fuel pressure drops after the prime
fuel pressure drops after the prime when i turn the key on my fuel pressure goes to 44psi then it drops down to 0. i know that not right..what could cause this??
another thing my car runs good until it hits 5000-6200 after 5g it starts to break up and miss.
if i try using nitrous threw 1st and 2nd it breaks up to bad in 2nd that i cant even use it..any help is appreciated thanks
another thing my car runs good until it hits 5000-6200 after 5g it starts to break up and miss.
if i try using nitrous threw 1st and 2nd it breaks up to bad in 2nd that i cant even use it..any help is appreciated thanks
Teching In
Joined: Jan 2005
Posts: 48
Likes: 0
From: Warren, MI
the fuel pressure dropping after prime sounds like the check valve in the fuel pump is bad. Once it primes the fuel just runs back into the tank. The chack valve is suppose to stop that from happening.
Doube check your injectors that they were installed right.
What are you using to measure the fuel pressure?
Did the problems on the nitrous just start occurring?
What is the status on your ignition? (plugs, wires, coil, opti)
What are you using to measure the fuel pressure?
Did the problems on the nitrous just start occurring?
What is the status on your ignition? (plugs, wires, coil, opti)
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Teching In
Joined: Jul 2005
Posts: 32
Likes: 0
Originally Posted by Bad Dad
What kind of AFPR are you using? With Areomotive this is a normal condition.
Got rid of that and just got another brand... no leakdown and no dribbling gas...
Just another idea.... so check the vacuume line on your afpr and see if there is gas in there.... if so that is a problem
good luck
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I had the same thing happen with my racetronix pump, there was a small hole in the teflon line that runs from the pump to the metal line going out of ther tank. It was a bitch to find, I found it by taking the pump out of the tank and pressurizing it on the bench.
yes it is an aeromotive fpr i didnt even think to replace it cause its new, it was on the car when i got it. i have changed injectors and it still lost pressure, i changed the pump and still lost pressure,, but i didnt think to change that. thanks everyone!! thats what ill be checking tonight 
Launching!
Joined: Dec 2004
Posts: 284
Likes: 1
From: Hebron, Oh
Aeromotive regulators bleed down a bit. I have one and it bleeds down since new. No fuel coming from the vacuum nipple. I thought something was wrong with it, but then I read that people were having the same issue. One guy supposedly contacted Aeromotive and was told that they bleed down to prevent fuel heat soak in the rail or something along those lines. I left mine on and have had no issues. Also running a walbro pump and svo injectors. I have my regulator set at 43.5 psi with line off, and it will bleed down to about half that. It will then hold pressure. I've run it this way the last year since I found the info and have had no problems with starting or such.
TECH Fanatic
Joined: May 2006
Posts: 1,230
Likes: 0
From: Lexington,MO
Originally Posted by rkinney
Aeromotive regulators bleed down a bit. I have one and it bleeds down since new. No fuel coming from the vacuum nipple. I thought something was wrong with it, but then I read that people were having the same issue. One guy supposedly contacted Aeromotive and was told that they bleed down to prevent fuel heat soak in the rail or something along those lines. I left mine on and have had no issues. Also running a walbro pump and svo injectors. I have my regulator set at 43.5 psi with line off, and it will bleed down to about half that. It will then hold pressure. I've run it this way the last year since I found the info and have had no problems with starting or such.
Joined: Mar 2002
Posts: 2,032
Likes: 26
From: A Racetronix dealer near you...
Originally Posted by Subliminal Hit
walbro pumps don't have a check valve, mine loses pressure as soon as I shut the car off. Its normal.
http://www.racetronix.com/images/Fue...ump_head-a.jpg
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Manufacturer / Distributor of Automotive Fuel Systems, Components & Electronics
Please support a Racetronix dealer near you for personalized service.
>WEB SITE<
my fuel pump sending unit has been sticking at a 1/4 tank so i was gonna drop the tank down and see why. should i switch the pump to one that has a check valve or just leave it alone. only reason i got the pump was cause it was a ebay special
