Please help - infuriating intermittent prob on W210 320CDI

[mr1970]

Evening

I recently bought a 2001 W210 estate, 320CDI. Lovely car apart from one problem that's driving me nuts and is going to see it traded in if I can't fix it.

Basically, there are times when it just won't accelerate past around 2000rpm. It will, given enough motorway, happily keep going past that all the way to 90mph or more (and since it's an Elegance I find it a bit soft up there so it doesn't get pushed far beyond that) but there's no pull. Most of the time, of course, putting the foot on the floor results in a big surge which will safely take me past in most overtaking situations, but accelerating and wondering whether it's going to decide to play or whether I'm going to get stuck on the wrong side of the road accelerating as fast as a Routemaster is really wearing thin.

A number of points worth mentioning:

- once it's done this on any given trip, the acceleration won't come back again. Sometimes it does it after 10 minutes of my 70 minute commute, which is a pain, sometimes with only 10 minutes left which is manageable. And probably 30% of the time it doesn't do it at all
- I can actually get the surge back again if I get caught at lights, in which case turning the engine off for 15 seconds usually persuades it to behave again

As for what I've tried:

- it's been into the local auto electrician who couldn't work it out
- it's been into the local general mechanic, who cleaned out the EGR valve
- it's been to a transmission specialist (Mackie's in Glasgow) who couldn't find anything wrong but serviced the transmission including a fluid change
- it's been to an independent Mercedes specialist on the South side of Glasgow who spent most of a day (and a smoke test) trying to work it out. They did change the air filter, which was getting flagged as blocked, but the problem still came back

My own theory is the MAF sensor as it's odd that turning the car off can "reset" the problem, but neither the electrician nor the merc specialist thought the codes were right for that. Given that I'm losing patience with the car, is it worth just getting a new MAF from eBay to try? Are they difficult to fit?

Any help greatly appreciated...

 

[grober]

Sounds as if the car is going into limp home mode in response to some out of spec sensor [ engine or gearbox] reading to protect the engine. In theory this should be logged as a fault code on the ECU and the fault traceable??? If you suspect the MAF some folks suggest running the car with it disconnected and the car then uses a default map- won't run as well but if the fault goes away?? Other thing to do is to clean the MAF with a solvent spray such as this SERVISOL AERO KLENE 50 Electronic Cleaning Solvent : Maplin Electronics about £5 Disconnect the connection plug remove the sensor held in with a couple of torx screws and give it a good skoosh with solvent- caution the sensor element is delicate so don't stress it physically by holding the jet too close! replace and see if it improves things? may be only a temporary fix but again pinpoints the MAF as a the source of your problem.- you can then splash out on a new sensor or complete unit? Other thing that can give weird symptoms sometimes that comes to mind is a partially blocked DIESEL PARTICULATE FILTER OR OXIDATION CATALYST in the exhaust.
ps buy a pukka sensor or MAF from a reputable supplier NOT ebay =too many cheap chinese knock offs going about

pps Quite often in modern cars the gearbox ECU talks to the Engine ECU-- This fault could be gearbox related - altho I would have thought your gearbox specialist should have picked up on this.

ppps other causes are simply mysterious electrical spikes on the system usually traceable to a battery on its way out or a dodgy alternator regulator/brush pack.

 

[GordonTarling]

A good bet would be the MAF - I'm told that it doesn't always log a fault code.

 

[mr1970]

That's great, thanks, I'll give it a go and post back if I get anywhere.

Cheers

Alistair

 

[ShinyF1]

I had a similar problem on mine but holding revs back to 3000rpm - MAF sensor cured it in an instant

 

[paultredgett]

try the gearbox sensor?

 

[Dieselman]

EGR or inlet flap motor, would be my guess.

What codes do you have?

