fuel issue
Thread Starter
Burning Brakes
Joined: Nov 2008
Posts: 1,159
Likes: 31
From: Orange Park Florida
fuel issue
Hey, I recently had some fuel go bad because I was unable to tend to my 1987 C4 through the winter. I drained the tank and filled about 5/8 full with new gas. After getting the battery charged good which had been on a maintainer I tried to fire it up. No luck and I noticed the fuel pump was not cycling for 2 or 3 seconds, and no fuel at the fuel rail. I proceded to verify that fuel pump fuse was good and it was fine. I believe the 2 or 3 second prime is controlled by the ECU at start up... I guess I will pull the fuel pump and test it thinking maybe fouled gas has froze it up. Can anyone think of anything that I may have missed? Car ran fine when I last ran months ago, Thanks, Gary
Team Owner
Joined: Jul 2004
Posts: 28,376
Likes: 3,260
From: Hartford WI
Why exactly is it bad? IIRC, I have left gas over the winter before and it isn't good but hasn't screwed up pumps or things like that. Might not be as powerful but completely dead, I don't think so.
When you turn the key, it should cycle. After that, subsequent turns of the key WILL NOT CYCLE for a few minutes. Not sure about the duration but repeatedly turning the key won't make that thing prime. It has to settle for a few minutes. So if you leave it for a bit, put a DVOM on the pump connectors (right ones) and have your assistant turn the key and see what happens. After that, I think you can try short the pump to see if it even works before replacing it.
When you turn the key, it should cycle. After that, subsequent turns of the key WILL NOT CYCLE for a few minutes. Not sure about the duration but repeatedly turning the key won't make that thing prime. It has to settle for a few minutes. So if you leave it for a bit, put a DVOM on the pump connectors (right ones) and have your assistant turn the key and see what happens. After that, I think you can try short the pump to see if it even works before replacing it.
Thread Starter
Burning Brakes
Joined: Nov 2008
Posts: 1,159
Likes: 31
From: Orange Park Florida
Thanks,for your help... I kinda figured what you explained but wasn't totally sure how it all worked. I looked in the fuse box for a fuse marked FP or something similar and did not find one. There is no reason to feel like one would be blown the car ran fine when last ran. And I do recall after my wife reminded me, that I had started and drove the car mid winter here in Florida. We don't actually have a winter here, they just call it winter. Any way I listened real good for the prime when I first hit the key and in case I forgot to mention the battery was very weak. I had kept it on a battery tender especially on the few nights that it did get cold bur it seemed it would have maintained the battery better. I charged the battery and was getting a voltage of 13.7 and checked the fuel rail which had no fuel pressure. I am going to charge some more in the morning and try to see if it will prime. Thanks again, Gary
Thread Starter
Burning Brakes
Joined: Nov 2008
Posts: 1,159
Likes: 31
From: Orange Park Florida
4/21/21 update, I removed the old fuel pump which the filter sock had fell off of. I had drained the old gas and put fresh gas in the tank. The inside of the tank was spotless and I noticed the assumption that about the gas going bad was wrong. I tested the pump and it was bad so U ordered a new pump and installed a working good spare that I had. My battery voltage was low so I am charging battery now. Gggg
