1996 C4 2.6 .. Wierd electrical & engine behaviour??

Yerfdog101 · 10-22-2007, 09:14 AM

Hi,

I hope you can help me, my A6 has started exhibiting some unusual traits. On a cold morning I will start the car & the engine will shoot up to 3000rpm , then as soon as the revs drop to 1600 it boost back up again to say 2k. The engine continues in this way until it is switched off.... which gives for a bumpy ride!!. The when you fire it back up on a warm engine... it is fine.

Also on the odd occasion when starting the car the electric sunroof has decided to slide fully back without any provocation. I have then needed to wind it back by overriding the motor to get it to reset!....

I am wondering is maybe some damp is getting into the ECU electrics or could a dodge battery cause these issues???

HellBent · 01-22-2008, 10:45 AM

It sounds like a battery issue... My sunroof goes open when the battery gets completely dead, and when it gets recharged. This could also be whats causing your fuel pump not to pump or your spark plugs not to spark, ect. It could be your alternater also.

dfh44 · 01-22-2008, 12:11 PM

Hi Just had the same problems on my A6
New battery was fitted, but erattic idle control still happened. Remover idle control valve, mounted on side of intake manifold by 2 5mm cap head bolts. Just cleaned it with brake cleaner and compressed air to blow out the debris and refitted and HEY idel control again, both hot and cold conditions.
Have had funny events with sunroof though, but will wait a while now new battery is fitted.
Hope this helps..
PS Do not try and start the engine with this unit disconnected, Best to complete all the work with the battery disconnected.

Yerfdog101 · 01-23-2008, 04:14 AM

Thanks Guys,

I changed the battery & that seemed to solve the problem ... for a while. The engine is performing Ok now, no further bouncing the revs up to 2000 etc. However I do still have the electrical faults within the cabin. For example...Sat in traffic waiting for the lights to change & the sunroof 1/2 opens (tilt) ... I managed to close it but cannot now reopen it properly unless using the manual overide etc.

At the end of a journey I stopped the car turned off the engine and the central locking locked me in the car!!

I am concerned that there may be a fault in my ECU? What do you think?

10-22-2007, 09:14 AM	#1 (permalink)
Yerfdog101 Newbie Join Date: Sep 2007 Posts: 6 Gallery: (0)	1996 C4 2.6 .. Wierd electrical & engine behaviour?? Hi, I hope you can help me, my A6 has started exhibiting some unusual traits. On a cold morning I will start the car & the engine will shoot up to 3000rpm , then as soon as the revs drop to 1600 it boost back up again to say 2k. The engine continues in this way until it is switched off.... which gives for a bumpy ride!!. The when you fire it back up on a warm engine... it is fine. Also on the odd occasion when starting the car the electric sunroof has decided to slide fully back without any provocation. I have then needed to wind it back by overriding the motor to get it to reset!.... I am wondering is maybe some damp is getting into the ECU electrics or could a dodge battery cause these issues???

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01-22-2008, 10:45 AM	#2 (permalink)
HellBent Member Join Date: Feb 2006 Posts: 52 Gallery: (0)	It sounds like a battery issue... My sunroof goes open when the battery gets completely dead, and when it gets recharged. This could also be whats causing your fuel pump not to pump or your spark plugs not to spark, ect. It could be your alternater also.

01-22-2008, 12:11 PM	#3 (permalink)
dfh44 Newbie Join Date: Jan 2008 Posts: 2 Gallery: (0)	Hi Just had the same problems on my A6 New battery was fitted, but erattic idle control still happened. Remover idle control valve, mounted on side of intake manifold by 2 5mm cap head bolts. Just cleaned it with brake cleaner and compressed air to blow out the debris and refitted and HEY idel control again, both hot and cold conditions. Have had funny events with sunroof though, but will wait a while now new battery is fitted. Hope this helps.. PS Do not try and start the engine with this unit disconnected, Best to complete all the work with the battery disconnected.

01-23-2008, 04:14 AM	#4 (permalink)
Yerfdog101 Newbie Join Date: Sep 2007 Posts: 6 Gallery: (0)	Thanks Guys, I changed the battery & that seemed to solve the problem ... for a while. The engine is performing Ok now, no further bouncing the revs up to 2000 etc. However I do still have the electrical faults within the cabin. For example...Sat in traffic waiting for the lights to change & the sunroof 1/2 opens (tilt) ... I managed to close it but cannot now reopen it properly unless using the manual overide etc. At the end of a journey I stopped the car turned off the engine and the central locking locked me in the car!! I am concerned that there may be a fault in my ECU? What do you think?

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