Fuel Pressure Issues with LS1 Swap
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Car: 1988 Iroc-Z
Engine: LS1
Transmission: T-56
Axle/Gears: 3.27
Fuel Pressure Issues with LS1 Swap
I'll give yall some background to get up to speed about my swap. Most of these parts were bought back in 08 and weren't used untill a month ago or so.
So I just recently started the car up and adjusted the Fuel pressure regulator W/Return (Keep the stock Fuel tank and installed a Grantelli 255lph Fuel pump) at 58psi. Today i start it up and the fuel pressure is all over the place, varying from 38-43psi and adjusting the screw in doesn't raise the fuel pressure. I hope it isn't the fuel pump biting the dust, now that i think of it maybe I need to replace the Fuel filter? If i have to drop the tank im going to be pissed. Thanks for yalls help in advance..
So I just recently started the car up and adjusted the Fuel pressure regulator W/Return (Keep the stock Fuel tank and installed a Grantelli 255lph Fuel pump) at 58psi. Today i start it up and the fuel pressure is all over the place, varying from 38-43psi and adjusting the screw in doesn't raise the fuel pressure. I hope it isn't the fuel pump biting the dust, now that i think of it maybe I need to replace the Fuel filter? If i have to drop the tank im going to be pissed. Thanks for yalls help in advance..
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Car: 89 Camaro RS
Engine: LM7
Transmission: T56
Axle/Gears: 3.42
Re: Fuel Pressure Issues with LS1 Swap
The first Walbro 255 I had lasted about for about an hours worth of run time before the fuel pressure dropped to around 33lbs. I think the Grantelli 255 and the Walbro 255 are the exact same pumps. I got my second pump from Racetronix and haven't had a problem with it. From what I’ve read some vendors have a cheaper less reliable version of the pump.
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Car: 1988 Iroc-Z
Engine: LS1
Transmission: T-56
Axle/Gears: 3.27
Re: Fuel Pressure Issues with LS1 Swap
The first Walbro 255 I had lasted about for about an hours worth of run time before the fuel pressure dropped to around 33lbs. I think the Grantelli 255 and the Walbro 255 are the exact same pumps. I got my second pump from Racetronix and haven't had a problem with it. From what I’ve read some vendors have a cheaper less reliable version of the pump.
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Car: 1988 Iroc-Z
Engine: LS1
Transmission: T-56
Axle/Gears: 3.27
Re: Fuel Pressure Issues with LS1 Swap
You know im really glad i have an External Fuel pressure regulator, how would I of seen this coming ? I ran it alittle bit last night and it would jump up to 58psi when i started it then slower but surely as i revved it up bleed off the pressure till it got around 38-42, then it started flucatuating from 20-40psi.
I did swap out the 30# injectors for the stock ones and that made it idle a ton better on a stock tune.
I did swap out the 30# injectors for the stock ones and that made it idle a ton better on a stock tune.
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Car: 1988 Iroc-Z
Engine: LS1
Transmission: T-56
Axle/Gears: 3.27
Re: Fuel Pressure Issues with LS1 Swap
I just thought of something else, I left all the stock TPI Fuel lines/EVAP vent line in place. I capped the EVAP Vent line, would that be causing this problem ?
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#8
Re: Fuel Pressure Issues with LS1 Swap
The first Walbro 255 I had lasted about for about an hours worth of run time before the fuel pressure dropped to around 33lbs. I think the Grantelli 255 and the Walbro 255 are the exact same pumps. I got my second pump from Racetronix and haven't had a problem with it. From what I’ve read some vendors have a cheaper less reliable version of the pump.
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Car: 1989 IROC-Z, 1979 Malibu Classic
Engine: LSx 5.3
Transmission: MN12 6-speed, 4L60E
Axle/Gears: 4th gen 3.42
Re: Fuel Pressure Issues with LS1 Swap
Just had my Walbro 255 pump take a **** on me about two weeks ago. I had only been driving the car for about a month and it went out on me while I was crossing a bridge. I can hear my pump run but it does not produce any pressure at all. I left my vent line open because under WOT the pump can produce a vacuum in the tank, and when the car is off it keeps the tank from pressurizing.
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Car: 1988 Iroc-Z
Engine: LS1
Transmission: T-56
Axle/Gears: 3.27
Re: Fuel Pressure Issues with LS1 Swap
Just had my Walbro 255 pump take a **** on me about two weeks ago. I had only been driving the car for about a month and it went out on me while I was crossing a bridge. I can hear my pump run but it does not produce any pressure at all. I left my vent line open because under WOT the pump can produce a vacuum in the tank, and when the car is off it keeps the tank from pressurizing.
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Car: 1989 IROC-Z, 1979 Malibu Classic
Engine: LSx 5.3
Transmission: MN12 6-speed, 4L60E
Axle/Gears: 4th gen 3.42
Re: Fuel Pressure Issues with LS1 Swap
Bought mine from Jegs, it was an edelbrock drop-in but the pump had "Walbro" stamped on it. Good thing about buying from Jegs, I have 3 years to turn this pump in as a defective unit and they'll send me a new one free of charge. Some of us must just be getting a bad batch of pumps, kinda sucks because I hate taking my tank down.
