, but I lets the enjin idle fur 'alf a minute (minimum!!) afore I shuts it down, see.....
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A better scan tool might be helpful- might show more codes, and live data such as commanded vs actual boost pressures.
Or rather a cheaper tool. In other words a cheap OBD2-Bluetooth thingie (ELM327 clone which more or less everyone is), and the free version of the Torque app on any Android device. With that it's easy to have graphs for all relevant sensor values and desired values, and have a look at this while driving, and see what happens when the car gets upset.
Haven't seen the video where this was actually yet, but in general I would say that any turbo car might end up in limp mode if air flows the wrong way or in the wrong quantities. In particular the switch over from the intake having vacuum to being pressurized is the hardest part for the computer to handle, and it has to make assumption that things work correctly. If there is some air/vacuum leak the result will be that the O2 sensor (before the catalytic converter) will tell the computer that the air/fuel ratio is off, and the computer will realize that it can't keep the air/fuel ratio correct and thus it disables the turbo until you turn the ignition off and on again. This usually happens within a specific RPM range. Fun fact: at least on some cars you can turn off and on the ignition while in gear. Just let off the throttle before doing that and you won't feel any jerkiness when the engine restarts. Saves a bit of wear on the starter and whatnot.
Hi Ian. I'd have a look at the wastegate actuator. However, if the battery has been flat for a while, get it cleared by someone further up the food chain! Good luck
Had the same bother with mine drive along a few hundred yards then abs light would flash then into limp mode cracked rear abs rings
We had one of these in Canada. On purchasing it had no boost, which was a leaking induction pipe after the turbo. Then a few years later we had an intermittent no boost issue. This turned out to be an EGR valve sticking. Removing it and tapping it fixed it for awhile, but eventually we replaced the valve.
The symptom you described with the ABS light coming on, then a reduction in power, is suspiciously similar to a problem I've just has with my Volvo XC60, which turned out to be a faulty ABS sensor on one of the rear wheels. The sensor was telling the ABS/ESC software that a wheel was spinning when it wasn't and therefore that power should be cut to the rear axle. However, in the Volvo's case it was 'smart' enough to realise it was a fault and would disable the entire ABS/ESC system and allow you to drive the car normally, albeit with an instrument display lit up like a Christmas tree!
Looks like it's over-boosting and then going into protected mode. You're not in the lower gears long enough for the pressure to build up, so I think that's why you're seeing it in 3rd gear. You could try easing through the gears to 4th and then flooring it, confirm that it's boost related and not any other sensor related madness, like wheel speed mismatch etc. Does it have a wastegate, and can you actuate it - by hand, spanner or vacuum pump? If it can't bleed excess boost then it will have a wee fit and not want to play any more. Good Luck Ian, you will sort it.
My guess is either turbo pressure relief valve sticking/stuck or MAP sensor giving flase readings (but not far enough out of scale to give a code).
I had the same issue and it turned out to be the cycle valve/ turbo pressure relief valve. Apparently they are also available on VW and BMW and are cheaper and easier to source. More info on Evilution.
The diagnostic software these need is Mercedes STAR. I know S2Smarts in Leighton Buzzard has it but don't know if there's a place closer to Wales. I know from bitter experience not to let these get within 50 miles of a Mercedes main dealer, the one near me resented the fact they had to touch Smarts and resented even more when my Smart Roadster was getting more attention from their customers than anything on their showroom floor. btw Rob at S2smarts is a top bloke and a real enthusiast, I don't know if he still has it but he used to have one where he'd thrown a subaru turbo and a whole bunch of other subaru parts at it to make 150hp.
I purchased my Smart ForTwo a few days before HubNut acquired his and mine was serviced at S2Smarts shortly before I purchased it! Small world!
Is that the system with a massive control unit? With all the cables it needs a rucksack to cart about? I bought mine to fix a 1997 mercedes 200 as to get that out of limp mode you can only use the diagnostics unit, and it was very user unfriendly but got the job done.
The current star isn't too bad for cabling, it has been known to work wirelessly if you aks it nicely, offer it sweeties and the planets align (use it to do software updates wirelessly at your peril though...).
Yep I would phone Rob at s2 smart,
Its not merc star, its xentry or openshell. Not sure which century your from? STAR was retired along time ago.
