Question for Tame Technician

[Phil R M xk150]

Hi Tame Technician or anyone who recognizes this problem,just wondered if you could help me with a problem I have with my 2010 Audi A4 avant 2.0 tdi.
This problem occurred about 2 weeks ago and has progressively got worse. Car starts fine and tickover is fine, after being driven for about half mile the engine just dies, (as if ignition has been turned off). If I ease off the accelerator it picks up again and drives fine for a short time, then it happens again. If I don't ease off the accelerator it doesent pick up, only when i ease off does it pick up again. The engine does not cut out when it dies, if i take my foot off the accelerator and press the clutch in the engine tick's over fine. No engine warning lights on....Just wondered if you had any ideas.... Cheers Phil.

Edited by Phil R M xk150 on Sunday 18th January 11:29

Edited by Phil R M xk150 on Sunday 18th January 11:44

[Dr G]

Dumb question: mileage and when fuel filter was last changed?

[Phil R M xk150]

Hi Dr G. I've had the car for about 10 months, the only other owner was Audi. It,s done 120.000 miles. Its been well looked after and maintained by Audi. The fuel filter was changed at 112.000 miles.When it runs, it runs and tick-over smoothly. Doesn't cough and splutter.
Cheers Phil.

Edited by Phil R M xk150 on Sunday 18th January 14:23

[morgrp]

Whats the throttle body looking like? They are known to "gum" up and get stuck - a diesel throttle works in the reverse of a petrol engine controlling the air flow e.g opens and close rather than the other way round. I can gurantee Audi won't have even looked at it and it will be as black as a coal miner's underwear in January. - Easy to remove and clean yourself with some Super TT spray (or WD40)and a bit of scotchbright.

[Phil R M xk150]

Thanks for the reply morqrp.
I wouldnt know where to start looking for that, as you will notice from my user name I'm an old Jaguar man. Ive booked it in at the local Audi garage on Tuesday, just looking for a heads up on what may be the problem before I get there.Being an Audi I'll bet It's expensive.

Cheers Phil.

[Phil R M xk150]

Just got back from the garage, no faults show on computer, it drove fine for the 7 miles there, but happened several times on the way back.Just going to take it for a long run then take it back there,any ideas!!!.
Cheers Phil.

[morgrp]

https://www.youtube.com/watch?v=RwQ1q-EcG58

[bigvanfan]

Phil R M xk150 said:

Just got back from the garage, no faults show on computer, it drove fine for the 7 miles there, but happened several times on the way back.Just going to take it for a long run then take it back there,any ideas!!!.
Cheers Phil.

Someone has given you advice on what to check, I'd assume they know about these engines so maybe worth checking it before asking for more ideas?

[Tame Technician]

The throttle body is wide open all the time on a diesel engine, It only closes when you key the engine off, it might close a little for DPF regen depending on the engine.

The engine in the youtube clip is a PD the OP has a CR. The manifold flap is a completely different item not shown in the vid.


That said the fault could be the flap in the throttle body mechanically broken (or the gears that drive it worn away) so the flap moves on its own to a near closed position slowing the engine.


If I was a betting man I would say its an EGR valve fault, the new type of EGR valve on the CR engines can give sporadic performance issues, unlike the old one you cant just clean them out.


But there are a number of other things, DPF sensor, exhaust gas temp sensors, fuel pressure and so on that could give the same symptoms.


If it wont log a fault code, you need a good techncian to drive the car while the fault occurs monitioring the live data from the engine to figure out what is going wrong. If it happens enough it should log a code to point them in the right direction.