170 TDI hesitation under partial throttle

[Rhodesy]

How doo

Our A4 has recently developed an issue where when driving at low revs the engine has a slight hesitation resulting in the car jerking. This most commonly happens in 3rd gear whilst crawling along in traffic.

Having searched around the site I am thinking to clean the egr valve but wondering if anyone has other suggestions on possible causes?

The car is a 56 plate S line Quattro with the engine code BRD and has covered 95k with an oil change performed at 92k. The air and fuel filter were changed at 83k and there is a receipt for the egr valve being replaced at 79k.

Any advice gratefully received!

 

[syko89]

I have the same issue. 2.0TDI S-line (170) with 96k miles. Interested to know what it might be. Was tempted to give the EGR a clean to see if that improved things.

 

[YSN]

I had a similiar problem but my one was just moving off the cars revs would bounce up and down. I cleaned the EGR and Intake and now it runs very nice and smooth I also sprayed all my electrical connections with a bit of WD-40 as my problem mainly occured when it would rain or be damp outside now the problem is gone. EGR clean or delete is well worth your time.

 

[Rhodesy]

Update - still not got round to doing the egr but on a recent trip up the M1 the car went in to limp mode. Switched off and back on and all was back to normal so finished the journey. Got a scan of the ecu a few days later and found the following fault code:

00065 - boost pressure regulation
P0299 - 006 - Control range not reached - Intermittent

The garage tested out a few things and put it down to either a faulty pressure sensor or sticky turbo vanes. We replaced the sensor and the car now feels so much smoother, pulls harder and no more hesitation either.

The garage we used is called Ultimate Car Care in Sheffield, actually a BMW specialist (shame I know) but they have been excellent on both this and a previous occasion so I highly recommend them.

Hope this might help someone in future although I still intend to give the egr a fettle when I get chance

 

[Rhodesy]

Well, after being fine since the pressure sensor was changed, today the A4 did the old limp mode thing again. Really thought we had it cracked but seems not, went to pull away and no boost then limp mode. After turning off and on again the limp mode went away but car was still very stilted on boost for a while with intermittent bursts of power. Got to a quiet bit of road so booted it to the redline in 3rd and this seemed to clear it - fine for the rest of the journey.

Anyone had sticking turbo vanes and did they give similar symptoms to the above?

 

[Chris6t9]

Well, after being fine since the pressure sensor was changed, today the A4 did the old limp mode thing again. Really thought we had it cracked but seems not, went to pull away and no boost then limp mode. After turning off and on again the limp mode went away but car was still very stilted on boost for a while with intermittent bursts of power. Got to a quiet bit of road so booted it to the redline in 3rd and this seemed to clear it - fine for the rest of the journey.

Anyone had sticking turbo vanes and did they give similar symptoms to the above?

My a3 170 quattro has the sticky vane problem. Mines been remapped tho. i get it in second gear under full load, and also get over-boost.
The over-boost was nowhere near as noticeable when it was at 170 tho.

It will be going in for a new turbo within the next few months!

 

[Rhodesy]

Cheers for that matey, think I will start saving for a new turbo now lol. Have read a few posts mentioning cleaning the turbo vanes - anyone know if there is a how-to and if it is recommended?

 

[hollows wife]

only way to go, to get rid of the overboost problem either that or a new turbo . get the turbo off the car after that the rest is easy