Loss of boost will most likely be the waste-gate valve (on the turbo). Is there a vacuum pipe to it? Does it leak? Does the diaphragm it actuates leak? Is it electrically controlled? Other than that, the valve itself might be seating too loosely for one reason or another. Perhaps the linkage is past its best? Or the return spring within is weak?
Yeah I conccur with others. Maybe look at getting a scan tool focused towards Mercs and German stuff that has the facility to do live data logging.
Be useful to get the codes or see live running data on boost pressures, however, my money is on an overboost which is happening when you floor it, leading to limp. In this case, likely worth checking the wastewater actuator and associated plumbing, as well as your boost pressure sensor.
At the end of this video I was reminded how my poor 1971 Peugeot 304 Coupé ended: as a card box storage in a dirty shed... Good luck with the Smart!!! See you soon --- Martin
Working on an MGF/TF is like skipping around in a cathedral compared to the Smart engine bay!
I've probably made this comment about five times since you bought the Smart to no avail, but it's almost certainly boost control. The plumbing to the wastegate actuator is complex with five hoses and the boost control solenoid (aka cycle valve) is prone to sticking. Check the plumbing on the Evilution site. The cycle valve is mounted on the steel bracket that supports the turbo air inlet pipe (aka TIK pipe). Another, more remote, possibility is someone has tightened up the adjustable wastegate linkage too much so the actuator doesn't have enough travel left to open the wastegate fully. It's also possible, though unusual, for the actuator itself to fail.
The crankcase vent valve failing open doesn't cause enough boost loss to be noticeable and I've never seen the ECU going into limp mode from this, though it certainly can cause oil leaks.
Have another Cycle Valve on the way and I'll check the pipework when it arrives.
@@HubNut I don't know. This guy doesn't sound like he knows what he's talking about.
@@joesullivan-y9rwhy?
Eurn doesn't listen to advise if he can make another monetized video, interestingly he is still spamming his videos on autoshite without contributing to forum fees but those lentils dont pay for themselves, why not tell your story on modgate on the dark wob?
@@johndoe-lo1yx What are you on about? Who's Eurn?
I know the feeling Ian with older car 'foibles' that it quite often becomes a process of elimination by replacing bits and bobs so if anything they can narrow that root cause of the problem without a sky high bill for a 'specialist' to diagnose who after all might not be able to fix an issue. A small leak in a hose can throw a more modern (circa 2000) engine easily so I agree with the approach you are taking. With so many breather pipes and valves everywhere it's a pain, more so where access is very restricted. Many thanks for sharing. Hopefully other Smart owners can help out as you mention.
Id be checking the actuator on the waste gate is working and not seized. As for the traction light, they have a yaw sensor on them over exuberant driving pops the traction light on (I believe to aid stability) . An old trick was to turn the thing 90 degrees to "turn it off"...
My 2005 Astra Diesel did exactly the same thing, and despite multiple garage visits, never able to get to the bottom of it. Ultimately was consigned to being a parts car
Your first car that does its own Ptchooo to end the fun!
When my 451 was messing around and doing all kinds of weird behaviour after a major service, it turned out to be a piece of rust on one of the Abs sensors. All was fine after that was cleared. Dry joints in the computer box also cause problems. There's a video somewhere on TH-cam the explains that better, though for 451 so not sure if the 450 has similar problems.
I had a similar issue with my 2009 Mercedes C200 where my traction control light came on and I lost power if I went above a certian speed. If I turned off the engine and restart it the problem would be gone until I get up to that same certain speed. It was a split intercooler hose. A brand new genuine Mercedes part from a local dealer cost me just over £60 and it fixed my problem. If you have a split intercooler hose there will be oil where it has leaked out as intercoolers will have some oil inside them.
Had a similar issue with my first E320. People online said to change the turbo actuator which I did multiple times and it didn’t fix it. I took to a garage with STAR and they couldn’t fix it. Drove it like it was in the end. Turning it off and on again always cleared the fault temporarily.
I can honestly say Thanks I have been fancying a Smart for some time but seeing your videos has put me off permanently.
My mate had one and the inability to do the most simplest things like change the spark plugs was so bloody awkard we became adept and removing the engine reasonably quickly - we even considered trying to make it 'quick release' we were doing it so often. The trouble is they are such great cars when ok you push yourselves into it sometimes almost too far, and that's why they are a no from me too
It's an 18 year old car. I've also got a 2006 450 and it's been faultless.
