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Symptom: Car randomly shuts off while driving, so far only when engine is up at working temp. Some times car can be started right after it shut off, at times it can be started after ~10 minutes.
This weekend for example I drove 50 km one way, car shut of after 27km, started right up and went well the rest of 23km the way there, on the way home it went just fine.
Other days the car refuses to start, always when the car is warm, never been an issue with a cold start. Whilst it refuses to start it has so far paid off waiting 30 - 90 minutes before it finally starts.
All whilst not generating an engine lamp, although there are fault codes, listed below.
Fault Codes read with Autocom (Photo in attachments):
Other observations:
The extra water pump by the coolant resourvoir is whining at times.
Prior to this issue the car would go into limp mode of going uphill in speeds above 115 km/h where it would complain of P0252 (Injection Pump fuel metering control A Range/Performance(Cam/Rotor/Injector)
I’ve performed a leak test of the injectors and gotten even values on all injectors.
Parts I’ve changed and done somewhat recently:
Fuel filter
Fuel filter holder
Camshaft sensor (Year ago and didn’t correct first fault code)
Less related stuff but in case I’m naive I’ll list them
Fuel return line from the injectors
Charged both batteries
Handbrake rear both
Shocks rear
Changed my oil
Had Mercedes service gearbox
Brake pads
Windshield wipers
I’m going mad trying to troubleshoot this, any help or idea to throw at me would be apprechiated.
Assuming the fuel pump is mechanically driven by the engine (old diesels had this) the engine stops only when fuel delivery stops. There is no spark to worry about and all possible reasons for losing the spark.
So, is there a fuel valve that is controlled electronically that is “flaky” and randomly closes? Could it have a coil that shorts/fails when engine hot?
If I had to guess, your high pressure fuel pump (which is normally driven by your camshaft) is your root cause. If it's about to seize it would explain your camshaft/crankshaft correlation codes, the fuel metering valve code and the sudden stoppage. I think it would be smart to take it out to inspect or at least try to run the car with a real-time scanner connected to monitor how is your rail pressure going behaving.
EDIT: By any chances the issues started or gotten worst after you replaced the fuel filter?
Last edited by Andre Cateb; Aug 22, 2024 at 01:54 PM.
First off, sorry for not getting back to you, I lost my temper and got a company car for 1 month (Tesla, yuck) and then drove my dads clio
I've driven the Merc for a week now, mostly been fine but I've had 2 occasions where it shut off.
- First time it shut off on the highway, I was driving ~110km/h and it shut off, but it started again before I was at a full stop and was fine to keep driving
- Second time happend yesterday on the highway ~ 130km/h and it shut off, this time I had my iCarSoft with me and began troubleshooting.
Whilst not starting (Data from second occurance, video on it as well)
- Rail Pressure = 450 - 477 bar
- Injection Quantity = 0mg/Hub
- Power consumption of component Y94(Quantity control valve) = 146 - 151 mA
- Power consumption of component Y74(Pressure regulating valve) = 650 - 675 mA
- Status of synchronization between crankshaft and camshaft = Synchronized
- Low fuel pressure = 4,00 - 4,09 bar
- On/off ratio of component Variable fuel pump = 93 - 100%
- Fuel pump = Avtivated
I must admit I am lost as to what to change, maybe there's gunk somewhere? Due to the rail pressure I doubt it's either one of the fuel pumps but rather gunk or faulty valves. Image of leak test performed, its 4 cyl hence 2 empty.
Excellent job circling all around yout issue. No one could have done this better.
Your diesel likes to quit only when hot, couple sensor codes found.
> The only question I have is:
are these codes CURRENT or STORED??
What happens after you clear faults, come back as STORED ??
> The combination of weird CPS + Lambda faults read like... "oil-in-harness".
Disconnect batteries and check your ECU connectors ... dry vs. oily?
> As far as correlation code...
you have new Cams sensors (both intake/exhaust?)
VVT Gear ok ?
then crankshaft sensor ??
I don't think your fuel pump is involved in this chaos. ECU has enough reasons to quit with severe timing fault.
Hi, seems your exclusion is correct regarding the fuel pump.
Of your question whether current or historical I've sent a reply above which shows all fault codes with the requested marking with iCarSoft Tool.
