S211 E320 2007 Facelift - gearbox conundrum....

[Hotdatum]

Ok Fellas,

My beloved E320 is behaving strangely. Occasionally (twice in the last three weeks and once at Christmas) I'm losing kickdown mid journey. Car will only then accelerate very slowly and not much past 50mph. Switch off and switch on and bingo - normal service resumed.

She's always had a quirk where if you floor the accelerator sharply from a low speed she will "kangaroo" along - immediately lift the accelerator then slowly apply full power and she picks up fine.

No fault codes stored in the engine....

124k miles. 2007 assembly.

Any one got any thoughts or seen this before?


Transmission: 722902 01 444370


Engine

Engine no.: 642920 40 540392

 

[television]

This could well be the start of the MAF failing.

 

[whitenemesis]

Diagnosis via STAR first step.

Could be failing electroplate in the autobox, often resets on cycling IGN. Codes will be stored. If the 'plate it could go imminently, could go on for months..

 

[Hotdatum]

Thanks for the prompt response guys.

Hmmmm. She moves through the gears perfectly in manual when this is happening, but still won't accelerate hard (eg in second from a roundabout).

It's the kangarooing which has always puzzled me. I put it down to too much power after an ECU remap but could it be a bad MAF?

 

[television]

I still say the engine power is dropping off, this will confuse the gearbox and it does not know what to do, the gearbox has nothing to do with the power output from the engine.

 

[whitenemesis]

Thanks for the prompt response guys.

Hmmmm. She moves through the gears perfectly in manual when this is happening, but still won't accelerate hard (eg in second from a roundabout).

It's the kangarooing which has always puzzled me. I put it down to too much power after an ECU remap but could it be a bad MAF?

Which is why STAR diagnosis required, take out the guesswork...

 

[television]

On many engines you can pull the plug off the MAF and try the car, it may run much better, and it will do no harm to try it, there are very few things that correct themselves by turning engine off and on again.

 

[Hotdatum]

Does it need to be STAR it will any garage diagnostic machine be able to access the fault codes? Only ask as its a schlep to my nearest Indy....

 

[television]

Where are you in Somerset, another thing here is it could be the flaps sticking in the intake manifold, I am in Lyme Regis and I have STAR, but plenty of indies around.

 

[whitenemesis]

Generic ODBII readers are not too bad on engine codes, some better than others. Some will read TCM/ Transmission codes but never 100%. Few read MB chassis codes. Problem is the code ref returned doesnt always mean much with specific MB faults.

That said a good tech should be able to work it out but there really is no complete substitute for STAR and an tech experienced in using it.

 

[Hotdatum]

Thanks guys,

Malcolm - thanks for the STAR offer, I'm in Frome so a bit too far realistically, but I value the advice from both of you. I'll have to get it on a STAR near Portsmouth (I'm in the Navy and work there during the week)

Tom

 

[whitenemesis]

You have MBS just down the road, our very own Cole, member on this forum

http://forums.mercedesclub.org.uk/member.php?u=29766

Or Olly at PCS in Horndean

http://www.prestigecarservice.co.uk/contact

 

[Steve@Avantgarde]

This a V6 diesel. Dont disconnect the MAFs, it will put it in limp mode.

This will either be an exhaust back pressure sensor or a jamming turbo wastegate regulator or both. The kangerooing on throttle is a classic complaint for this type of fault.

As advised, you need to get it on STAR.

And Frome isnt too far from my place......for the next 11 days at least! Or you have John Wareham at Class Motor Services up the road in Binegar, an old colleague of moine from MB Bath, hes a good guy.

 

[Hotdatum]

Thanks again.

I'm now stranded at home looking after a toddler whose had an ear opereation. In the absense of a STAR we connected the car to friends laptop. Fault codes relating to the EGR were logged along with a couple of others.

We cleared all and it's since dropped back into limp mode. We will reconnect on Monday and see which new codes are logged.

Are you moving from Martok Steve?

Cheers all.

Tom

 

[Hotdatum]

Photo of the error codes attached.

Any thoughts?

 

[rpe2]

BAck pressure sensor looks suspect. About £50 from a dealer - easy to fit.

Others can advise re the EGR codes.

 

[Hotdatum]

Thanks Richard.