My 96 runs fine for about 5 minutes then it loses all power and dies. I put a fuel pressure gauge on and it starts out fine but is around 45psi when it dies. It has a new fuel pump and filter, cap+rotor, plugs and wires. I had a GM tech look at it and he said to remove my aftermarket alarm and remote start. I plan on doing that but I thought it was an ignition switch. The problem is it doesn't start after ten minutes, it takes up to a few hours. I'm about to just give up and take it to a shop. If anyone's had this problem I could use the help.
Thanks

 

What pressure is it at when you say "it starts out fine" and how long does it take to drop to 45psi? What is going on when it drops to 45psi?

It is quite possible that the ignition switch is to blame.

 

Wouldn't be the first time i've heard of a doa/short life fuel pump... Where are you testing your fuel pressure? I've read other threads that talk about capping it off at the intake and taking a reading, but I am not sure how this would work if you need to get the pump warm. Maybe the use of a T valve for the sake of testing?

 

I test it at the schrader valve next to the distributor cap. It was running at just under 60 psi for about five minutes when it would stall and die. When I would give it gas it would bog down and sputter.

Now its not starting at all and the pressure hits 30 psi at the most. I guess it's possible that I screwed something up when I took the alarm and remote start out but I don't think that's it. The pump should still be under warranty so I'm probably going to get a new one tomorrow and see what happens.

 

A couple things to check before you shell out the 300 bucks or so for a new fuel pump. First thing is to check the voltage at the pump. There are 4 wires that go into the pump. Two thin ones and two thick ones. The two thicker ones power the pump and the other two are for the fuel gauge.

Just a note: On most of these trucks if you drop the spare tire you can get at the wires and fuel lines much easier. Also the pump only runs for 2 seconds after you turn the key unless the engine starts so get a helper.

If you do not have 12v at the pump then the next step is to check the fuel pump relay under the hood. The easiest way is to simply swap it out with one of the many identical relays (check the numbers on them first) such as the fog lamp or horn relays.

If you do have 12v at the pump (regardless of how much you wiggle the wires around) then in all likely hood your pump is starting to fail.

However, you can still rule out other electrical issues and fuel pressure regulators ect.. by supplying 12v to the pump directly and testing it's output directly at the source. The largest of the 4 output hoses on the pump is usually where you will hook up your pressure tester.

If it checks out fine there then you can move on to testing other things before replacing what might be a good pump.

 

Thanks for all the advice. I did some testing and decided to go ahead and change the pump again. That ended up fixing the problem. It runs great and holds pressure.
BUT.. when I was changing it I screwed up and somehow there's a pinhole in the feed line between the tank and filter. I don't have the cash right now to get a new line ($120) so is there any safe way to patch it for now til I can get it replaced? I put some JB stick weld on but it lasted all of five minutes.

 

It may sound like something from the south, but I would try wrapping a bit of Teflon tape around it, then splice a piece of vacuum line (and put it around the fuel line) and clamping the crap out of it... If it is in a place you can do that...

 

You could cut out the bad section, flare the cut ends, and splice in a replacement line using couplings.

This is far less expensive then replacing the entire line and the tools needed can usually be rented from many auto parts stores. This is essentially the same procedure as splicing in a new piece of brake line.