@@PaulabJohnson nothing at all to do with the age, I think they are superb little cars - it's just that they did not think at all about making simple maintenance easy. Shouldn't have to take the engine out to change a spark plug.,
Not the age that's the problem, my car is 20 years old, it's the total lack of access.
@@ChishanFipz I don't disagree. Unfortunately it's a trade off when fitting a small turbo charged engine into a compact city car - space will always be at a premium.
The trick with these cars is to use a specialist who only works on Smart cars as they are so idiosyncratic - it's not really the type of car you want to be working on at home.
Saying that, there are plenty of 'normal' sized modern cars where even simple tasks require significant engine disassembly = unfortunately the days of stripping down the engine of your cortina on the drive (like my dad did) are long gone.
Cars are increasingly seen as just another white good nowadays.
Continued good luck to the ongoing saga of the Smart car …. Keep the faith 💪💪💪
Might be worth a quick visual inspection of the abs rings on the driveshafts. They tend to rust and the teeth breakdown, which confuses the ABS. This usually results in an ABS/Traction control warning. In the early stages, it seems to only kick in when you boot the throttle. I had this issue on my roadster, although it didn't cause the car to fall into limp mode. Even if this is not the cause of your problem, it's still worth checking as they will eventually need replacement.....
Its either an under boost or an over boost. But it seems more like an over boost. Not too sure on Smart car's but I when the VW Audi goes into limp mode it disables the traction control therefore the light comes on. I would guess it points to boost control valve or the turbo actuator something along those lines. Good luck 👍
Exceeding the max boost (18 psi?) would trigger the limp mode on my 450 cdi. Another possible cause is a cracked reluctor ring which throws off the wheel speed sensor that indicates one wheel is turning much faster than the other. Also had limp mode caused by a bad connection on the egr. I got a troble code indicating an egr issue, but seeing as I had blocked off the egr I knew it had to be the sensor connector and not a plugged up egr.
Check the rear ABS rings on the axles. If these are corroded the traction control will go a bit wild and potentially limit power.
For researching boost or vacuum leaks, investing in a smoke machine is worthwile.
Hi Ian. From memory you can turn the traction control off on these. I believe it is one of combination things you have to press buttons and switch things! I remember switching it off to get up a fairly steep road in the snow one year. BTW they are great in the snow as they are so light. All the best.
You'd have thought a code reader would help but I know from experience that they're not all created equal - what BMW DIS and INPA find over some third party readers is quite surprising. When I saw you struggling to latch the hood on the Smart it reminded me that I need to adjust the bonnet catch on the Yaris - yes, it lives again! New radiator, new maniverter and it runs great. No pong of exhaust fumes any more. How the garage got those rusted manifold bolts out I'll never know.
I also have the traction/abs light come on (well flash actually) every now and again, but in my insurance it doesn't affect power or boost. Not sure this helps at all but all the same..
Hi check the turbo wastegate not seized shut and is the pipe on and air tight to the wastegate 👍
The ESP (traction control) light flashes at the drop of a hat on the 2 Smarts we've had. It doesn't seem to affect anything. In fact, sometimes, the traction control sometimes activates on tight roundabouts, but not always, despite the light flashing.
Have a look at the sensors, plug it in to a diagnostic machine. We had issues with our 450 smart dealership charged us a fortune for a new crank sensor
Absolutely brilliant video Ian miss hubnut ❤👍 hope you manage to sort your problem with her Ian brilliant
Possibly a sticking waste gate actuator? Not sure of the set up on a Smart but would be interesting to know as I'm looking to get one myself for commuting
As my earlier comment you can buy the replacement rings for driveshaft loosen off the centre nut and shocker the side it's cracked you can see the crack in the ring that needs replacing once you've loosened everything off on that side put a long bar the longer the better into the end of the axle and pull you can wangle the driveshaft end out removed the old ring clean off all the rust where it goes back on cos that what cracked the ring in the first place tap the new ring back on in original place and rebuild
You really need to see live data but I’ve no idea what kind of diagnostic gear would give you that. It has to be electronic / electrical as opposed to something physical because it looks like when it’s right, it works really well. If I had to guess I’d say boost control solenoid / circuit? It may be over boosting and shutting itself down to protect itself but the traction control light is a mystery!
