gatorade1987

Hey there, I'm a long time volkswagoner but newbie to Audi. I recently picked up an 84 quattro 4000s. the gentleman I bought it from claimed it had no spark and had sat in his garage for about 9 years. I got it home and determined the coil was indeed bad, replaced it (fixing the no-spark issue) but still couldn't get it to start. I realized that the fuel pump wasn't running and heard the relay making a buzzing noise. Replaced it, still no fuel pump. I then checked back at the pump for power and there is nothing. I tried to decipher the wiring diagrams for it off of AllData, but to no avail. I have no idea what to try next. . .anyone got any suggestions??? I'm at a total loss! please help! Thanks in advance!

bro460

My suggestion will be to get a bucket or something for gas to run into. Undo the fuel line before it goes into the filter and see if the pump will run. Maybe the filter is plugged??? Is there power right at the plug where it plugs into the pump harness? If there is power to the plug and still no feul pump then the wiring to the pump maybe even in tank is bad. You can even try and sorta jump start the pump by wiring 12v right to the plug and see if the pump runs at all.

bro460

Also even if the pump runs I would pull the gas tank and get it flushed out. Car that sits for 9yrs is probably garranted to have water or varnished fuel. Might be a concern also with injector, they might be gummed up.

I used to have a 86 4000 cs Quattro 5cyl 5spd. AWESOME CAR!!!!! I just bought a 98 A4 1.8TQ and so far I really miss my 86. That is a real Audi, not a VW with sheepskin. Don't get me wrong I do really like my new Audi thou. Just not the same feel. ENJOY your car and I hope I've helped.

gatorade1987

Hey thanks for your input. I know the fuel pump is fine because it's brand new and I've tested it. It's not a cloggged fuel issue because the pump doesn't have power. The main wiring harness is the problem (no power going to the fuel pump) but I just don't know where to start on it. Another strange thing is if I jump the fuel pump relay to "full on" the fuel pump fuse still doesn't have any power, hense the fuel pump harness still has no power. . .it doesn't make sense to me. is there a main cut-off relay or something that maybe is shot? I'm just not tracking how this car is wired. BTW there is continuity from the fuel pump harness up into the car under the dash. So I know I don't have issues with a mouse eaten wire or anything under the car. It's all from the dash forward and everything appears in normal working order right there. Any thoughts???
I'm glad to hear that it's such a fun car!!! I'm really looking forward to some road time with it! One of my friends had a 98 A4. . .it was the car that made me fall in love with Audi! Thanks again for your suggestions.

bro460

Hmmmm, Just an idea. Have you checked the fuel shutoff swith (inertia switch). Also have you tested the continuity between the relay and the ecu? is there power coming out of the ecu on the fuel circuit? Is it maybe a ecu problem?

gatorade1987

Hmm, that sounds like some good possibilities. . .where is the inertia switch located at? Do you know how to test for power coming out of the ecu on the fuel circuit? that was kinda what my gut-reaction was leaning towards, but I couldn't figure out how to check it. Any input would be great, and hey, I really appreciate you taking the time to help me figure this out! Also, one more question, would a bad hall sensor (the switch on the distributor that tells the fuel pump when to turn on [450rpms minimum I believe] or off) cause this problem or no?

latchkeykid

Couple things...

There is no inertia switch.

Have a look at your fuse box, verify every last one of the fuses is good and then lift the whole panel up out of container and check that the leads going to the fuel pump relay harness are still connected. Now if that is all good and it most likely will be then I'll put a small bet on the fact that your ignition switch has failed internally. It happens ALL the time and its a 20 to 30 buck part at best. The thing is made of plastic, cracks and then fails to make the final contact in the circuit.

For shitsngiggles you can always run power directly to the pump via a spare battery and some careful wiring "just" to get it going.

latchkeykid

Couple things...

There is no inertia switch.

Have a look at your fuse box, verify every last one of the fuses is good and then lift the whole panel up out of container and check that the leads going to the fuel pump relay harness are still connected. Now if that is all good and it most likely will be then I'll put a small bet on the fact that your ignition switch has failed internally. It happens ALL the time and its a 20 to 30 buck part at best. The thing is made of plastic, cracks and then fails to make the final contact in the circuit.

Are you sure that Hall Sensor on the distributor has anything to do with the fuel pump circuit?

For shitsngiggles you can always run power directly to the pump via a spare battery and some careful wiring "just" to get it going.

gatorade1987

Thanks! that sounds like what Ive got going on. i have run power directly, and gotten it started, I just didn't want to "hardwire" it. I had previously checked all the leads going into the fuel pump relay for continuity. They're all good (as are all the fuses). I assume you're talking about the ignition starter switch, and not the actual "lock and key cylinder" right? Thanks for your input! I'm going to assume that I have to pull out the ignition cylinder to get to it right?

gatorade1987

Oh and one more question. . .if the ignition starter switch is bad will I still get power for lights and everything? (the car even turns over, just won't fire do to no fuel pump power) or would nothing work?