Ng 2.3 cut out?

**fourringsrus** · 10-09-2012,06:34 PM

We recently acquired a '90/'91 2.3 e NG Audi coupe, manual, front drive and with the intention of enjoying a bit of tinkering decided to make a bit of a mini project.After various points were addressed, ie, leaking door rubbers, smashed headlights, soaking wet interior carpet underlay etc,etc, we were fiddling about when the engine just stopped as if the key was switched off.
We now have no spark and no fuel pump getting power.
We checked out the fuel pump relay by opening it up and physically making the contacts meet and hey presto the pump primes up.
On advice given we ordered up a tested replacement ignition control unit as found behind the nearside ankle kick panel, fitted and tried again to no avail.

I am of the opinion that something tells the spark to spark and the pump to pump and whatever this is, aint not doin' it.

We have a good new battery, good new fuel in the tank,new fuel filter fitted and new ignition switch and barrel fitted, all fuses checked ( unless we missed one somewhere )

Am I missing something obvious here, we have had a lot of advice, ie , have you got petrol in it, have you changed the spark plugs, dizzy cap etc, etc, but nobody seems to be listening to the fact that we have two issues, spark AND fuel, there must be a connection common to both sides of the system.
What am I missing

Many thanks

Stuart

**scotty33** · 10-09-2012,08:16 PM

Stuart, you should be able to pull fault codes on this, the tricky bit is the ECU fault memory is volatile, so erases when the ignition is switched off, system is the same as this audi 100 link (the late 1989 type) :

http://www.sjmautotechnik.com/troubl...g/100ecuf.html

I know other Audi inj systems kill the fuel if there is no spark or vice versa? Would not be surprised if your faults are from the one cause

**fourringsrus** · 10-09-2012,09:07 PM

Cheers scotty,

Thanks for that link, has hopefully shed a bit more light.

Would you agree with my interpretation of picture 2, if I said that the power comes from the battery ... Goes to the fuel pump relay ... then is sent to 1. The ignition control unit .. then 2. Injection control unit ?

If so, could the whole problem be a knackered relay ? As it would make sense as to why we found a spare/old 215 (fuel pump) relay in the glove box after we got the car.

Many Thanks

Stuart

**scotty33** · 10-09-2012,10:01 PM

Back in the day I had a Kjet 4 cyl 80, my bro had a K jet 5 cyl, both cars killed their fuel pump relays, so would not be at all surprised. As a test you can just bridge the 2 big terminals in the fp relay socket, this should turn the fuel pump on whilst the 'bridge' is in place.

One of the functions of the fuel pump relay is the engines rev limiter, there is also a facility where if you crash the car and sever fuel lines, the engine will cut out, the fpr has an function, to cut fuel. Having said that, if you forced the contacts closed, I guess that is the same as bridging the socket?

I would go for fault codes, the tester is easy enough to make with a led, but a 1.2 watt bulb does away with polarity issues and the need for a resistor..

**fourringsrus** · 11-09-2012,09:29 PM

After chatting to Audi this afternoon, a seasoned tech man gives this impression that the fuel pump relay does in fact send to the fuel and the spark and is more than slightly possibly, what our problem is, so we will order a new unit at approx £24 and go from there.
Thanks for the link above and the advice thus far, watch this space and feel free to add anything that you may feel relevant.

Stuart

**fourringsrus** · 13-09-2012,06:37 PM

OK, the brand new genuine Audi fuel pump relay came today, from Audi and it made no difference, so back to the drawing board.
Inspected wiring from ignition switch forward but all appears to be sound.
Any more ideas?

Stuart

**scotty33** · 13-09-2012,07:57 PM

I would go for fault codes, you could test things like hall sender, ignition control unit etc but these should show up on a code read if they are the cause of the no start?

**fourringsrus** · 13-09-2012,08:54 PM

Cheers Scotty, I think I have read somewhere that this model can not be read by vagcom/vcds and that I need to read blink codes which means absolutely zero to me.
Do you think I need the professionals in or is this still within my abilities?

Stuart

**Crasher** · 13-09-2012,11:28 PM

When working on one of these, if VAG-COM will not communicate I use my old Omitec machine which will work on these. Without a diagnostic system and the differential pressure regulator break out wiring plus DMM and 4 gas you are stuffed trying to get an NG to run correctly. I still have (somewhere) the factory manual for setting these up. The KE-Motronic system is a bitch to set up, unless you know exactly what you are doing it is near impossible to set up a perfect one, never mind fault find one with a problem.