Fuel Pump
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Joined: Sep 2014
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From: Smithfield VA
Fuel Pump
So who makes the best, most reliable replacement fuel pumps for our cars?
I have had fuel pressure issues with my '92 LT1 almost the entire time I have had it. Right now, it will not maintain 40 PSI on the rail. Car is giving a module 4 code 55 trouble code (not enough fuel pressure under acceleration). Turn on ignition, pressure jumps to 40 PSI, but once the pump stops, immediately drops to around 32 PSI, and within 15 seconds, is down to 10 PSI. There are no external fuel leaks and the hose in the pump assembly is in brand new condition. So I'm thinking the pump is leaking fuel back into the tank (what else could it be?). I am tired of screwing around with cheap parts that don't last. So for you Vette owners that have had fuel pressure issues before and have fixed the problem, what pumps are you using?
BTW, I currently have an AirTex pump, which according to my mechanic friend is pure ****.
I have had fuel pressure issues with my '92 LT1 almost the entire time I have had it. Right now, it will not maintain 40 PSI on the rail. Car is giving a module 4 code 55 trouble code (not enough fuel pressure under acceleration). Turn on ignition, pressure jumps to 40 PSI, but once the pump stops, immediately drops to around 32 PSI, and within 15 seconds, is down to 10 PSI. There are no external fuel leaks and the hose in the pump assembly is in brand new condition. So I'm thinking the pump is leaking fuel back into the tank (what else could it be?). I am tired of screwing around with cheap parts that don't last. So for you Vette owners that have had fuel pressure issues before and have fixed the problem, what pumps are you using?
BTW, I currently have an AirTex pump, which according to my mechanic friend is pure ****.
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Joined: Sep 2014
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From: Smithfield VA
pump has been replaced since I bought the car last Sept. Regulator was just replaced since these problems started. Fuel rail holds 40 psi when pump is running for prime.
Pressure has been checked, from OP-
With engine running, 38 PSI on the rail at idle, pressure drops to around 32 PSI as RPMs increase
Turn on ignition, pressure jumps to 40 PSI, but once the pump stops, immediately drops to around 32 PSI, and within 15 seconds, is down to 10 PSI.
Last edited by 1stVetteFinally; Jul 28, 2015 at 09:19 AM.
Safety Car
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From: Adelaide South Australia
you can test the pressure to see if its going back to the tank by clamping off either the inlet or outlet rubber lines as they come out of the fuel tank, clamp them off just after 'key on -prime the pump'.
Best to get someone to help you do this so you can clamp off quickly before pressure is lost.
Best to get someone to help you do this so you can clamp off quickly before pressure is lost.
Thread Starter
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Joined: Sep 2014
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From: Smithfield VA
you can test the pressure to see if its going back to the tank by clamping off either the inlet or outlet rubber lines as they come out of the fuel tank, clamp them off just after 'key on -prime the pump'.
Best to get someone to help you do this so you can clamp off quickly before pressure is lost.
Best to get someone to help you do this so you can clamp off quickly before pressure is lost.
Thread Starter
Pro
Joined: Sep 2014
Posts: 588
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From: Smithfield VA
edit: just went and checked for gas smell from vacuum line to fpr, no gas smell
Last edited by 1stVetteFinally; Jul 28, 2015 at 09:56 AM.
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The cheak valve on the pump may not be that good most are not but should still keep the pressure up while running maybe just a loose clamp on the rubber hose in the tank. Or the wrong hose.
Last edited by antfarmer2; Jul 28, 2015 at 10:23 AM.
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From: Smithfield VA
BTW, I appreciate the help
Last edited by 1stVetteFinally; Jul 28, 2015 at 10:31 AM.
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From: Smithfield VA
They are soft and bendable. They don't "look" very old tbh. I guess I could use a cloth between the visegrips and hose to make sure they don't get the beginning of a cut
Last edited by 1stVetteFinally; Jul 28, 2015 at 10:38 AM.
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Your "mechanic friend" that was so quick to point out the pump you have as being a piece of **** should understand everything that needs to be done to check for fuel "leak down". If he doesn't well so much maybe for his condemnation of the pump you chose and maybe the "mechanic" tag you hung on him.
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From: Smithfield VA
will do
He was referring to AirTex fuel pumps in general. From what I have read from customer reviews of AirTex pumps, they aren't the best when it comes to reliability.
Cheap part= you get what you pay for
Your "mechanic friend" that was so quick to point out the pump you have as being a piece of **** should understand everything that needs to be done to check for fuel "leak down". If he doesn't well so much maybe for his condemnation of the pump you chose and maybe the "mechanic" tag you hung on him.
Cheap part= you get what you pay for
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Well you've not mentioned the fuel filter condition or the strainer in the tank. Fuel filter can certainly allow full pressure at start up and could certainly diminish at run like you mention, Is the filter mounted maybe backwards? The sock in the tank?
A check valve failure in the pump is certainly a maybe BUT if you purchased local it should be a simple matter of claiming failure. Purchased elsewhere it could be maybe more difficult.
If purchased local what other branding does the store offer? What do they recommend instead of your choice?
A check valve failure in the pump is certainly a maybe BUT if you purchased local it should be a simple matter of claiming failure. Purchased elsewhere it could be maybe more difficult.
If purchased local what other branding does the store offer? What do they recommend instead of your choice?
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Well you've not mentioned the fuel filter condition or the strainer in the tank. Fuel filter can certainly allow full pressure at start up and could certainly diminish at run like you mention, Is the filter mounted maybe backwards? The sock in the tank?
A check valve failure in the pump is certainly a maybe BUT if you purchased local it should be a simple matter of claiming failure. Purchased elsewhere it could be maybe more difficult.
If purchased local what other branding does the store offer? What do they recommend instead of your choice?
A check valve failure in the pump is certainly a maybe BUT if you purchased local it should be a simple matter of claiming failure. Purchased elsewhere it could be maybe more difficult.
If purchased local what other branding does the store offer? What do they recommend instead of your choice?
I just took that for granted that filters were done. 
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I thought you were working on the car not getting it done playing on the puter. 
