Hi all,

I did a search and couldn't find anything, but I've got a big issue that needs to be fixed a few days ago. I've got a '96 LT4 car, but the fuel system should be the same as an LT1, so you guys can chime in as well. My fuel pump doesn't appear to want to give me any pressure, but sometimes when I turn the key the pump will kick on for a split second.

To start the story off, I was letting the car warm up so I could change the oil and it suddenly died. I did some diagnosis and it turns out that the there was no fuel pressure. I've got a gauge attached to the fuel rail. Long story short, there isn't 12 volts getting to the pump. I don't hear the pump click on when I turn the key and it doesn't click on after extended cranking (this should rule out the oil pressure switch).

I replaced the pump thinking that it could just be dead, but that didn't solve the problem. I've checked for 12 volts at both the 10A fuse on the passenger side of the car and the 20A fuse under the hood. Neither had 12 volts. Both had 12 millivolts, however. I checked both for when the key is turned initially, there should be 2 seconds where the pump is running and 12 volts should be present, and I got nothing.

What wires should I be checking on the actual fuel pump for the voltage? There are three wires there, but I'm only one guy and I didn't have the ability to turn the key and check voltage at the same time.

Now, I also have a spare computer, so I tossed that in the car and nothing changed. So thus far I've ruled out an actual pump problem as well as a computer problem or an oil pressure switch problem. I also switched the relay with a known good relay and the same thing, so it's not the relay either.

I'm wondering if anyone knows how to properly test a relay for this kind of issue, and if there are any proper procedures I should be going through. I have the service manual, but I have none of the tools that they keep referencing, nor do I have the Tech 2 system to plug the car into and check things that way.

Are there certain pins on the OBD2 connection that I can put 12 volts to in order to start the pump? Any other tests I'm missing? How should I go about putting 12 volts directly to the pump? Which slots on the relay should I be jumping to get the 12 volts directly to the pump? I really have no idea what else to check or where to go with this. Any help is appreciated. I'm thinking it's a connector somewhere, but again I have no idea what to check further. This car makes me miss my 66 nova, I'd have that fixed and on the road in 10 minutes flat.

 

Yeah if you are not an electrical guru (I am definitely NOT) they can get frustrating.

If you are racing (from the look of your avatar you are) you should probably look into the Racetronix kit anyway:

http://www.racetronix.com/RX-C44-FPWHG-2.html

 

Here's a bump... No one has any ideas? I do like the look of that wiring harness, that may solve the issue but I'm hesitant to replace something unless I know it's the problem.