fuel pressure.
Thread Starter
Instructor
Joined: Sep 2015
Posts: 143
Likes: 25
fuel pressure.
Hello,
92 lt1. Finally checked fuel pressure. Turn key to run. Had 10 psi. Started car, went to 40 psi. Removed vacuum line at fpr, went to 48 psi. Replaced vacuum line and stayed a steady 40 , going to 43 psi when I rev the engine. Shut the car off, and drops 40 to 0 in less then a minute. No fuel at fpr, and maybe the car starts a bit slow the first time sitting for a couple of days ? Drives good, and idles good. Starts right up all the time. Could it be a bad check valve in fuel pump ? And what If I also had a bad fuel pump relay ?
92 lt1. Finally checked fuel pressure. Turn key to run. Had 10 psi. Started car, went to 40 psi. Removed vacuum line at fpr, went to 48 psi. Replaced vacuum line and stayed a steady 40 , going to 43 psi when I rev the engine. Shut the car off, and drops 40 to 0 in less then a minute. No fuel at fpr, and maybe the car starts a bit slow the first time sitting for a couple of days ? Drives good, and idles good. Starts right up all the time. Could it be a bad check valve in fuel pump ? And what If I also had a bad fuel pump relay ?
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Fuel pump check valve is most common cause. If FPR diaphragm is leaking; fuel would leak from hose when disconnected and engine is running. If you remove well at fuel tank filler it possible to block off fuel lines to isolate source of leak down.
Thread Starter
Instructor
Joined: Sep 2015
Posts: 143
Likes: 25
Hello,
I replaced pulsator with fuel line last year. No leaking fuel at fpr. I don't think the injectors are leaking as many times as I have looked for leaks or drips. I think it would be a massive fuel injector leak to lose so much pressure so fast ? I'm going with the crazy , crazy ideal that when I take the fuel cap off the fumes are overwhelming, like the gas is being poured in the tank ? thinking new fuel pump and sock in the near future ?
I replaced pulsator with fuel line last year. No leaking fuel at fpr. I don't think the injectors are leaking as many times as I have looked for leaks or drips. I think it would be a massive fuel injector leak to lose so much pressure so fast ? I'm going with the crazy , crazy ideal that when I take the fuel cap off the fumes are overwhelming, like the gas is being poured in the tank ? thinking new fuel pump and sock in the near future ?
Team Owner
Joined: Jul 2004
Posts: 28,463
Likes: 3,288
From: Hartford WI
Hello,
I replaced pulsator with fuel line last year. No leaking fuel at fpr. I don't think the injectors are leaking as many times as I have looked for leaks or drips. I think it would be a massive fuel injector leak to lose so much pressure so fast ? I'm going with the crazy , crazy ideal that when I take the fuel cap off the fumes are overwhelming, like the gas is being poured in the tank ? thinking new fuel pump and sock in the near future ?
I replaced pulsator with fuel line last year. No leaking fuel at fpr. I don't think the injectors are leaking as many times as I have looked for leaks or drips. I think it would be a massive fuel injector leak to lose so much pressure so fast ? I'm going with the crazy , crazy ideal that when I take the fuel cap off the fumes are overwhelming, like the gas is being poured in the tank ? thinking new fuel pump and sock in the near future ?
Thread Starter
Instructor
Joined: Sep 2015
Posts: 143
Likes: 25
Hello,
I tried to clamp the lines, but no go. It runs and drives great. I am planning on changing the injectors anyway. Someday. Anything over and above that ? I don't mind changing a fuel pump or even a fpr if I need to.
I tried to clamp the lines, but no go. It runs and drives great. I am planning on changing the injectors anyway. Someday. Anything over and above that ? I don't mind changing a fuel pump or even a fpr if I need to.
Team Owner
Joined: Jul 2004
Posts: 28,463
Likes: 3,288
From: Hartford WI
Anyday you do it, they aren't worth crap. "Runs great" means nothing when you don't have anything to compare it to. Injectors don't go bad suddenly on an "only" basis. They go bad gradually/
Without a proper test, you can change everything you want. You may even get lucky and fix any issues you have. I believe it is called the "shotgun approach" or the "Throw parts at it approach". Both get costly and frustrating but YMMV.
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Team Owner
Joined: Jul 2004
Posts: 28,463
Likes: 3,288
From: Hartford WI
