Fuel Pressure Acting Goofy.
06-23-2006, 11:17 AM
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The car is all up and running and driving fine now.. but i have a weird problem every so often. usually when im lower on fuel, about 1 gal. left, but it shouldnt be happening..
car drives perfectly normal 90% of the time, under boost, and reg. driving..
sometimes i will go to boost, and the car will run lean as soon as boost starts building.. hmm lemme guess, not enough fuel... o wait, not enough fuel pressure.. i get out of car, look at my fuel pressure gauge on my aeromotive fpr, its at like 25psi with vac attached, roughly 33psi or so un attached.
i had it set at 40psi idle fuel pressure with the vac. not attached. obviously with it attached it dropped to around 33-35ish.
i am stumped at this point. why would the fuel pressure just drop? it only happens sometimes, and then is fine at other times..
my fuel system goes like this, just so everyone knows my fuel setup
255lph walbro fuel pump >>> stock system >>> Ts-into both of my rails >>> boost rail has other side blocked off >>> stock rail goes thru to -6AN line to Aeromotive FPR >>> return line goes back like stock >>> fuel gauge is right on the aeromotive..
car drives perfectly normal 90% of the time, under boost, and reg. driving..
sometimes i will go to boost, and the car will run lean as soon as boost starts building.. hmm lemme guess, not enough fuel... o wait, not enough fuel pressure.. i get out of car, look at my fuel pressure gauge on my aeromotive fpr, its at like 25psi with vac attached, roughly 33psi or so un attached.
i had it set at 40psi idle fuel pressure with the vac. not attached. obviously with it attached it dropped to around 33-35ish.
i am stumped at this point. why would the fuel pressure just drop? it only happens sometimes, and then is fine at other times..
my fuel system goes like this, just so everyone knows my fuel setup
255lph walbro fuel pump >>> stock system >>> Ts-into both of my rails >>> boost rail has other side blocked off >>> stock rail goes thru to -6AN line to Aeromotive FPR >>> return line goes back like stock >>> fuel gauge is right on the aeromotive..
06-23-2006, 10:59 PM
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QUOTE
The car is all up and running and driving fine now.. but i have a weird problem every so often. usually when im lower on fuel, about 1 gal. left, but it shouldnt be happening
you have the solution right in front of you..
g force pushes the fuel back ward, fue lbeen low pump pick up isnt' covered by fuel anymore. .so. .fuel pump try to pump but can't
put a gauge that you can see while driving and each time the car is low on fuel and you run it hard fuel pressure wil ldrop
wich fuel pump pick up did you use?
06-23-2006, 11:26 PM
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Vehicle: 1998 Tiburon
I have the same problem man.
When I get lower than a 1/4 tank on the gas meter my car drives like something from the 50s lol.
Ive noticed that the tibs gauge isnt very accurate when the tank is getting empty and falls off real quick down there, so I just attributed it to not enough gas reacing the engine OR the ECU being programmed to drive lame to preserve fuel so you dont run out.
When I get lower than a 1/4 tank on the gas meter my car drives like something from the 50s lol.
Ive noticed that the tibs gauge isnt very accurate when the tank is getting empty and falls off real quick down there, so I just attributed it to not enough gas reacing the engine OR the ECU being programmed to drive lame to preserve fuel so you dont run out.
06-24-2006, 01:43 AM
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QUOTE (Denisst99 @ Jun 23 2006, 11:59 PM)
you have the solution right in front of you..
g force pushes the fuel back ward, fue lbeen low pump pick up isnt' covered by fuel anymore. .so. .fuel pump try to pump but can't
put a gauge that you can see while driving and each time the car is low on fuel and you run it hard fuel pressure wil ldrop
g force pushes the fuel back ward, fue lbeen low pump pick up isnt' covered by fuel anymore. .so. .fuel pump try to pump but can't
put a gauge that you can see while driving and each time the car is low on fuel and you run it hard fuel pressure wil ldrop
right-o!!!
just make sure you have a couple more gallons in there when you are boosting lots
06-26-2006, 06:13 AM
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walbro 255lph pump
anyway, yesterday i had the same problem, just as i started to spool, and boost a lil ran at like 17-18:1 which is not good at all. obviously i backed off at that point. sometimes its perfectly fine.. i boosted throughout 4th gear on the highway, and it was running like 11.8:1 which is what it should be at.. and sometimes when i was having the problem my idle fuel psi wasnt even down..
ill check the wiring today, i had the problem before a lil bit, but my ecu kinda came unplugged, and i had problem with ignition (was gorunding out, lol)
anyway, yesterday i had the same problem, just as i started to spool, and boost a lil ran at like 17-18:1 which is not good at all. obviously i backed off at that point. sometimes its perfectly fine.. i boosted throughout 4th gear on the highway, and it was running like 11.8:1 which is what it should be at.. and sometimes when i was having the problem my idle fuel psi wasnt even down..
ill check the wiring today, i had the problem before a lil bit, but my ecu kinda came unplugged, and i had problem with ignition (was gorunding out, lol)
06-26-2006, 06:26 AM
#7
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You could always sump the tank and install an external pump. Then you'll definately be able to pick up most of that last gallon. fing02.gif