An engine management fault will often bring up a traction control light too.
This is because the engine management system is interlinked with the traction control system.
When the traction control kicks in, it can reduce engine power, as well as braking individual wheels.
One fault in a modern car will often light up the dash like a Christmas tree. Especially in Peugeots.
The HubSmart is actually a work of genius, as it is very roomy (for two), well-built, practical and economical. The ultra-safe and solid Tridion body shell does not seem to have any of the rust issues that affected many Daimler Chrysler bodies of the day. However, the (Soft-tip?) gearbox spoils things. We once hired a purple/silver one in Lanzagrotty over 20 years ago now. I remember this car tended to dive between shifts, and losing almost all momentum going up hills because it took the Smart Car too long to find the gear it was supposed to be in.
Oh they rot. Reckon this one will need welding before too long.
Limp mode followed by key-off then key on makes me think that it's a parameter out of range leading to ECU invocation of limp mode. A bit like worn injector issues on Renault DCi's for example.
Bleep bloop! I don't have anything to add, but I did quite enjoy seeing this from the other perspective in the Short the other day. 😄
A trip to Smart- TECNIC in Birmingham, maybe... or you may be on a long time 😄
I had a similar issue on a discover 300tdi and fly by wire throttle. The turbo waste gate had seized and at 3000rpm the car lost loads of power, no light or limp mode because it was 1997 car. I suggest you use an OBD on live data to see turbo boost or manifold pressure, ODB doctor on your phone with a suitable Bluetooth ELM327 worked fine for me, and watch the boost as you accelerate, I think you can record too. I am sure the interweb will tell you what max pressure should be. What I did to cure mine (it worked and I sold the car 5 years later still working perfectly) was; Spray the wastegate pivot (where it goes through the cast iron shell of the turbo) with penetrating oil and leave it over night. Then I exercised it, I used an adjustable spanner (difficulty to get at on the Disco as the alternator is very close, so battery disconnected). Obviously the oil goes as soon as the turbo gets hot, but for the first day it was fine. The I exercised it (using some oil for the first few time) every day for a week before I used the car, then I dropped down to once a week. It never stuck again, I actually made up a bar with a slot in the end so I could poke it through the turbo and the slot went over the wastegate actuator rod (just behind the adjuster nut) and I would move it a few time before I drove the car (only needed it once a day). You may also find that the ABS light flashing is a warning for something nothing to do with the brakes, I suppose they use it so you take the car to a garage to get it checked. When the boost control actuator stuck on my Golf GTTDI the turbo melted in less than a 100 yards, so what your experiencing can been seen as a good thing.
Seems reluctant to turn over of half a second as is the battery is low, but they bursts into life no problem.Seemed to do it even from warm during your drive!
Seems pretty standard. The Smart Roadster did it too.
Cracked traction control ring on rear drive shaft
A neighbour's Audi TT had a PCV valve fail open. With a turbocharged engine this had the expected result and oil was forced out of every seal and some other places. They finally realised something was wrong when it started misfiring after idling when hot due oil getting into one cylinder and fouling the plug, but by then the engine was an oily mess. They dealt with it by selling it.
That's one solution I guess.
The timing sounds like it's late when you start it. It sounds like the knock sensor first cut timing, then boost at X bar of pressure, and it isn't putting timing back in when it's supposed to. Cutting off the ignition resets it, so it's most likely a weak sensor (or more than one) instead of a bad vacuum line.
They often sound like that when starting. The Roadster was the same.
10:17 ominous words, just casually thrown in, Ian? I see another well-deserved move/retirement coming on for one fleet member, and increased peace of mind for yourself ... unless you're already thinking of something else on 4 wheels ...
I suspect the Berlingo's days are numbered...
I feel your pain Ian.
Intermittent issues associated with one or more sensors are so frustrating
Maybe off course here, the SAM unit under the dash have probs with dry solder joints that causes many strange faults, they're affected by water damage too, the windscreen seals are not the best especially if you reside in a wet climate, does it rain in Wales?
Very rarely...
I'd try and get the battery to its full running voltage. That can skew lots of readings and generate weird faults.
