A8 Parts Forum - My motor, seriously screwed....

Really, really weird last night.....

Coming home from a friends house, only about 4 miles away and the hazard warning lights come on, and the interior light. Also, the doors unlock. This is classic 'crash signal' behaviour and is what the car is designed to do in an accident to attract attention and easy access out of the car.

but I was travelling in a straight line, not even 'hoofing it' as I had been for a few days.

So I pulled over as I couldnt really drive with the hazards on. They wont turn off, so took the center console panel off (easy without tools on a facelift) and disconnected the hazard warning switch.

Then the hazards went off as expected, and the engine died, which wasn't so good. Tried to restart, which it did, and then died, just like an immobiliser fault. Reconnected the hazard warning switch and the engine ran fine. Most odd. So, given it was only a few miles away and late (so quiet) decided to make it home with the hazards on....

Got home, turn off the engine, removed the hazard warning switch again (to stop the flashing!) and started unloading the boot etc.

After a few minutes I could hear 'noises'. After a few more minutes I could still hear something weird, weird enough to make me open the botton, to which I find (bearing in mind ignition off!) the electric water pump randomly running and various solenoids clicking randomly.....

What the chuff was going on here. Vagcom showed errors on the ABS Central convenience but the engine was fine, apparently..... So I gave up, disconnected the battery and went inside as it was dark and cold.

This morning after some thinking, I concluded it could only be the engine ECU, which some will know is located in the 'water tightish' plastic plenum chamber at the top left back of the engine bay (viewed from drivers seat). In here is the gearbox ECU (when automatic), ABS/ESP ECU and Engine ECU. The whole box has a lipped lid with rubber seals and lots of writing to encourage dumb people not to let water get in it, for fairly obvious reasons.

Anyway, opened her up and sure enough, some good signs of condensation in there. Took out the engine ECU and there was a few drops on the circuit board itself.

The great news here, is that I dried it all out, put it all back togethert and shes purring great now but it was an interesting find.

It was a combination of a few factors that ****ed it all up. I had a dodgy washer jet on the passenger side, where the pipe would come off and effectively squirt water over the plenum chamber. Now this alone, wouldnt normally cause an issue as its sealed tight enough, but unfortunately my car was LPG converted by a garage who chose to drill a neat, concealed, and yet fatal hole through the plenum chamber to get their wires into the chamber to connect where needed.

It seems the recent 'thaw' caused the frozen condensation to become water again, thus causing my problems.....

So, I guess the moral of the story is that the A8 is still a fantastic car, but unfortunately some people do modify them in a way that doesnt respect the design, and it causes problems later on....

All fixed now though, and loving it +++