I've cleaned up a fair amount of connectors, I've one oily one I haven't taken care off here:
If I had to guess, your high pressure fuel pump (which is normally driven by your camshaft) is your root cause. If it's about to seize it would explain your camshaft/crankshaft correlation codes, the fuel metering valve code and the sudden stoppage. I think it would be smart to take it out to inspect or at least try to run the car with a real-time scanner connected to monitor how is your rail pressure going behaving.
EDIT: By any chances the issues started or gotten worst after you replaced the fuel filter?
Hi, thank you for your reply.
High pressure fuel pump seems fine, according to my post 2 above this one where I've read live data and seen good rail pressure.
Possible that the fuel valves are the root for this.
Good question about the fuel filter, I've had a few issues a while back with the car going into limp mode which is what prompted me to exchange it for a new one to begin with, I'd say that didn't solve it but after everything I've done since then (most bleeding air from the fuel lines (4 times to make sure)) that limp mode issue has been gone (appeared when driving 120km/h, usually on a steep hill upwards).
The new fuel filter is from Mann-Filter which has an OEM Part Number of "651 090 15 52".
Assuming the fuel pump is mechanically driven by the engine (old diesels had this) the engine stops only when fuel delivery stops. There is no spark to worry about and all possible reasons for losing the spark.
So, is there a fuel valve that is controlled electronically that is “flaky” and randomly closes? Could it have a coil that shorts/fails when engine hot?
Hi, very thankful for everyones replies here, yours included of course.
As per my live data 3 posts up it seems fuel delivery stops but rail pressure is fine, both from low and high pressure fuel pumps.
I susepct a fuel valve at this point, the injectors (which I assume you meant by coils) seems to be fine according to a leak test and I cannot see any reason for it to short but that's of course not out of the question, I shall inspect asap.
I read your fault screens and watched your video...
Your Mercedes diesel dangerously quits while speeding ...
1st thing is I'd advise you stay out of high speed dangerous traffic situations. Don't drive this chassis around!
engine running...11.9V... low voltage !!
Looks like your engine has the "drained by driving" condition.
Learn to display voltage/current on main IC Display.
Report what the voltage measures under normal conditions.
Thank you once again!
I did not consider that at all, thanks for pointing this out, one thing to note is that that is with AC on which I believe should up the voltage due to the YOYO as I've read on a somewhat similar post.
Although it should be said that what you're seeing is a hot engine at idling which I deducted may prompt the voltage to be low once started but it's below 12V and I see the gravity of your point and agree.
Main battery has never been replaced during my 2.5 years of ownership, aux battery has been replaced about 2 years ago since Hill Assist didn't work and I measured low voltage, non oem battery.
To further validate your point I have gotten different dash situations when the engine stops responding, sometimes the lights on the dash light up and sometimes it doesn't.
I'll record the voltage when driving later on today, I try to keep myself only driving when there's light traffic
I look forward into speculating whether this could be the battery/alternator or some more in-depth issue.
Thanks
William
Edit: remove the image from the quote to keep things neat.
I think there are two good point to check next:
1. Your alternator output as your battery voltage with the engine on should be close to 14VDC even in idle.
2. Your rail pressure with the engine under load which should be close to 1.600 BAR.
Your low pressure fuel system seems to be fine, hence electrical fuel pump and fuel filter can be excluded. Based on knowledge from other diesel MB engines, I suspect your engine has two methods of controlling the fuel supply to the common rail; the fuel metering unit (which controls how much fuel is fed to the rail) and the pressure release valve (which "dumps" the rail pressure when needed). Is the issue is not related to the low voltage or a bad high pressure fuel pump, I would try replacing the FMU as it could be preventing fuel from going into the rail before going for a injectors replcacement.
Thank you once again!
I did not consider that at all, thanks for pointing this out, one thing to note is that that is with AC on which I believe should up the voltage due to the YOYO as I've read on a somewhat similar post.
Although it should be said that what you're seeing is a hot engine at idling which I deducted may prompt the voltage to be low once started but it's below 12V and I see the gravity of your point and agree.
Main battery has never been replaced during my 2.5 years of ownership, aux battery has been replaced about 2 years ago since Hill Assist didn't work and I measured low voltage, non oem battery.
