A friend and I have gone in together and bought an '87 IROC to get running and turn it around to sell. It's got the 5.7 TPI engine. After removing a nightmare of accessory wiring that plagued the electrical system, I have finally gotten to a point where the car will crank over, and run. But it will only run for a very short period, like about 3-4 seconds, before it sputters out. Then while trying to start it immediately afterward, it only tries to fire, but won't run. If I let it sit for bit, it will start again, but again for only 3-4 seconds. There is fuel in the fuel rail, but I don't have a gauge to test for pressure. Is the fuel pump audible at all when the key is first switched on, before cranking? I can vaguely remember my old S-10 Blazer having some sort of noise from the pump, but can't remember for sure. Anyway, when the key is switched on, I get no noise at all.

 

Hey, new guy.....
the fuel pump will come on to pressurize the system when you first turn the key on. However, if you turn it off and wait less than 30 seconds or so (I forget the actual time) before turning it back on, it won't do it again. You must wait a bit with the key off, before turning it back on to get it to pressurize the system again..... if my explanation makes any sense......
But like you said, the only real way to get a good idea of what is going wrong is to get a fuel pressure gauge.

 

So by your answer, am I to assume I should hear something back there? Thanks for the response!

 

yea mine builds up pressure after the car has already turned off and is sitting is that spose to do that??????

 

OK well unfortunately on mine I had the same problem. First I thought it was my fuel filter. I removed it and it was horrible looking. Rust everywhere from the gas tank. So take it from my dont drive on E. But it was actually my fuel pump. It would do the same thing. Start up for 5 seconds then die. I would try to give it gas and it would die. Check your fuel filter first and also the fuel pressure.

 

Josh, it should build the pressure when you first turn the key on and the fuel pump runs for a few seconds (I'm going to call this 'priming the system' for lack of a better term). The fuel system and rail should hold that pressure for a while (unfortunately I can't tell you how long because mine does not hold pressure, but I think it should be like a half hour or hour or even more). If it does not hold pressure and the pressure drops off immediately after the fuel pump 'primes the system', your fuel pressure regulator could be leaking or possibly a bad check valve in the fuel pump itself. But none of you described that problem.
I have had some fuel pumps do some really weird stuff when they're going out. Last year in my Iroc, fuel pump would work fine when I first started the car and fine while I drove it, but when I shut the car off, it wouldn't come on again until I let it sit for a few hours.
You can find the fuel pump relay and make sure that it is giving out a good 12v when it is 'priming the system' and while you are cranking the car to eliminate a bad relay. Every time a fuel pump goes out on me I try to check everything to avoid pulling the tank, but I always run out of options and it does end up being the fuel pump. With that said, newguy, I'm not saying your's is definately the pump as I have not had one act like that before, but I've only had 3 or so go out on me.
If you turn the key on, it should prime. Turn the key off for about a minute or two, then turn it back on, it should prime again.

 

Right, but what I'm still needing to know is, should I be able to actually hear the pump running while it's priming the system? Also, where can I find the fuel pump relay? There are a few relays on the firewall on the driver's side. Is it one of these? Luckily for me, my buddy in this deal with me is not the mechanical type, so he pays for the parts, I just have to put them on. Thanks!

 

Yes the FP relay is on the firewall where you described it. If the car has AC, I think the relay is the same part no. as the AC relay which is right next to it. If the P/N is the same try switching the relays.

You should hear the pump "priming" for ~5-10 seconds when you turn the key on after the car's been sitting a while. When the engine is warm, the pump may not "prime".

 

Thanks! I'll try the relay trick

 

Vader has been so nice as to label those relays for us.... LINK

 

Awesome! Thanks for that link. It clears up a few questions I had about wiring schematics.

 

I had forgotten which was which, so I did a search before I replied and dug up that thread. I remembered seeing that pic or one like it from last summer when I was having fuel pump problems....
Good luck