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Re: Fuel Pressure Issues with LS1 Swap
having fuel pressure issues myself did the corvette filter and capped my vent to the purge canister going to swap filter first then check voltage to pump gosh i hate dropping my tank but we e gotta do it
#13
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Car: 1982 Z28
Engine: LS1
Transmission: T56
Re: Fuel Pressure Issues with LS1 Swap
So I just recently started the car up and adjusted the Fuel pressure regulator W/Return (Keep the stock Fuel tank and installed a Grantelli 255lph Fuel pump) at 58psi. Today i start it up and the fuel pressure is all over the place, varying from 38-43psi and adjusting the screw in doesn't raise the fuel pressure.
#14
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Car: 1988 Iroc-Z
Engine: LS1
Transmission: T-56
Axle/Gears: 3.27
Re: Fuel Pressure Issues with LS1 Swap
Don't believe thats needed, only for boosted aplications. Of course I maybe wrong.
I uploaded a short video of what its doing on youtube. Please excuse the crappy HTC EVO Video clip quality.
http://www.youtube.com/watch?v=A6iZpdFgnJ8
I uploaded a short video of what its doing on youtube. Please excuse the crappy HTC EVO Video clip quality.
http://www.youtube.com/watch?v=A6iZpdFgnJ8
#15
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Car: 1988 Iroc-Z
Engine: LS1
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Axle/Gears: 3.27
Re: Fuel Pressure Issues with LS1 Swap
So i dropped the fuel tank over the weekend, I didn't visible see any signs of failure. Of course the pump could be going bad internally. The one thing I noticed after the fact of install this pump is the wiring harness that connects from the factory harness to the pump is 18gauge wire, WTF. Why would you go from 14 to 18 guage wire ? When i get the new racetronixs pump im going to soilder in some 14awg wire if that harness doesn't have it.
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Car: 1988 Iroc-Z
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Re: Fuel Pressure Issues with LS1 Swap
Just ordered my Fuel pump kit from racetronixs, going to have to wait till Dec 1st to get my pump. I miss jegs shipping =(
#18
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Car: 1982 Z28
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Re: Fuel Pressure Issues with LS1 Swap
I didn't need the extra copper on my '82, just have good clean grounds and positive crimps & solder on my harness connector pins.
The GSS340 gerotor pump uses less amps making 58psi than the factory Delco TPI turbine pump at 43psi, so unless your rear harness is trashed there's not much reason to upgrade the wiring IMHO.
The GSS340 gerotor pump uses less amps making 58psi than the factory Delco TPI turbine pump at 43psi, so unless your rear harness is trashed there's not much reason to upgrade the wiring IMHO.
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Car: 1988 Iroc-Z
Engine: LS1
Transmission: T-56
Axle/Gears: 3.27
Re: Fuel Pressure Issues with LS1 Swap
I didn't need the extra copper on my '82, just have good clean grounds and positive crimps & solder on my harness connector pins.
The GSS340 gerotor pump uses less amps making 58psi than the factory Delco TPI turbine pump at 43psi, so unless your rear harness is trashed there's not much reason to upgrade the wiring IMHO.
The GSS340 gerotor pump uses less amps making 58psi than the factory Delco TPI turbine pump at 43psi, so unless your rear harness is trashed there's not much reason to upgrade the wiring IMHO.
Good news to hear, the Fuel pump i ordered is part number-GSS340M so its a older model. The pump i just pulled out was the F20000169.
My rear harness is in perfect shape visually, along we all know how copper stranded wire gets corroded after time. I do however find it strange that they go from 14awg wire to 18awg with the fuel pump harness in the gas tank.
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Car: 82 Berlinetta/57 Bel Air
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I haven't had any problems with the smaller wire with either my Walbro 255, or a stock 4th gen tank/pump.
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Re: Fuel Pressure Issues with LS1 Swap
Here are some pictures of the new pump I installed last night, man what a difference between the two. The Racetronixs pump is almost 2x heaver than the Granettli walbro pump and check out that wiring, I knew i was on to something when i saw the gauge difference.
The First picture is the Granettli pump, next picture is the difference between the two wiring harnesses and the final picture is the new Racetronix walbro pump. Enjoy
The First picture is the Granettli pump, next picture is the difference between the two wiring harnesses and the final picture is the new Racetronix walbro pump. Enjoy
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Re: Fuel Pressure Issues with LS1 Swap
Just checking in, The fuel pump was the problem. It not moving a bit now woo hooo !!!
#27
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Re: Fuel Pressure Issues with LS1 Swap
guys u may want to drop ur tank even before ordering a pump mu rubber connection hose was the prob! i did however replace the pump while i was in there! just sayin may be a less expensive alternative i could have only replaced the hose for about 2 bucks but i had all the labor invested!
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