Fuel Pressure Guru's I need Help
Nov 8, 2009 | 01:30 AM
#11
This is incorrect.
On a 99-03 return system, you should have 55-62 PSI of pressure with the key on, engine off. After the pump stops priming, the pressure should drop no more than 5 PSI over the next 10 minutes if you don't start the engine. With the engine idling and at operating temperature, the normal fuel pressure should be 3-10 PSI lower than the pressure with the key on, engine off. When driving around the pressure will vary depending on how much manifold vacuum you have at that point. At WOT, the pressure should be 4 bar (58 PSI). To verify the FP regulator is working properly, remove the vacuum line to it and FP should go up to 58.
On a 99-03 return system, you should have 55-62 PSI of pressure with the key on, engine off. After the pump stops priming, the pressure should drop no more than 5 PSI over the next 10 minutes if you don't start the engine. With the engine idling and at operating temperature, the normal fuel pressure should be 3-10 PSI lower than the pressure with the key on, engine off. When driving around the pressure will vary depending on how much manifold vacuum you have at that point. At WOT, the pressure should be 4 bar (58 PSI). To verify the FP regulator is working properly, remove the vacuum line to it and FP should go up to 58.
if you say so!!!
then tell me why on my 99 and my 01 the fuel pressure stays at 58 (99) 60 (01) even at idle and at WOT.. oh yeah the 99 the fuel regulator is on the fuel rail and the 01 its an external. and on the 99 i loose 7 PSI with key on engine off.. settling out at 53 PSI.. and the 01 i loose 3 psi !! with key on and engine is off yes and after the fuel pump shuts off!!!
i think i would rather have my setup than yours if yours is falling OFF!!!
. Will update soon
Nov 8, 2009 | 06:32 PM
#17
if you say so!!!
then tell me why on my 99 and my 01 the fuel pressure stays at 58 (99) 60 (01) even at idle and at WOT.. oh yeah the 99 the fuel regulator is on the fuel rail and the 01 its an external. and on the 99 i loose 7 PSI with key on engine off.. settling out at 53 PSI.. and the 01 i loose 3 psi !! with key on and engine is off yes and after the fuel pump shuts off!!!
i think i would rather have my setup than yours if yours is falling OFF!!!
then tell me why on my 99 and my 01 the fuel pressure stays at 58 (99) 60 (01) even at idle and at WOT.. oh yeah the 99 the fuel regulator is on the fuel rail and the 01 its an external. and on the 99 i loose 7 PSI with key on engine off.. settling out at 53 PSI.. and the 01 i loose 3 psi !! with key on and engine is off yes and after the fuel pump shuts off!!!
i think i would rather have my setup than yours if yours is falling OFF!!!
Original poster, 43psi is a sign of a pump going bad or clogged filter. FPR's don't usually go bad (cheap to check them though(replace)). If you have touched any of those items once before then they are suspect for failure. Example being I bet 30% of people who touch or change their FPR have issues because it didn't seat correctly.
Nov 8, 2009 | 07:10 PM
#18
not sure about the specs.
had my 00 from day one.
fuel pressure @ idol 42
crusing around 45
wot 50 - 51
since i first got it, changed out the regulator 3 times and the fuel pump 1 time, fuel filter is changed on every 5th oil change.
numbers have never changed when a new part was installed.
took the lines off my FMU for the supercharger and put them on a regulator.
set the pressure to 65 psi.
now, idol 55
crusing around 60
wot 65.
i never understood how you guys had such high fuel pressure on models below and above mine.
had my 00 from day one.
fuel pressure @ idol 42
crusing around 45
wot 50 - 51
since i first got it, changed out the regulator 3 times and the fuel pump 1 time, fuel filter is changed on every 5th oil change.
numbers have never changed when a new part was installed.
took the lines off my FMU for the supercharger and put them on a regulator.
set the pressure to 65 psi.
now, idol 55
crusing around 60
wot 65.
i never understood how you guys had such high fuel pressure on models below and above mine.
Nov 8, 2009 | 07:18 PM
#19
Maybe the vacuum line isn't hooked up on yours, or clogged, or something. I know you are okay with your setup and have no complaints, but it really shouldn't stay constant at 58#'s from idle to WOT. Different atmospheres will net different results. Different engine/cam setups, vacuum, blah blah and so on. I (2000 truck) idle at 53 and cruise at 55 and get 58 before I go into boost (no vacuum). At full boost I see 65#'s +. It wouldn't matter if you had the largest pump in the world in your tank or inline, the FPR will send back to the tank what it doesn't want. At idle that will be approximately anything over 52-55psi.
Original poster, 43psi is a sign of a pump going bad or clogged filter. FPR's don't usually go bad (cheap to check them though(replace)). If you have touched any of those items once before then they are suspect for failure. Example being I bet 30% of people who touch or change their FPR have issues because it didn't seat correctly.
Original poster, 43psi is a sign of a pump going bad or clogged filter. FPR's don't usually go bad (cheap to check them though(replace)). If you have touched any of those items once before then they are suspect for failure. Example being I bet 30% of people who touch or change their FPR have issues because it didn't seat correctly.
thanks for the explanation dew, what may be the downfalls if it does stay constant, i mean i hadnt had any in a couple of years or so, just wondering even if there is any.. but youre right my vac lines arent hooked up..