If it isn't the plumbing/wastegate, then it may be that the turbo deactivation is part of the Limited Operation Strategy. It detects an engine problem and so does whatever it can to minimise the risk.
Did i pass you and Ellie going south on the Aberystwyth road near Brynhoffnant on Wednesday morning 😊
Yes, we were off to refuel Elly in Brynhoffnant.
Have you checked turbo hoses for splits, perhaps a smoke test.
Maybe check the ECU connectors and while doing that, give them a good spray with contact cleaner. My Citroën C2 did the weirdest things that literally no-one could explain at one point. We had the car at independent mechanics, Citroën specialists, even the agents did not have answers for me. After some inspection of my own, it turned out to be corroded pins on the ECU connectors that were related to the central locking, immobilizer, and fuel pump.
Those pins are incredibly thin so the slightest bit of corrosion causes them to send strange messages... My dad and I ended up having to solder the wires directly to the circuit board instead of using the pins of the connector again because the 3 pins in question were completely corroded.
This fixed all of the weird problems we had. Maybe it helps in your case as well...
What a car, should get Pete Coupland over for a look, definitely the type of car that needs a decent scanner to find the faults. Also looks a little low on the front 😪
Hi Ian, Don't know if this is any help. I have maintained my wifes 451 cabrio for the last 14 years myself. I know the later ones have a Mitsubishi engine, but notice some similarities. Your car is in urgent need of a service and I would find out if there is indeed excess crankcase pressure. If you work through the pipework on the whole breather circuit including the intercooler, I suspect you will find a valve or similar blocked with oil residue (mayonaise),or yet another pipe split. Sometimes if you cannot clear a code or get the triangle of doom, disconnecting and reconnecting the battery after a few minutes, sometimes resets the whole thing. The dealers charge a fortune for a code read and suspect you will struggle to find a Benz dealer that will work on it. If yours does not have a sump plug, I would suggest removing the sump and cleaning it as well as the oil strainer as part of a service. 451's recommend Mobil 1 which I consider a waste of money. I change my wifes Smart oil yearly and change the air filter as it lives in a very hot and dusty world. Decent oil is worthwhile such as MB 229.52 which if bought from the internet can be under £60 for 10 lts. I use this in my Dacia Sandero diesel as well and its excellent and produces very little mayonaisse which can be a problem if the car has been used for short journeys creating condensation which does not burn off. You also have twin spark plugs on the earlier smarts as well. Hope this helps. I would like an earlier Smart car myself.
The turbo hasn't got electronic actuators on it. If it doesn't it might mean a new turbo. Had to have my turbo replaced on my car recently for that reason.
It will loose boost Ian if it goes into limp mode. Maybe air flow mass sensor
One thing to do is to drive it with a light foot, don't go far into the boost, if at all. Can you drive this car on just the edge of the boost and see if it also throws a fault? You like to drive this car rather spiritedly, and I'm wondering if it's a matter of just kerbing your enthusiast side long enough to actually find out if the turbo is the sole reason it's going into limp mode. I really hate limp mode; our Turbobrick had a transmission shifter position sensor that needed cleaning that was repeatedly shifting the car into second and limp mode.
I'm quite fondling the idea of having one of these cabrios just to use in the city and have a breeze when the heat goes under 30 degrees (hot country here 😂), don't like the way they drive, but love the way they just are... they are still some of a premium here in brazil.. so not so very cheap to just go and get one, but at least the majority is low mileage and well maintained.
Here's my guess. ABS/speed sensors getting confused so going into limp mode. Might not show up as an engine code, as not strictly an engine issue. Fingers crossed you fix 'er.
Smart cars of this vintage have a habit of wearing through the intercooler, the frame that the intercooler is fixed in wears away the plastic. This causes the of air pressure that the Turbo builds up in the intercooler to leak away thus showing low boost conditions. In addition, if the Turbo seals are worn the engine oil gets carried into the intercooler where it condenses out and eventually leaks out of the worn through holes and gets slobbered about over the engine. If the seals are worn then the bearings in the turbo may also be worn, if this is really bad then the turbine can jam against the sides of the housing, also causing lack of boost. I had this on my 2001 Smart which had just done 100,000 miles.
