2.2 Dti shudder and smoke problem

[signum_jon]

I've had a lot of help and advice from everyone on here and can probably be a little more specific about my problem now - symptoms as follows:

Car tries to stall when pulling away, shudders (like a bad misfire) on the move but at between 1500-2000rpm (in any gear) and blows out a lot of black smoke as you accelerate out of this rev range. After 2000rpm there is no smoke and it pulls perfectly. Fuel consumption seems reasonable at approx 44mpg average.

I did have the spanner light coming on at higher revs but a new upper inlet manifold/throttle body has eliminated this part of the fault.

Now for the interesting bit..... if I disconnect the electrical plug from the egr valve and drive the car it automatically goes into restricted power mode and so has no go above 2000ish rpm, however........with the egr disconnected I do not get the attempted stall when pulling away, nor do I get any black smoke or shudder in the 1500-2000rpm range that was previously the problem.

So, in summary:

egr connected = trying to stall, shuddering, lots of black smoke up to 2000pm but fine after

egr disconnected = runs fine up to 2000rpm (no stalling, no shudder, no smoke), but ecu puts car into restricted power so can't access the higher rev ranges

Can I assume that the egr is shagged? Or is there something else that I should be looking at?

I'm halfway to getting this car running nicely so just need to solve the last part of the puzzle!

Thanks to everyone who has helped me get this far!

Jon

[roswell]

EGR sonds likely take it off and give it a clean, or ... give it a couple of taps with the handle ed of a screw driver while someone else revs the car ;-)

If you clean the car and that doesnt fix the problem have a look at crank shaft sensers these seem to fail once the engine is warmed upto temp and give the symptoms your discribing

[ptrehearn152]

as above, had similar prob with mine, replaced upper manifold and egr, also took the lower manifold off and gave that a good clean up as it was coked up, touch wood now runs perfect.

warning though egr for these mega bucks (for what they are).

[signum_jon]

as above, had similar prob with mine, replaced upper manifold and egr, also took the lower manifold off and gave that a good clean up as it was coked up, touch wood now runs perfect.

warning though egr for these mega bucks (for what they are).

I followed your advice on my previous thread and changed the upper inlet manifold/tps/boost sensor setup as my brothers gf works for vauxhall and managed to get the part for £195 for me. That has transformed the top end and cured part of the problem.

I'm going to bite the bullet, replace the egr and hope that sorts the bottom end problem now. With a bit of luck that will see the end of the spending for a while at least!

Cheers, Jon

[signum_jon]

Okay, have finally sorted my poor running problem with a bit of help from a local diesel specialist and their diagnostic gear.

The EGR was shown to be opening and closing just as it should do so didn't replace that after all, then we were looking at removing the whole of the inlet manifold and cleaning it up, but on closer inspection and a few test drives it was decided that this was unlikely to be the cause of the problem and the time involved in doing all that may not have proved profitable.

As the car was clearly overfuelling, a new mass air flow senser was put on, but that almost instantly threw up the spanner light and put the car into limp home mode. Although it's not the cheapest way to go, we ordered up a new Bosch sensor to double check and fitted that this morning.

Btw, at no point were we getting any codes to suggest the original MAF sensor was faulty.

Result???.......Car is driving perfectly now - no smoke, no flat spot, and no violent juddering down the road.

The moral of this story is that it pays to get the genuine part rather than an aftermarket replacement sometimes! Been chatting to dylan1875 who had similar symptoms and it turns out that a non genuine part has been the source of his problems too, so don't assume that the "new" bit is working as it should just because it's new.

Cheers everybody!

Jon