MartinH

1996 2.8L 140,000 miles. Normally it starts instantly and runs well, but several times over the last few months the engine has failed to start. Starter spins over fast, but engine fails to fire. After trying to start it for about 5 - 10 miniutes, it then starts and runs misfire free as if nothing had happened. Fault codes P1340 & 1392 (Manufacturers control ignition system or misfire) are displayed after the event. The fact that it normally instantly bursts into life and only occasionally gives problems makes me think plugs, leads and coils are ok! I have run 2 cans of dry gas through it but it just failed again. Can anyone suggest what may be the problem. It's my daughter's college car and I want to try to fix the problem before she gets stranded somewhere far from home! Help please!

4Driver4

Change the coolant temp sensor.

77'911

I would go through the usual cast of suspects. Its also worth hooking a VAG-Com up to the car to get the manufacturer specific DTC's. At that mileage I would also replace the ignition switch(about $15) if its not been done in its past history. Stop using dry gas, it just carbons things up.
1)check battery base voltage and through a draw test, cell test(if possible).
2)Check fuel running and rest pressures.
*when was the last fuel filter done?
3)check condition of fuel injector seals(upper and lower)
4)ohm out coils to see if they meet factory spec
5)ohm out the wires, I generally replace them every 60K.
6)Plugs, replace at least every 30k. These cars tend to run on the rich side.
7)check for crank case or vaccuum leaks
8)temp sensor(fan & head)
Not knowing the service history, its hard to guess over the web an issue as broad as the one you have.
Regards

chris w/ a b5 1.8t

cts seems to screw with alot of things.. surprising. (to me at least)

MartinH

Seems like it is overdue on the wires! Plugs are still within 30k. Fuel filter about the same. As a matter of reliability, I think the coolant sensor and the wires are the first things to replace as they are original! The head temp sensor - is that the one under the inlet manifold at the back? If so, that's a pain!

MartinH

CTS - Is that the one in the bottom left of the rad?

pac1085

MAF/MAP
Engine coolant temp
manifold air temp
rpm (from the vr sensor)

If any of those things fail to work right, it can cause weird issues

77'911

Not a problem. Being that the motor your dealing with is a 12v, I would add a few items to the list. The ECT(G62) sensor is located behind the passenger side head on the engine.
Added list:
1)clean out the idle control valve
*measured value to spec is 7-11 ohms
2)check EGR sensor(G98)-located under the thottle body.
Regards

4Driver4

No. In the coolant pipe at the rear of bank one.

MartinH

I just located a website
http://www.obd-codes.com/trouble_codes/audi/
that listed the following for the codes I have:

P1340 Crankshaft-/Camshaft Pos.Sens.Signals Out of Sequence

P1392 Camshaft Pos.Sensor,Bank2 Open Circ./Short to B+