Engine Power Failure

[Gregg 147]

I've an Audi A2 1.4 TDI (diesel, 2002 plate). The car is experiencing problems once you're at 70 mph for a sustained period such as on the motorway. The car will suddenly lose power and the revs go up. The engine doesn't cut out and maintains the speed you are going but if you slow down, the car will not pick up again.
The car seems to go into 'safe mode' and has no additional power. This problem only seems to occur when going 70 mph etc. There are never any problems when travelling on the road. Once the problem does occur, if you turn off the engine, it resets itself and the problem is sorted, until it happens again. The car has just been in for service, it did show a fault in the memory but this disappeared after a road test and the technician has no idea. He checked the turbo overboosting but this showed ok. He replaced the solenoid boost and retested. The problem seemed to be ok. I've since tried it and the problem has not been fixed, yet still paying 565 quid for service ad engine managment investigation. He also seems to think it could be the turbo, but the car has only done 30,000 and is driven carfefully. Any ideas, suggestions or help would be greatly appreciated.

 

[GJR]

It could be the MAF sensor, or possibly the rubber hoses linking the turbo - if they are starting to perish, they flex more than they should and can, in some circumstances, close up altogether when boost is required. I'm not sure how this equates to the A2 diesel, but they're common problems with VAG 1.9 TDi units. I'd check the MAF sensor first, though.

 

[spike]

Hi Gregg
Welcome to the A2oc
There are a few previous posts relating to similar sounding problems but nothing conclusive regarding a fix :-
http://www.a2oc.net/forum/showthread.php?t=2302&highlight=power+loss

I concur with your safe mode theory as it does sound like a faulty sensor giving an occasional out of range signal which derates the power. Let us know if you solve the problem.

Cheers Spike

 

[spike]

Just read an old article in Audi Driver magazine (Diesel View in July 03 edition) which supports GJR's suggestion of the MAF sensor. Symptoms are the sudden loss of power lasting anything from a few minutes to a day or two, followed by a magical recovery and no faults recorded in the memory. Not sure if this is possible on the A2 but a suggested check is to remove the air intake ducting to allow visual inspection of the MAF hot wire. It should be glowing when the engine is running. It's faulty if it is not glowing (IF you do this, make sure there is nothing around (rags, etc) to get sucked into the engine when you fire it up!!!)

Cheers Spike