160 Holland Ave.

Thank for the information silverd2. When the car dies out on me while driving and i go to restart it i dont hear the fuel pump kick on at all. Maybe its a short somewhere ? I'll keep looking and keep you posted. This thing is driving me nutts.

BrianC72gt

That is the question. Pull the codes, CLEAR them and then see if any new ones show up. Old codes aren't always cause for alarm. New ones are worth looking at. If you get lots of crazy seemingly unrelated codes, check under the hood, passenger's side for any standing water in the cowl area causing the PCM (audi-speak for the ECU) to get wet and freak out.

Does it die and throw codes or does it die and throw no codes? I could throw a lot of guesses out...ignition switch, cheap *** replacement coils, fuel pump relay, combination relay, flywheel sensor, etc... but first Clear all the old codes and see if it throws any new ones when it dies. That fork in the road will help a lot.

160 Holland Ave.

Will do i just ordered a vag com cable. I did clear all the codes with my friend scan tool. I keep you posted. This thing is a nightmare !

160 Holland Ave.

Yes there is water under the ecu box but i never had this problem before. I've owned it for 4 years now. I dried the water up and checked the box it self and everything looks dry inside. It dies and throws no codes.

BrianC72gt

When it dies, does the check engine light come on like it is supposed to? The CEL should be on anytime the key is in the RUN position but the engine is not on. If not, I'd check the ignition switch; the ECM Power Supply Relay in the relay box UNDER the passenger's front carpet pad, in the mdf box...3 screws; or the fuel pump relay (same location).

Basically, you are looking for a failure that will cause the engine to die, BUT won't record an error code. Things like a bad coil or coils WILL throw a code. The ECU loosing power or the fuel pump cutting out won't. Likewise for corrosion on the connections on the framerail in the passenger's side footwell. Or a bad ECU. Hopefully the intermittent failure will become a permanent one, making it much easier to find.

Look at pages 13 - 16 in this wiring diagram:

http://www.mitchell-auto.ru/UserFile...audi-s8-wd.pdf

Wires that exit to the right of a page enter the wiring diagram on the left of the next page. The ground locations are down on page 22.

160 Holland Ave.

No check engine light when it cuts off. These are what i got from the scan.

Secondary air pump solenoid valve- short to ground
egr valve - short to ground
engine speed sensor - no signal
multiple mis fire
and my gas needle just started to bounce around.
but no engine light on.

160 Holland Ave.

So I cleared the codes and drove the car for like an hour till it shut down on me at a stop sign. Ran vag-com and engine speed sensor came up no signal. I just put the speed sensor in back in October. I will order a new and install it and we'll see what happens. I'll keep you guys posted hopefully thats what it is. Fingers crossed.

silverd2

I believe you may have found your problem. Any time the engine speed sensor loses signal, the ECU will cut electrical ground to the fuel pump relay...fuel pump off...intermittent signal = pump on and off = misfires and stalling.

You can break (or ground signal) the speed sensor if you over-torque it on install.

160 Holland Ave.

Here an UPDATE. Took out old engine speed sensor (g28) the wire was burned because it was hitting the manifold. Ordered a new sensor installed it yesterday afternoon. Cleared the codes and drove it all day put on about 50 miles and all is well. Didn't shut off on me while driving. Hopefully no more problems. Feels good driving it haven't driven it for a year now. WHAT A RELIEF !

Thank you all for all the help and support. I really appreciate it.