cghag1

I posted a question about two weeks ago regarding a stalling issue on a '91 100. I was finally able to check the cods and all I got was 4444, so no luck there.

I hear the fuel pump run for a few seconds when I turn the key to the ON position. It will start right up and run briefly before it dies. In the 30-45 seconds that it runs the car will accelerate properly for 5-10 seconds before all but stalling. I can keep it alive by carefully pumping the throttle until it accelerates again. This sequence continues 3-4 times, but each time the period of acceleration shortens and the period of low RPM's gets longer and lower until it eventually stalls.

I was able to milk it home from my daughter's apartment to my house by doing this procedure a couple of times. But I'm onlt talking three blocks total distance. I got half way the first time before it died and I pushed it into a parking space. I went back several hours later and made it the final two blocks.

Where should I look next? TIA.

Dave

audiqv8

Remove the fuel pump replay and use a jumper to see if the car runs normally.

cghag1

I assume we're talking about the relay in the main fuse box, the same one I had to use to check codes? What two leads do I need to jump?

I'm No Pro

I assume we're talking about the relay in the main fuse box --- YES

the same one I had to use to check codes --- YES

What two leads do I need to jump--- Put a spare fuse in the slot on top of the relay

cghag1

So, rather than pulling the relay as suggested by audiqv8 I can just put a spare fuse in the top of the relay? Sounds simple enough.

What should happen when I do this? The pump will run continuously?

Sorry for asking a bunch of questions. I'm just trying to understand the process. I need to break down and buy the Bently manuals, but my other daughter just banged up her '85 VW Cabriolet moving that car issue to the top of the priority list.

Thanks for your help everybody.

I'm No Pro

What should happen when I do this? The pump will run continuously? Yes

I think this is a way to rule out the fuel pump relay as the problem with your car. If the relay is your issue you are in luck - simple you probably won't even have to wash your hands after you're done.

Remember - I'm no Pro

boxerfan

Check ISV and WUR. That's my $0.02.

Katman

Putting the fuse in the fuel pump relay tells the ECU to turn on the fuel pump all the time (for testing purposes). There is no direct connection between the fuse and the relay, except for ECU logic.

So... If the relay IS borked, then even with the fuse in the ECU telling it to turn on, you may still have a problem.

Two ways to cheat:

1) Jumper all the 'big' terminals together. (THe 'center row' when looking at the relay socket from the fender side of the fuse box.)
This would be the best way to prove a defective relay.

2)Or.. Open the relay, and force the 'part inside that moves' closed, with a wad of folded up paper or such. That will make it act as if it's actuated, even if it isn't.

S4for73

WUR is probably plugged and providing NO pressure to the fuel dizzy. Boxerfan is right. Remove the screen and see what happens?

cghag1

OK, now is when I feel like an ignoramus. What is the ISV and the WUR?