Continued intermittent starting issues

[gbleenz]

My ABY coupe has been having intermittent starting problems for quite a few months now. I posted back in June about this problem & I thought that it'd been fixed when the ignition switch was found to be faulty and was replaced. Turns out that it didn't fix the problem as I initially thought.

I've had my local Audi service centre looking at it & they have tried swapping out the fuel pump, however that didn't fix the issue either.

They now suspect that the ECU is at fault & isn't controlling the fuel pump relay correctly. Has anyone heard of this happening?

They said that the ECU reports the chassis number as being a series of Ys (YYYYYYYY...). Weird.

I'm taking it to another Audi service centre next week. Any tips that would save them time (and me money ) would be most appreciated.

[rynaqui]

Does the car run fine once you get it started or does it run rough?

[rynaqui]

Also, have you checked the condition of spark plugs, coil packs, isv, perhaps an old fuel filter?

Could it also be a faulty injector? Perhaps a bit clogged up? Maybe the system isn't pressurizing enough before startup? Does it ever start up properly without any problems?

[UrS4boy]

J17 Fuel Pump Relay info

The ECU controls the J17 fuel pump relay. The ECU needs a good G28 engine speed signal before it will trigger the fuel pump relay. The J17, in turn, powers a number of devices. The engine will not start until the ECU also has a good G40 cam sensor signal and a good G4 crank position sensor signal.

Here is a link to an UrS4/S6 J17 fuel pump relay AAN discussion that applies in general to the ABY (wire colours might be different). Follow the hyperlinks within the J17 discussion:

http://forums.quattroworld.com/s4s6/msgs/22583.phtml