I would guess an over boost. Maybe someone has wound the turbo up that would most definitely cause the symptoms or maybe it's had a turbo and someone hasn't set it up properly so the cars getting too much boost. Or it could well be a sensor is seeing too much boost and getting upset. I think it needs plugging in and seeing what codes it's throwing. I could even have a Stevie wonder map that just throwing it off. I don't think it's a fueling issue as that would usually cause jerking and clearly the car does happily boost before the computer goes into limp mode.
from the behavior in the video - ecu (pcm) does have bad checksum so it turns off boost - fairly typical outcome of someone trying to get more power out of it and messing up as ppl are used to do this in winols and checksum for smart correctly really works in very old versions etc.
also these smarts did have kinda inverted way of what the parameters and what the program is.
Have to admit the Smart is a cute little car, you will get to the bottom of the issue Ian.
I had exactly the same issue with exactly the same symptoms, turn it off & back on & it's like nothing had ever happened,,,,,but this was happening to my citroen c4 grand Picasso 2.0 hdi,,,i know completely different engine but like i said exactly the same everything, it was the turbo pressure sensor in the intake pipe on the top of the engine on the hdi, i wouldn't know where it would be on a smart, if you can find it take it out & clean it with some carb cleaner, it will be thick with oily sludge!
Sounds like your turbo actuator needs adjusting/tightening. Or you might just need to replace that actuator.
LOL Hubnut at the beginning of the video i swear i thought you were going to say a bad word LOL seems like the Smart car was frustrating ! I've actually been looking to buy one as they are so cool looking and have to be better than my Fiat 500 ? Surely it cant be as bad as a Fiat lol On a serious note mine is for sale for £3 grand a 2013 Lounge in yellow with 84k on the clock but it seems i cant even give it away LOL
that would be gone if you were down here in kent - girlies love them
@@ChishanFipz well yeah that's why I bought it as it looks cute but they are so unreliable sadly 😥 and I have advertised it on fb marketplace and gumtree but no serious buyers so may just sell to we buy any car at a loss sadly
Is the 500's engine a 4-pot petrol, Multi-Jet (my favourite!), or Multi-Air?
As before, check the manifold for cracks and have a look at the wastegate length. It’s behaving as if someone has wound on too much preload… If it’s showing not that many threads (2cm or less) start winding off the preload a few turns until it stops this behaviour. Simples.
If you were close to Coventry with it, I'd offer a code read with Star. I think they'd norice me sneaking off to Wales on roadtest with one of the diag computers 😅 Sorry, I know that doesn't help. I'll try & have a look at TIPs (common fixes database), see if theres anything that might help. Do you have a Mityvac or similar to see if the wastegate moves/holds vacuum? Might be helpful to see if the controller is switching, just a thought
IT may be that now that the vacuum system is hypotethically sealed the long ter fuel trims of the engine computer are very out of spec and you have to unhook the positive battery terminal and jumper it to the negative battery terminal for 20-Overnight to 100% drain the power out of the different comuters which will reset all fuel trim data. Worth a try since its free barring the fuel to transport you to the unit. You can use a jump cable but be sure to insulate the positive pole. Some times even factory computers are not even equipped to clear such problems fully.
The traction control light may be related to the gearbox, Especially if it has a speed sensor in it. Or joy of joys an intermittent ground fault.
another great video has always Ian and Carly miss/mrs hubnut and hublets and hubmutt 👍
I was just deciding I want a new small car, and my criteria were sub 1 litre, 3 cylinder, 2 doors... Smart was top of the list, but now thinking a Peugeot 107 might be a better choice... in Rallye livery with those oh so sexy white steel wheels!
If you get a post 2007 smart they have mitsubishi engines that are a bit less prone to problems.
Get a Toyota Aygo MK2 2014-2016 zero tax
107 is a good call but watch for rot, especially around the rear.
Hi Ian, might it be better to just scrap it or sell it for parts.
Kind regards Andy
Mismatched tyres can cause misbehaviour of traction control.
I am sure that there will be an error code hiding in one of the ECU, needing a better scan tool to extract it.
That skinny vac pipe to the fuel pressure regulator, the replacement pipe, looked very floppy. Are you sure that is proper vac pipe? They are usually quite thick walled. Ordinary hose may collapse just like the old one. Smoke test on the vac pipes? You might be able to borrow one.
Cycle valve or incorrect hose connections. I’m sure it’s been noted before, but these are classic symptoms of valve failure or poor operation.
