W211 Cdi

[GEH007]

No, not yet, but plan to, hopefully this week. Is that now the most likely thing in your opinion?

 

[bobmedley]

I had the E320 CDi and I'm sure it had an electronic throttle - the pedal was linked to a potentiometer(?) under the bonnet. This may be the problem, but I don't know whether a squirt of WD40 or whatever may fix it. It might be cheaper than an Air Mass Sensor though.

 

[BlackC55]

No, not yet, but plan to, hopefully this week. Is that now the most likely thing in your opinion?

There are a few on the list but you must start at the basics and work upwards..

 

[BTB 500]

FWIW our Audi A4 (1.9 TDi auto) does this too. It's barely noticeable, and the car starts and runs perfectly otherwise so I've not bothered to do anything about it so far.

 

[jaymanek]

this sounds like the water getting into the oil issue that is common on the W211, i think it causes the torque convertor to slip, it was a recall IIRC...

 

[lexon]

I have the exacts same issue with my w211 e320cdi. Initially i thought it was the engine but now I'm suspecting something else. if I hold the accelerator pedal at a constant pressure the oscillations increase to such an extent the car feels similar to driving over cobble stones. It isn't a whell balance issue as it is rev induced rather than speed..

 

[BlackC55]

I have the exacts same issue with my w211 e320cdi. Initially i thought it was the engine but now I'm suspecting something else. if I hold the accelerator pedal at a constant pressure the oscillations increase to such an extent the car feels similar to driving over cobble stones. It isn't a whell balance issue as it is rev induced rather than speed..

There is probably coolant in your atf.

Its an expensive repar so be aware.

 

[timskemp]

An update:

Thought id try something today and was interesting.

Same 40mph speed, but used the speedtronic crusie control and guess what? It doesn't happen.

So, I presume that rules out dirty injectors?

What about MAF or auto box? seems odd I know.

Have you recalibrated the pedal module thingy? IIRC it's something like ignition on, press accellerator to kickdown, wait then release slowly but I'm sure someone will be along in a minute with the correct procedure!

 

[BlackC55]

Have you recalibrated the pedal module thingy? IIRC it's something like ignition on, press accellerator to kickdown, wait then release slowly but I'm sure someone will be along in a minute with the correct procedure!

That doesn't work.

I have proved it with my Star.

It is supposed to re-set the adaption data in the 'box.

 

[timskemp]

I have a feeling all it does is recalibrate the accellerator position sensor by moving it through the entire range - anyone who's owned a recent Volvo with an ETM (raises hand) will know that the buggers change with use - Volvo's little marelli unit actually wears through the carbon track on the pot. People who drive gently have more problems (or spend a lot of time idling or at a fixed speed) as it wears quicker.

 

[se97mlm]

That doesn't work.

I have proved it with my Star.

It is supposed to re-set the adaption data in the 'box.

As far as i know, it doesn´t modify the autobox adaptation, but the linearisation of the throttle pedal. For example, if you drive lazily with light throttle, the ECU makes the pedal more and more unresponsive: you have to push much further to get the same output. If you cane around a bit, the ECU uses a sharper response curve for the pedal so less movement gives more effect. If one stays in "lazy mode" too long, it takes ages to get the responsive mode back, and hence the reset can bring something.

Essentially it´s like how the Sprintbooster works

Regards

Matt

 

[BlackC55]

As far as i know, it doesn´t modify the autobox adaptation, but the linearisation of the throttle pedal. For example, if you drive lazily with light throttle, the ECU makes the pedal more and more unresponsive: you have to push much further to get the same output. If you cane around a bit, the ECU uses a sharper response curve for the pedal so less movement gives more effect. If one stays in "lazy mode" too long, it takes ages to get the responsive mode back, and hence the reset can bring something.

Essentially it´s like how the Sprintbooster works

Regards

Matt

I will have to prove that too.

I think I can.