Hey guys... this is my first post on here but I've been a big lurker since picking up the Camaro about 2 months ago. There's some good stuff on here to say the least....

I'm a big fan of forums... and I know how obnoxious it is when new people come on and hope that the guru's on here can just spit out all their answers. I have searched TONS on this topic and still can't quite figure it out. Here it goes...

92' RS... TBI. I was told by the previous owner that he had just replaced the fuel pump to solve an issue with it not starting after he'd left it sitting for about 3 months. Well... I get it home just fine, but then I come to find that sometimes it starts, sometimes it doesn't. I questioned whether or not the PO actually did that work, so I decided to check it out myself.

When it doesn't start, the pump just doesns't energize. When I went to do the work of dropping the tank and installing a 4th gen rear I came across, I tested the circuit some when I had also pulled off the fuel filter to eliminate the possibility of it being anything engine related.

At the start of the testing, it wouldn't prime. Jump the relay harness, won't prime. Test the C313 (I believe that's the name...?) on BOTH sides of the connector, and on each side when checking for voltage between the pos and ground wire, I'd get 12v.

This would lead me to believe that it's something between the connector and the fuel pump, obviously.

Well, when I removed the tank and hooked the c313 connector end directly to a 12v source, it works properly. No wiggling of any contacts created even the slightest glitch. I cleaned all connections anways, put in new strainer, and set it up to go again... figuring that the problem must be elsewhere on the car.

The car started consistently about a dozen times after that and getting it all back together. Much better than before. When I go to take out the car for a longer drive tonight, after about 30 minutes, it randomly dies on the highway. I go to start it back up while still rolling, fires right back up. Take the next exit to turn around, and after turning around, the car dies again before I get back on the highway. Try to re-start it, and it won't do it. Get ready to call a tow, and right before I finalize the tow, it starts right up.

It seems to me that the problem is directly related to the fuel pump circuit, but I just can't seem to pinpoint where. As soon as I go to start the car, I can either hear the pump prime or else I know it won't start.

Is there some control over the ground circuit that I'm missing?? It baffles me how the connector could read 12v on each side of the connector, but not engage the FP... while applying a 12v source while outside the car will fire the pump right up.

Any suggestions, as always, are greatly appreciated...

 

Vats circuit? Is your security light on? Does it come on briefly when you first turn on the key? Just a thought...

 

I thought about the VATS and looked into how that circuit works, but to my knowledge the VATS will disable the fuel by not sending a pulse to the injectors, but that it doesn't interfere with the fuel pump at all. My issue is that sometimes the power to the fuel pump is interrupted. You'll hear that it won't prime...

 

Anyone??? This is what's holding the Camaro up from being my DD... AND selling my current DD which needs to go...

 

.
.

.
.

 

The fuel enable signal is what triggers the contact at the fuel pump relay, correct?? I'm inclined to think that this is a grounding issue from the C313 harness to the chassis... does anyone know where that grounds out at?? Because even when I had the relay socket jumped with a clip, and the harness showed receiving 12v, I still didn't get power.

 

....anyone??

 

it may be a ground problem, I tend to think it is the VATS, if the injectors are not receiving a signal, there will be no signal to the pump,

Waite that is what my daughters Camaro, I almost forgot it has been 4years ago that we sold that car.

it is the fuel pump going bad.

 

If the injectors are not receiving a signal, there will be no signal to the pump?? Now that just doesn't make sense to me. When the pump will randomly not run, it won't even prime. It's my understanding that the charge to the fuel pump is totally independent of the signal to the injectors. Am I off on this?

When the pump cuts out, it just doesn't do anything. No attempt to prime at all. And then when it DOES run, the fuel pump supplies a good steady pressure for as long as it is going... until it will randomly cut out. That sounds like a fuel pump going out rather than an electrical issue?? Seems that if it was going out, it wouldn't run correctly off and on as it does...

 

Just as a follow up, I replaced the fuel pump and the sending unit. The likelihood of it being the sending unit is pretty slim, so chances are it was the fuel pump, as it's been fine for about 2-3k miles since.