The A8 Wont start / Gearbox electronics Investigation

[Dezzy]

Is it the main one under the car? I had trouble with this connection in 2010

Originally Posted by Dezzy

Ok so i won't go into details as i wouldn't want to bore anyone. But the 8 won't fit on the trailer as it's too wide and no i didn't check first as we've had a tractor on it before i made an assumption so i couldn't use the ramp.
But it turns out to be one of the lug connectors in under the big area of green powder on the OSF. Clean up and replace connector and i will be away again.

I didn't get a photo but it's down by the wheel arch, and should have a cover fitted although mine was so powdery it had forced the cover off.

[IT]

Yes, its pesky alright. Mounted underneath the drivers side chassis box section inside a black plastic box, bout 2/3 inches long.

The starter and alternator connect into it, and it then runs the length of the car back to the battery.

A completely separate, unjoined +ve feed runs from the passenger footwell electrics box back to the battery which is why the problem never affects anything else, unless of course through lack of charge the battery expires

I had it on one of my D2's. Drove me potty for a while. Its well worth opening it up, cleaning it all out, greasing it up nicely and resecuring....

You'd think there would be a tell tale sign of the starter struggling, or slowing, but its surprisingly on / off - Something to do with the current required for the starter being there, or not. And if it isn't, just no solenoid action and its all dead....

Thanks for sharing a detailed and informative first post

[47p2]

Anyone know where the earthing point on the D3 is?

[Delboy]

Driver side chassis rail, arch liners out to see it

[47p2]

Thanks, will have a look

[47p2]

Just had a look and the D3 earthing point is indeed under the liner of the front driver side wheel arch behind the strut, thanks Del It's possible to access the bolt without removing the liner if you can get the use of a ramp Not sure if Audi had the earth cable off when doing the repairs but the bolt was not as tight as it should have been, I gave it about a 3/4 turn to nip it up


Interesting what you see when looking for something else

Plastic trim hanging off, so a trip back to the Audi body shop tomorrow to kick up a stink. One of these push in plastic clips with the centre pins has not been replaced



Also the carpet liner has a plastic nut missing, it's in an awkward place so they probably found it easier to leave it off



I've removed the plastic part as I don't want it to fall off onto the road



Just to update this and not divert away too much from the original thread. Took the car in this morning and they put it on the ramp and replaced the missing parts. The guy who worked on the car can't remember taking these parts off, but as nobody else has been in there I doubt they have just loosened and came of on there own. Also booked it in tomorrow to have the scratch they inflicted on the mirror cover repainted

[johnny_quattro]

Originally Posted by HPsauce

Great info. Where is the bolt?

I think it may be shown in one of the two photos that I took when my old barge was having its gearbox done last year. The clearer photo of the back of the engine (nearside on the left of the photo, offside on the right as you look at it) also shows quite nicely two of the big fat drains either side of the flywheel/gearbox housing. I gave them a good squeeze at the time, due to the lack of access when it was all put back together.

There is a big old earthing strap which is brown in colour coming from somewhere on the engine/gearbox housing which leads to this black plastic box on the chassis rail - you can just about see it on the far right hand side of this photo. The other photo which is slightly out of focus (apologies for that) shows the back face of the OSF wheel and chassis rail power block/box.

I hope that this information is of some help. Please feel free to correct me if I'm wrong in any of my assumptions.

[johnny_quattro]

Originally Posted by ChrisG

Physically you could hear a metallic click which meant it was trying to do something, but then wouldn’t.
This problem seemed to be electrical.

That was exactly my experience a couple of years ago. It resulted in me getting the Audi placed on a lowloader and taken back home. A new starter motor was fitted to no avail, and I'd replaced the battery with a Bosch Silver jobby. It turned out to be a similar fault to your problem and was discovered by the garage after a bit of troubleshooting. The connections inside the box were all gunked up, so they were cleaned up and put back. Everything worked perfectly. The garage let me have the new starter motor for free as it was too much trouble to take it all out again - result!