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working on a 1995 LT1 out of a camaro (i know there's camaro boards, but i got no help there) and i put an aftermarket fuel pump putting an unknown amount of fuel pressure to the rails. I think the pump puts out 55 psi or maybe more. I think the fuel pressure for the engine should be 43.5 psi.
Problem im having is the engine is running so rich it wont stay running.. It chokes out and smells like a carb that is flooded. I thought that since it was open headers it was reading too much O2 and richening up the mix too much, but now ive got exhaust on it its still doing it. SOO.. did the computer "learn" too much o2 and hasnt forgotten it yet, or have i overwhelmed the factory pressure regulator with too much fuel and the injectors are just dumping it in the engine?
I know i need to get a pressure gauge and check it, and then probably a aftermarket regulator, but then would i take the vacuum line off the factory regulator or leave it? I've got so many questions...
What have you done to the car, more info would help. I do not think the fuel pressure being too high would really cause this problem. Are the injectors stock or ?
the battery is disconnected each time i stop it, as im not too trustworthy of the vehicle yet. it was disconnected while he did the exhaust. Basically, bjankusky, its a factory 95 camaro engine (cam plus whatever i cant tell) dropped in a 62 chevy c-10 with wiring harness. i used a bosch fuel pump that was supposedly from a corvette and a fuel filter with a return in it to handle the fuel incjection need for a return. I know the pump/filter return setup worked for a 360 FI system my father ran in an old dart, but i dont know what fuel pressure it throws or what his needed. I dont know what this one is doing now either... i think the injectors are stock - they look it.
A BIG question is that if the regulator were GOOD, could it bleed off enough pressure to compensate for a 55 psi pump or even more? This thing smells like a flooded carb when running and when it dies. I got the exhaust put on today, and it drove fine for a bit (smelling rich) and after maybe 2 miles, it started to bog down - like the more pedal I gave it, the more it gagged and choked like there was way too much fuel. Only at idle would it run, any pedal and it would die, then it died at idle. This is after it is warm - it seems (ive not run it often enough hot) that it runs like garbage hot and better cold. it does have the o2 sensors intact
Last edited by matthewsorrells; Nov 17, 2016 at 06:48 PM.
If you have a FPR on the fuel line, the pump will only put out enough pressure to open the FPR, not 55+psi. That's why it's called a FPR! You definitely need a pressure gauge.
If you test that fuel pump with the fuel dumping directly into a bucket, with no restrictions in the fuel line, the fuel pressure will be just about zero!
What do your spark plugs look like? Have you checked your injectors to see if one might be stuck open? You'll definitely have a sooty looking spark plug, or are they all fouled?
ok - here's some info. upon discussion with dad (68 years old with communication issues but thats another story ) it appears that i have the fuel filter/return set up wrong. The way i have it plumbed is putting the return from the fuel filter/return to the return line from the FPR so it cannot regulate itself either way. I need to take out the filter/return that i have in there and simply run the factory return back to a "T" before the fuel pump so it can relieve the pressure. Maybe weve figured out the problem..... but maybe that problem wont solve the problem im having totally, i dont know, but i know its a problem. Did that make sense? lol
I need to take out the filter/return that i have in there and simply run the factory return back to a "T" before the fuel pump so it can relieve the pressure. Did that make sense?
Sorry, that doesn't make sense to me. Here's a link that might explain what you want for a good fuel line path. It's geared for turbo engines, but the theory is the same for your car. Your fuel return line needs to go back to the fuel tank, not to a "T". turbosmart.com.au/technical-articles/how-does-an-fpr-work/
Hot Rod Roy, I dont understand what would be the difference if it went back to the tank (with NO place to put the return) or back to any point pre-fuel pump. The fuel pump pulls a vacuum on the line going into the tank, so going into a T in the line before the pump would have the same effect, wouldnt it? I'm not trying to be difficult, but there is no return or vent in the fuel tank.
What I'm suggesting is to remove my aftermarket return and regulator and pipe return line from factory regulator back to pre-fuel pump input. There wouldnt be any air bubbles in it, and any fuel that the pump does not pull through would reverse the flow of fuel back into the tank while pump is not running. Why would that not work? I know thats not ideal, but with no return into tank, the options be limited!
oh, and Roy - its not a factory fuel pump. Supposedly its out of a corvette (hey - it was free) and its a Bosch. Looks just like this one (https://www.pegasusautoracing.com/pr...zWkxoCsOzw_wcB) and its website says that it has the MOST flow at 0 psi.
Ok you will need to find a safe way to do this. With the setup you have you are putting out way to much pressure. Look where the line comes out might be a port there or change the insert.
Last edited by antfarmer2; Nov 18, 2016 at 10:22 AM.
help on fuel pressure please
