well, i thought i was going to get to fire up my car this afternoon but no such luck. it was getting dark fast this evening, and by the time i fixed all my leaks (one coolant leak due to a faulty sensor on the cyl. head, and one fuel leak due to a fitting on the fuel rail) it was time to call it quits. but before i went in, what i did notice was that when i would turn the key on to energize the fuel pump, the pressure would go up to ~50 psi but then drop back down immediately. i had to turn the key on again to get the pressure up. but it would drop back down again (to zero). i'd like to rule out the leaky injector theory since they are all brand new 83 lb injectors. that leaves the fuel pump itself or the regulator, right? for now, i'm running a Bosch fuel pump only good to 450 hp which i am scrapping anyway. just haven't had time to order a nice new pump (probably go with an SX). i figured since i'd be breaking in the engine with minimal boost, i wouldn't need the new pump yet. the regulator is an adjustable piece that came with my TPIS miniram. does anyone have any suggestions?

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Jeff
99 T/A WS6 A4, RKSport lid & free EGR mod
88 GTA twin turbo 358, forged crank, forged H-beam rods, Wiseco reverse dome pistons, Dart Sportsman II 72cc heads, Comp Cams custom grind blower cam (.560/.586 lift, 232/236 duration), 1.6 roller rockers, TPIS mini ram intake manifold w/ Accel 58mm TB, 83 lb injectors, Accel DFI computer with variable injector controller, 2 Garrett T04B "hair dryers" with dual Garrett wastegates, TH400 tranny with BTE transbrake and Art Carr custom converter, F*rd 9 inch rear w/ 3.50 gears, and more...

 

Go back through all of your fuel line connections. Make sure any o-ring seals are sealing good. Check your rails.

Do you smell gas?

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-86 IROC
Vortech stuffed EFI 406 in progress
-=ICON Motorsports=-

 

I had the same problem with my car. It would run fine, but pressure bled off immediately, and I had no leaks of any kind. Replacing the fuel pump fixed the problem. I guess the fuel pump has an anti drain-back valve that tends to not be too reliable.

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The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

 

i appreciate everyone's input. i don't think i will have a problem starting it. the pressure stays up while cranking the car over, but just drains back when you stop. the fuel pump is going to be replaced anyway within the next couple of weeks. i'm considering using a single SX pump... of course i'm open to more suggestions. i don't want to run 2 pumps.

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Jeff
99 T/A WS6 A4, RKSport lid & free EGR mod
88 GTA twin turbo 358, forged crank, forged H-beam rods, Wiseco reverse dome pistons, Dart Sportsman II 72cc heads, Comp Cams custom grind blower cam (.560/.586 lift, 232/236 duration), 1.6 roller rockers, TPIS mini ram intake manifold w/ Accel 58mm TB, 83 lb injectors, Accel DFI computer with variable injector controller, 2 Garrett T04B "hair dryers" with dual Garrett wastegates, TH400 tranny with BTE transbrake and Art Carr custom converter, F*rd 9 inch rear w/ 3.50 gears, and more...

 

TT358, when you order that SX pump you need to also order SX pn. 00501. This is a -10 full flow check valve that you put in line to keep all the fuel from draining back to the tank. You could also just use it with your current pump to take care of the problem to.

 

thanks JeffT! i should be ordering my pump this week...

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Jeff
99 T/A WS6 A4, RKSport lid & free EGR mod
88 GTA twin turbo 358, forged crank, forged H-beam rods, Wiseco reverse dome pistons, Dart Sportsman II 72cc heads, Comp Cams custom grind blower cam (.560/.586 lift, 232/236 duration), 1.6 roller rockers, TPIS mini ram intake manifold w/ Accel 58mm TB, 83 lb injectors, Accel DFI computer with variable injector controller, 2 Garrett T04B "hair dryers" with dual Garrett wastegates, TH400 tranny with BTE transbrake and Art Carr custom converter, F*rd 9 inch rear w/ 3.50 gears, and more...

 

Not to insult you, but doesn't the ECM shut off the fuel pump after about 2 seconds if you don't start the car?

Pressure for a few seconds when you turn on the key, pressure during cranking, right?

Just the obvious.

John

 

You should have some rest pressure. any where from 25psi and up. If you turn the key off and it goes to 0 then, send 12volts to the fuel pump test wire, while the pump is running clamp off the return hose with pliers( or hose clamp offs) and then turn pump off. If pressure stays up then it is the regulator, if the pressure drops to 0psi then send 12volts to the pump again now clamp off the fuel line(feed line) with the return still clamp closed. with both lines clamped closed with the pump running(don't let it run for very long with the return or feed line clamped off) When you have both clamped closed then turn off pump, if the pressure still drops(to 0 psi) then you have a leak somewhere on the lines OR a leaking injector. If the pressure stays high then the check ball in the fuel pump is bad and the pump needs to be replaced.
I am not sure if the HIGH PERFORMANCE Pumps(SX , Paxton etc... have these check ***** in to keep rest pressure, they may drop to 0psi )

I hope this helps
Jeff

 

812MANY, no insult taken. but i was actually referring to pressure retaining in the lines not the fuel pump running. on my old 95 LT1 that i used to have, it would hold fuel pressure even when you turn the key off. i guess that's what i was used to seeing, so i was a little confused working on my third gen with aftermarket pump.

as it turns out, there was no problem. the fuel pump i have just doesn't hold pressure with the key off.

i actually got it fired up today, but ran into an electrical problem. hopefully i can get a relay and be back in business soon!!!

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Jeff
99 T/A WS6 A4, RKSport lid & free EGR mod
88 GTA twin turbo 358, forged crank, forged H-beam rods, Wiseco reverse dome pistons, Dart Sportsman II 72cc heads, Comp Cams custom grind blower cam (.560/.586 lift, 232/236 duration), 1.6 roller rockers, TPIS mini ram intake manifold w/ Accel 58mm TB, 83 lb injectors, Accel DFI computer with variable injector controller, 2 Garrett T04B "hair dryers" with dual Garrett wastegates, TH400 tranny with BTE transbrake and Art Carr custom converter, F*rd 9 inch rear w/ 3.50 gears, and more...