To further validate your point I have gotten different dash situations when the engine stops responding, sometimes the lights on the dash light up and sometimes it doesn't.
I'll record the voltage when driving later on today, I try to keep myself only driving when there's light traffic
I look forward into speculating whether this could be the battery/alternator or some more in-depth issue.
Thanks
William
Edit: remove the image from the quote to keep things neat.
Hi, I realized I had my iCarsoft up measuring Voltage, not via the built-in Merc display, but when driving for about 25 minutes at 50km/h I had 14,45 Volts according to iCarSoft.
Whilst driving 100 km/h I had the same amount of Voltage, namingly 14,45 Volts.
Lastly when I got home and were at a standstill, i.e 0 km/h I had 14,43 Volts.
I think there are two good point to check next:
1. Your alternator output as your battery voltage with the engine on should be close to 14VDC even in idle.
2. Your rail pressure with the engine under load which should be close to 1.600 BAR.
Your low pressure fuel system seems to be fine, hence electrical fuel pump and fuel filter can be excluded. Based on knowledge from other diesel MB engines, I suspect your engine has two methods of controlling the fuel supply to the common rail; the fuel metering unit (which controls how much fuel is fed to the rail) and the pressure release valve (which "dumps" the rail pressure when needed). Is the issue is not related to the low voltage or a bad high pressure fuel pump, I would try replacing the FMU as it could be preventing fuel from going into the rail before going for a injectors replcacement.
Best!
Looking at my post 2 posts above this one it seems fine with the voltage whilst running and at a stand still after a drive.
I'm torn as what to troubleshoot, I got my shop 1 hour away so I'd love to purchase parts and bring these with me there and change what's needed.
We're getting sub 0 Celius degrees over here in Sweden now so I'd very much like being cozy in my shop performing the tests and replacements, plus the site where I order parts from offers a free return policy.
Supposedly I could buy a alternator, serpentine belt whilst I'm there, crank shaft position sensor, possible fuel valves and a battery?
I would really hate for it to be the high pressure pump :P
Hi, I realized I had my iCarsoft up measuring Voltage, not via the built-in Merc display, but when driving for about 25 minutes at 50km/h I had 14,45 Volts according to iCarSoft.
Whilst driving 100 km/h I had the same amount of Voltage, namingly 14,45 Volts.
Lastly when I got home and were at a standstill, i.e 0 km/h I had 14,43 Volts.
Unfortunately I haven't been driving these days.
do you know what current was associated with 14.4 V ??
Voltage is supposed to come down rapidly towards 12.6V away from 14.4V
Don't use cheap parts to replace good ones. 🤞
Last edited by CaliBenzDriver; Oct 15, 2024 at 08:31 PM.
Looking at my post 2 posts above this one it seems fine with the voltage whilst running and at a stand still after a drive.
I'm torn as what to troubleshoot, I got my shop 1 hour away so I'd love to purchase parts and bring these with me there and change what's needed.
We're getting sub 0 Celius degrees over here in Sweden now so I'd very much like being cozy in my shop performing the tests and replacements, plus the site where I order parts from offers a free return policy.
Supposedly I could buy a alternator, serpentine belt whilst I'm there, crank shaft position sensor, possible fuel valves and a battery?
I would really hate for it to be the high pressure pump :P
If you measure 14+ V there is no need to even think about the alternator. It is good. Change out that crank sensor as your symptoms point to that assuming a diesel engine has one, I think it does.
do you know what current was associated with 14.4 V ??
Voltage is supposed to come down rapidly towards 12.6V away from 14.4V
Don't use cheap parts to replace good ones. 🤞
I unfortunately don’t know the amps pulled at those times, I’ll start using the Merc Display as it displays both current and voltage if I’m not mistaken.
I quickly learned when I got my license 7 years back that cheap parts usually has poor fitment, lack of misc parts such as screws etc and a lower life span so I tend to buy from well known brands such as Bosch 😅
I’ll hopefully have time to shoot a video of me going to work, looking at the current and voltage tomorrow. Spare car is currently at work so I’m sorry to disapoint and drive my chassi there.
Supposedly I have start-stop in my vehicle, 7g plus etc if that has any impact on thia matter, however that has never worked during my ownership of ~2.5 years.
Crankshaft sensor as recommended by Arrie is a good idea. It would make sense with the failure and would cause the timming erros from your first post as well.