Given how many things can cause this (seems like a lot of things) i would look to getting it diagnosed by a specialist (cheaper in the long run!). Otherwise you could replace part after part and still not fix it though this experience does make for good TH-cam videos. It sounds like complicated specific diagnostic software is needed to find the fault. Your average code reader sadly can't for these. I have an Icarsoft one thats much better for bmw/mini. Maybe something similar available for mercedes/smart?
Main issue is I can't get it to a specialist while it isn't running properly...
Think you need the manufacturers scan diags, there's no way it's going into limp mode and not logging something somewhere, my guess is sticky EGR
My Insignia did this was the waste gate actuator causing an over boost and straight into limp mode to protect the engine but mine threw a code straight away what was wrong.
It's over boosting by the sounds of it, probably an air leak or a seized actuator on the turbo, have you checked if the arm moves???
Not yet. Will get the bumper off and have a look.
Modern cars hate weak batteries, both my Japanese Mitsubishi Diesel and LR3 Discovery would throw weird codes or go into limp mode with a weak battery and that Smart battery sounded weak.
Battery is fine. Brand new and fully charged.
Bad earth or replacement starter getting sad...
I had a VW pissat that did this all the time , bloody dangerous when on the A34 then going into limp mode , once you restarted it, it would be ok again, I tried all sorts but ended up scraping the old girl , the car was on its last legs
Worm drive clamps that are a bit too long are great. For Medieval doctors that is, to open up veins next time you work on it. Ask me how I know. Best to all Hub Nutters from Australia
A dry joint/bad connection in the ECU maybe?
It's going into limp so don't assume it's a low boost issue, it could well be an over boost issue. You really need to know what fault code is being flagged. If you have a traction light I'd also have a look at the fear reluctor rings as they rot away & give inconsistent wheel speed measurements. You could prove this by unplugging the rear ABS sensors & seeing if it will drive ok & not put the engine into limp / reduced power (it will recognise a circuit fault for the sensors & disable the ABS).
Also bear in mind if you're using a generic code reader they only look for emissions related issues (which would also be generally accompanied by a check engine light). Other faults which are non emissions related don't have to be legally reported so generally aren't, especially true of MB. The oem diagnostic kit would look for all faults both OBD mandated & manufacturer specific.
There was a chap who looked just like you, driving a smart car just like yours, on the M5 between Bridgewater and Taunton, either yesterday or day before. I am guessing it wasn't you.
Not guilty!
Sometimes it is difficult to find faults especially if there are no codes identifying
is the throttle a fly by wire, it sounds like that to me
how many miles has it done? because it looks like a first gen smart to me, the engines in First gen Smarts are only good for about 84 thousand miles then the engines usualy need a full rebuild
Checked the actuator on the turbo not sticking?
See latest Smart video.
It was given to you for a reason lol
i would think that the reference pipe that went soft on the fuel pressure regulator is a bit of a clue , could it be not compatible with petrol by any chance , petrol that shoud not be there and makes it doubtful that the fuel pressure regulator is any good... if your driving down the road and the boost pressure inside the engine exceeds the fuel pressure outside the engine then it becomes impossible to inject fuel into it and you konk out. i would vacuum test the fuel pressure regulator, even if its just a bit of clear tube and your mouth . next, when was the last time that poor thing had a fuel filter? it could be that simple
Probably overboost… sounds way to aggressive on acceleration. goes into limp mode to protect engine. Check boost controller and pipes to it.
When you said about the one way valve stopping boost getting into the crankcase... it makes sense why the car goes into limp mode as it's trying to stop damage done to the engine
Sticky actuator/motor/solenood
It's possible it could be the boost sensor ... I would have thought you would have had a code, tho 🤔 you are probably going to have to check all the vac pipes unfortunately 😕
Like the smart
Please don't rev the engine just before switching off, the oil supply to the turbo stops when the engine stops.....but.....the turbo is now spinning very fast WITHOUT an adequate oil feed.....this is NOT good for it. I got 220k on my allroad (turbodiesel) and according to many, the turbo should be dead by now......haha, but I lets the enjin idle fur 'alf a minute (minimum!!) afore I shuts it down, see.....
Good luck
I don’t know SMART cars. But any car I’ve seen do that just needed the throttle body cleaned.