 

[mick wakelin]

Chaps. I have just joined this site and this is my 1st posting. I have exactly the same problem, I have taken it to a Merc specialist who has read the codes and I'm getting:-
P2200, P1470, P0100 & P1222. I have yet to look these up, I have changed the MAF, the Merc man has supposedly checked the EGR valve, I have made and fitted the EGR shunt, now the possibility is that it is the DPF blocked.. I can't afford a new one, has anyone any experience of the ECU remapping and DPF removal. The car is in great condition, done 120K and was a pleasure to drive but now it seem OK for a while when I get that little phst sound as I take my foot off the accelerator and then after a while especially whilst going up a gradient I'm getting the phst sound every few seconds and the car loses power and it struggles to get to 80 MPH. any help would be SO greatly received.
Many thanks.
Mick

 

[mick wakelin]

BTW
It is a W210 Estate E320cdi 2001 (facelift) model 961
Mick

 

[Dieselman]

BTW
It is a W210 Estate E320cdi 2001 (facelift) model 961
Mick

No DPF then.

 

[mersum1es]

BTW
It is a W210 Estate E320cdi 2001 (facelift) model 961
Mick

Like above, no DPF. What you mean by EGR shunt? Have you just blocked it or followed by deactivation instruction here/there? Why your specialist didn't explain what those codes are?

 

[mick wakelin]

My independent Merc man did it as a favour, he connected up his diag tool and left me to read the codes.. he did not charge me for this.. However if he is now telling me it is a DPF fault and there is no DPF on this car I'm not sure how much of a favour it was. The codes were as follows:-

P2200 Component Y3/6n2(speed sensor 2) is faulty or the sensor supply has Short circuit.
P2200 Instrument cluster Fault from instrument cluster over CAN
P2200 Instrument cluster Preglow indicator lamp faulty
P1470 Charge pressure control On/off ration of actuation is too large.
P1470 Charge pressure control Open circuit
P1470 Charge pressure control Positive control variation [Charge pressure is too high.]
P1470 Charge pressure control Positive control variation [Charge pressure is too low.]
P1470 Charge pressure control Short circuit
P1470 intake air pressure regulation
P1470 Intake pressure or boost pressure control
P0100 Mass or Volume Air Flow Circuit Malfunction
P1222 accelerator pedal position sensor B37
P1222 B37 (Pedal value sensor) Sensor 1 Plausibility 1
P1222 B37 (Pedal value sensor) Sensor 1 Plausibility 2
P1222 B37 (Pedal value sensor) Sensor 1 Plausibility 3
p1222 B37 (Pedal value sensor) Sensor 1 The signal voltage is too high.
p1222 B37 (Pedal value sensor) Sensor 1 The signal voltage is too low.
p1222 B37 (Pedal value sensor) Sensor 1 The supply voltage is too high or too low.
P1222 Potentiometer R25/2
I recently had the cluster out to fix the clock and temp display so I guess that rules out P2200
I have changed the MAF so I guess P0100 can go.. I have no idea what the others mean.. I fitted the EGR shunt 2 resistors and a diode, I'm not sure I needed to, I had no smoke and it has made no difference..

I have a Triumph Stag which has probably one of the most unreliable engines ever made but I can fix it / rebuild it etc and have done... Mercedes on the other hand... I have NO idea or experience on diesel engines, can anyone recommend a good independent Mercedes or diesel specialist that knows what they are doing, won't rip me off and can fix my problem.. preferably in Surrey.
Mick

 

[mersum1es]

According the codes turbo actuator and pedal position sensor are misbehaving/gone. Should not be very expensive. (edit: here similar turbo issue in other forum http://forums.mercedesclub.org.uk/showthread.php?t=110686)

The EGR fix could be ok (I think it definitely need those components, otherwise limp mode is certain), can be tested when other things are ok.

 

[mick wakelin]

FIXED
UPDATE.. I took the car to nick georges garage in Surrey.. (UK) picked it up engaged warp 9 and wow... it was all back... the car flew.. no errors.. no limp home, more leap home. £150 INCLUDING a courtesy car for a day.. Real old school garage that really care... talk to their tech wizzard Colin..He does mercedes magic..
Special thanks to Mersum1es..

 

[mick wakelin]

For those that are curious.. he checked the cat was not blocked, checked all turbo / vacuum pipes / hoses, checked turbo actuator, cleared the errors but got the throttle position sensor error back. car drives fine but now I know what to get fixed if and when it happens again..

 

[design guru]

I have an issue in my S320cdi, I replaced the MAF sensor even though it was 5 months old and it made no difference, turned out the housing on my turbo had broken and was no staying in place and the turbo was running but not directing the power correctly.

I am looking to replace the turbo soon as it currently only gives 50% power.