Crankshaft sensor as recommended by Arrie is a good idea. It would make sense with the failure and would cause the timming erros from your first post as well.
Crankshaft Position Sensor has yet again been exchanged for a brand new Bosch one, the car keeps on throwing the code of P034031 which the iCarSoft translates to
"Position sensor 1 for the intake camshaft(cylinder BANK 1) has an electrical fault. The signal is not present" - Code is current whilst car is running and historic when car is off.
The above makes me suspect that the wiring is the issue here or possibly the cars computer. Although I do not think this is related to the car shutting off as this code has been existing since I bought the vehicle and according to Autocom, for ~66 000 miles.
However! I received a new code when the vehicle shut off today which I haven't noticed before, went to current whilst trying to start the vehicle for a duration of time ~5 minutes.
U143364 - "An unreasonable signal 'state of circuit 15' was received. There is an unreasonable signal"
Thought I'd start of by chaning out more or less all the fuses in the car due to a lack of a better idea, although I realize that the signal shouldn't be affected by a fuse?
Any info on what Circuit 15 is would be greatly appreachiated, currently reading through another forum post which describes it. https://mbworld.org/forums/e-class-w...-87m-50-a.html
Oh!
I also changed the chain tensioner yesterday, did wonders for the startup sounds, wouldn't call it a rattle but it certainly was louder for a second, had naive hopes, didn't solve the issue but one less unpleasant sound
Edit 1: According to the thread of S-Prihadi this might be something? My issue is intermittent so not very likely but I'll certainly change out a few fuses tomorrow
Last edited by RaZtar; Nov 10, 2024 at 04:48 PM.
Reason: More info, felt unnessecary to make a new post.
Crankshaft Position Sensor has yet again been exchanged for a brand new Bosch one, the car keeps on throwing the code of P034031 which the iCarSoft translates to
"Position sensor 1 for the intake camshaft(cylinder BANK 1) has an electrical fault. The signal is not present" - Code is current whilst car is running and historic when car is off.
The above makes me suspect that the wiring is the issue here or possibly the cars computer. Although I do not think this is related to the car shutting off as this code has been existing since I bought the vehicle and according to Autocom, for ~66 000 miles.
However! I received a new code when the vehicle shut off today which I haven't noticed before, went to current whilst trying to start the vehicle for a duration of time ~5 minutes.
U143364 - "An unreasonable signal 'state of circuit 15' was received. There is an unreasonable signal"
Thought I'd start of by chaning out more or less all the fuses in the car due to a lack of a better idea, although I realize that the signal shouldn't be affected by a fuse?
Any info on what Circuit 15 is would be greatly appreachiated, currently reading through another forum post which describes it. https://mbworld.org/forums/e-class-w...-87m-50-a.html
Thanks
Swap both camshaft sensors between the banks to see if problem follows the sensors.
Swap both camshaft sensors between the banks to see if problem follows the sensors.
Hi Arrie,
Thank you for taking the time out of your day to try help me out.
I may be mistaken here but I thought there only was one camshaft sensor on the OM651, are you sure that you’re not confusing my engine with a V-Engine?
I,ve ordered relays for the J relay and N relay if I recall correctly for the Front Sam Box in the hopes of it resolving my issue.
"Position sensor 1 for the intake camshaft(cylinder BANK 1) has an electrical fault. The signal is not present" If this Fault code is still present, you can try start the engine with this sensor disconnected.
If engine starts and runs the same, than this Fault Code is real and you have to find the "electrical fault', meaning wires and connectors if the sensor is new and suitable for your car.
Hi Arrie,
Thank you for taking the time out of your day to try help me out.
I may be mistaken here but I thought there only was one camshaft sensor on the OM651, are you sure that you’re not confusing my engine with a V-Engine?
I,ve ordered relays for the J relay and N relay if I recall correctly for the Front Sam Box in the hopes of it resolving my issue.
Thanks once again
RaZtar from Sweden
Yes, thought it is a v6 engine. Did not see clearly anywhere the engine detail and then the error code talks about Bank one like there was another bank. If only one bank no need to mention bank number.
But, does it not have cam sensors for both intake and exhaust shafts?
If not then replace the one sensor you have unless you did already.
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