My LT1 died cold about a month ago, and I've let it sit while I accumulate parts to do several upgrades while it's down. I've almost got what I need, so I'm getting ready to get it back in the world of the living.

However, it appears the final cause of it quitting altogether was the fuel pump. I have -0- fuel pressure. The odd thing is that it will start and idle fine for about 3-5 seconds once every 2-3 days. Then it won't fire a single bit for at least another 24 hours.

So I did some experimenting by leavng the fuel pressure gage on it while I did all this. For the 3-5 seconds it cranks and runs, it has just bareley enough pressure to hop the pressure gage off the peg, but less than 5psi. After it dies, key on, cranking or not, -0- pressure.

I need to check to make sure the fuel pump relay is actually working, but it seems that for there to be ANY fuel pressure, the relay would have to be working and the pump giving the slightests effort every now and then.

Unless... I'm wondering if the car sitting in the sun and heat for a couple of days builds up just enough pressure in the tank to force the 3psi or so I'm seeing every couple of days that makes it idle for a few seconds. Which could still mean the relay OR the pump.

So if I find that the relay is in fact sending power to the pump, is it undoubtedly the pump, or is there another circuit between the relay and the pump that could be bad that I also need to check before replacing the pump?

And in the case that I need to replace the pump, are there good aftermarket alternatives? Anything with a performance gain, or do the aftermarket units just provide longer life?

Thanks in advance!!!
Paul 'X'

 

There's a fuel pump test connector up by the PCM. Connect a fused 12V source. It bypasses the relay, so that will tell you if the pump is capable of operating, and if it is, you will be able to see the pressure.

 

Thanks Man!!! I tried it and got nothing... Looks like the fuel pump is a goner. Also, I've left the fuel pressure gage hooked up for about a week now watching it, and after sitting in the hot sun all day, I noticed that it was carrying about 3psi again. I didn't try to start it, but I'm sure it would start and idle for 5 seconds as it has for a month or so now.

Now, can anybody tell me about aftermarket fuel pumps??? Any performance gain or just more life out of them? Or just go with a new GM unit?

Thanks!

Paul 'X'