fuel pressure problem new pump
fuel pressure problem new pump i have a newly rebuit 95 lt1 355 le2 cam and new walbro 255 kit from racetronix when i first fired it up it ran great for a few days now i get an occsonal stumble and recently the car doesnt always want to start up on the first try. hooked a fuel pressure gage up and i have 41-42psi at idle but when you hit the throddle at all the pressure drops to 38-40psi. going to change the fuel filter tomarrow as a startany other sugestions just kind of wierd this came about all of a sudden. any suggestions would help
ok changed the filter vacaum hooked up
key forward prime 38psi steady for at least 10min no bleed off
idle 42-43psi now a little improvement
under any throddle 40psi steady
now with vacaum unhooked
prime still 38 psi
idle 43-45 psi
under throddle 43psi steady
after car shut off holds 30psi steady no bleed off
does this mean my next step is regulator? or do these psis seem right?
also my gas gage after install is way off like showing at least a 1/4 tank above what it should.
what do i need to check next would like to get this straightened out
also is it safe to run around with vacaum unhooked from regulator to keep psi up in the 43 range instead of 40 for a while?
key forward prime 38psi steady for at least 10min no bleed off
idle 42-43psi now a little improvement
under any throddle 40psi steady
now with vacaum unhooked
prime still 38 psi
idle 43-45 psi
under throddle 43psi steady
after car shut off holds 30psi steady no bleed off
does this mean my next step is regulator? or do these psis seem right?
also my gas gage after install is way off like showing at least a 1/4 tank above what it should.
what do i need to check next would like to get this straightened out
also is it safe to run around with vacaum unhooked from regulator to keep psi up in the 43 range instead of 40 for a while?
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Verdad Gallardo ok heres the latest car currently really hard to start needs throddle pushed to get it to even try at prime it goes to 45psi till pump shuts off if i pull the injector fuses motor fires right up till out of gas
leaky injector? any way to test this without pulling fuel rail as i have bosch 3 with those damn clip on thingys at the bottom that like to fall down the intake port if the oring pushs against it to much.
leaky injector? any way to test this without pulling fuel rail as i have bosch 3 with those damn clip on thingys at the bottom that like to fall down the intake port if the oring pushs against it to much.
ok car is leaking down 10-15 psi immediately after pump stops running hard to start doesnt hold right pressure as going down the road vacum unhooked only keeps pressure around 43 steady if i get car started its running rich and choking its self
leaking injectors???????
leaking injectors???????
ok ill try that tonight/tomarrow in my mind something leaking down most likely injector its running pig rich and chokes on its own fuel once i finily get it fired up using the throddle open1/2 to 3/4
pressure leaks down after pump quits not leaking injectors checked today what should i be looking for? will be replacing regulator tomarrow its running pig rich to a point its hard to keep car running
Rich condition would not be caused by pressure bleed off. Only if the system was over pressure or leaking injectors or an internal leak in the regulator. Starting to sound like ignition or tune related. Who did the tune?
If you are losing pressure and it's not an injector check the hose that runs from the pump to hard line coming out of the tank. I had the same symptoms and there was a pinhole leak in that hose. I found it by pressurizing the line with the pump out of the tank.
TECH Enthusiast
Joined: Mar 2009
Posts: 680
Likes: 8
From: Clearwater
definitely check this. had the same problem when i changed out the 13 year old pump.