I posted this on hp tuners so Im going to copy on here and see if anybody has had issues like this. Thanks.

Ill start from the beginning. I have a 99 Camaro with a racetronix fuel pump setup I've been working on tuning and ran into a issue a week or two ago of the fuel pump just cutting out. I was driving up the road and got on it a little and then when I let off it had no power and cut off after a few seconds, I pulled over and found I had no fuel pressure and the pump would not prime. I was checking things out and then after a min or two it primed up and started with no issues, ran it the rest of the day and did not do it again. A few days later I drove it and same thing, I got on it and it just nosed over and died, after a few mins it started right up like nothing happen. Today I was about to go out and do some datalogging and it died pulling out of the drive, this time I started doing some diag on it while the issue was present. Found the fuel pump is perfectly fine, no holes in any lines, connections are good. Checked voltage at fuel pump relay and voltage present at one pin and when key is turned on voltage is present on the other (forget the exact pin #'s). Switched relays, no fix. Was back at the racetronix relay in the back for the booster and it started to work again. Has anyone ran into a issue like this? Is there something in the computer that will cut off the signal to the fuel pump? Also if a tps sensor is going bad or is bad what kinda issues will that cause, I drove it after it started to work again and it was cutting out (caught it on the logger as a tps dipping out). Could these be related issues???

Ok, update on this issue. Put a new tps sensor in cause I was catching that on the datalogger blipping out so I got that fixed, is not related to fuel pump issue though. I can get it to cut out when I power brake it or put it under load. Checked the voltages at the fuel pump relay under the hood, all was good and still had a issue. checked the fuse inline on the line from the alt to the relay in the back for the booster and it was good, then it started to work again. Did notice the the fuel pressure climbed up when primed but then fell right back to 0. When running it stayed at 58 psi, then I power braked it and it fell to 0 and died. Tried to start again and fuel pump never cuts on.

 

Have you checked your fuel pressure regulator? I had the same problem on a LM7. Replaced FPR and issue got better but in the end replaced the pump.

 

Check the fuel pump relay. I would just change it to be safe. They aren't that much I had the problem and my relay was going bad and once it got so hot it would cut out just like you are talking about and when it cooled back down worked like nothing was wrong.

 

Also check the fuel relay that is behind the kick panel on the drivers side as the one under the hood. you can also check ground 305. It's located in the middle of the drivers side rocker panel near the driver's seat. I've seen a couple cars break that ground, and one broke all but 2 wire strands that would overheat within a few minutes of operation killing the pump.

 

I am going to be ordering a new fpr because from what Ive seen is the fuel pressure should hold after it is primed and it drops to 0 right after. Also I will get new relays just to be on the safe side too. Havent checked the relay behind the kick panel yet, need to go find that one and see. This morn I had meters hooked up to all kinds of places to see if I could see where it would blip out but my luck the dang thing never acted up. On another issue that is a pain in my *** is that the radio goes out every once in a while and when it does my windows wont roll up or down, is there a common ground or power that runs these somewhere? Had this issue for a while and never really looked into it.

 

This. Mine kept randomly dying and not priming and then would magically start after sitting over night. Finally got to test the relay when it died the last time and that was it.

 

This might be your second issue.

https://ls1tech.com/forums/general-m...blems-fix.html

 

For the radio and the window thing, that is probably your BCM (Body Control Module) its located under the passenger side dash. You have to take the kick panel off and some other things to get to it. Look up BCM fix something should come up for it. It has a solder point that gets messed up on the board and needs to be resoldered.
This should help you fix it. http://camaroforums.com/forum/93-02-...-repair-52062/

 

Probably it but if the FPR doesn't fix the pressure loss problem, #2 would be leaking injector or#3 leak in the rail somewhere. FPR is where to start though.

 

I appreciate the help. For the radio and windows I did look up the BCM fix and knocked it out real quick and haven't had a issue with it so far (it did have a crack in the solder points on that board). I have a fpr on the way and a relay also just to cover my bases, Ill update y'all if this cures my issue or not in a few days when I can work on it.

 

Good. I'm glad the BCM fixed the radio. I can't stand driving without mine haha

 

Alright, I have a new fpr in it and go to start it and let it prime and fuel pressure goes up and then comes back down. Turned the key twice and had 58psi and in 5 secs its back to 0 so there has to be a leak somewhere, no visible leaks and injectors are brand new, as is the whole fuel pump setup and lots of other things. Did replace the relay in the kick panel and swapped the one under the hood with other ones. I could not get it to die a few days ago (before the fpr and relay) and still couldn't get it to die today. I drove it down a back road and opened it up, felt like riding a bull when I did, fell on its face then came back then dropped off again. Drove back home and had someone power brake it and watched the fuel gauge on my fuel rail and sure enough, fuel pressure dropped and fell on its face and stumbled. Had the datalogger going when I got on it going down the road and it shows it leans out so I assume it loses fuel pressure when I did. So Im going to take one problem at a time, what would cause it to loose fuel pressure under heavy load for one? and need to find a leak somewhere for two.

 

This should be in the fuel injection section, not the INTERNAL ENGINE section.

https://ls1tech.com/forums/fueling-injection-8/

 

Paul, can you move this so we don't lose all the responses already?

It occurs to me that you could have a vacuum issue to the FPR.. When you stomp the throttle, vacuum at the FPR should be low and cause the pressure to rise. If that doesn't happen and the computer opens up the injectors based on the TPS or RPM readings, there might not be enough fuel pressure to maintain. My $0.02.

Can you smell gas anywhere?

 

No worries, it's here now with followers.

Next time, we disable you car remotely.........

 

This has the fpr in the tank on this one but there has to be a leak in the line internally or a injector leaking because of the pressure dropping just after priming it, or does this have some sort of check valve in the pump that could leak off too. The loosing pressure while running is whats gets me. Just idling there it has 58psi but start to power brake and it will start to loose pressure or drop to 0 and bounce around. I don't smell any fuel or see any leaks. I appreciate all the help thought.

P.S. I just got on this forum and haven't looked around to see all the stuff on here so I just put it in this section, looked like a nice place to put it. And if you disable my car remotely Ill never know cause its not running right anyways lol

 

Maybe he already did..and we're just chasing fuel problems!

There should be something in there akin to a check valve and this would either be in the fuel pump or in the pickup assembly that holds the pump and such.

See the following thread about check valve.. It's in the wrong forum too(GIII external engine; closer but still not in fueling) but there's some guy named Paul that posted on it anyway..

https://ls1tech.com/forums/generatio...eck-valve.html

Good luck!

 

Sorry If I left anybody hanging on here, been busy for a while. I did find the issue with this thing though. The whole issue with the fuel pressure leaking down and stuff was from a leak at the plastic line from the pump up to the top of the fuel pump housing (it wasn't the line or where the line met the top of the housing), it was where the two pieces of plastic was fused together that the line connects too. Ended up having to get a new fuel pump assembly and fitting my pump into the new one to fix this.

The issue with power cutting off to the pump Im not positive about though. It could have been the relay behind the kick panel but after I fixed the leak I haven't had a problem with that again.

Thanks for all the help

 

I'm glad it's resolved, now let's get cruising!