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Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

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Old May 25, 2016 | 02:33 PM
  #1  
amfornal's Avatar
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From: Lenexa, KS
Car: 1989 IROC Z L98 G92
Engine: 5.7
Transmission: 700R4
Axle/Gears: 3.27 G92
Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

I have a 1989 L98 Tpi Camaro Iroc-z. After driving it around and running fantastically!!!, all of a sudden every once in a while car would stall and sputter then continue to run just fine. Later that same day would stall and sputter a little more frequently. I thought a TPS problem and after wiggling the wires at the sensor car ran fine for some time. Later that day stalling and sputtering came back with a little more frequency, but still intermittently. Then, after turning the car off, it will not start at all.I Happend to be in front of a service station and they checked the fuel pressure at the the rail and had no pressure. Sprayed starter fluid and cranked motor and it started fine. Towed car home and suspecting Fuel Pump, it was replaced. No start and still no fuel pressure at rail. I mean none!! I have had all new fuel injectors replaced with in the last 8 months, new distributor, plugs, wires and fuel filter. Since car is 26 years old I have now went ahead and replaced IAC, TPS, MAF sensor. I have done a search on this and there seems to be all kinds of similar scenarios, but not like this one to where car ran FANTASTIC!!!! and then went to crap all of a sudden. This looks to me to be some type of simple electerical issue, but can't seem to norrow it doen. Any help would greatly be appreciated. Thanks, amfornal
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Old May 25, 2016 | 03:07 PM
  #2  
Billgluckman's Avatar
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Re: Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

Originally Posted by amfornal
I have a 1989 L98 Tpi Camaro Iroc-z. After driving it around and running fantastically!!!, all of a sudden every once in a while car would stall and sputter then continue to run just fine. Later that same day would stall and sputter a little more frequently. I thought a TPS problem and after wiggling the wires at the sensor car ran fine for some time. Later that day stalling and sputtering came back with a little more frequency, but still intermittently. Then, after turning the car off, it will not start at all.I Happend to be in front of a service station and they checked the fuel pressure at the the rail and had no pressure. Sprayed starter fluid and cranked motor and it started fine. Towed car home and suspecting Fuel Pump, it was replaced. No start and still no fuel pressure at rail. I mean none!! I have had all new fuel injectors replaced with in the last 8 months, new distributor, plugs, wires and fuel filter. Since car is 26 years old I have now went ahead and replaced IAC, TPS, MAF sensor. I have done a search on this and there seems to be all kinds of similar scenarios, but not like this one to where car ran FANTASTIC!!!! and then went to crap all of a sudden. This looks to me to be some type of simple electerical issue, but can't seem to norrow it doen. Any help would greatly be appreciated. Thanks, amfornal
Can you hear the fuel pump coming on?
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Old May 25, 2016 | 03:19 PM
  #3  
Bob88GTA's Avatar
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From: Huntsville AL
Car: 88GTA
Engine: 5.7TPI
Transmission: Auto
Axle/Gears: 3.27
Re: Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

KOEO 2 second prime heard? FP Relay? Oil Pressure switch? Are you sure you're getting the pressure gauge hose all the way on the Schrader Valve? I checked mine and found I had to really make sure it was all the way on before it read. JMO, HTH's.
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Old May 25, 2016 | 06:40 PM
  #4  
amfornal's Avatar
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Joined: May 2015
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From: Lenexa, KS
Car: 1989 IROC Z L98 G92
Engine: 5.7
Transmission: 700R4
Axle/Gears: 3.27 G92
Re: Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

I can hear the pump come on with the turn of the key. Also, I hear the click of the FP relay. Just in case i swapped relays with the one next to it just to make sure..... KOEO 2nd prime????
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Old May 25, 2016 | 07:26 PM
  #5  
BlueIROC87's Avatar
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From: Plano, Texas
Re: Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

How I fixed my no fuel issue:

Perform a visual check of the fuel filter. Is it installed in the correct direction with relation to fuel flow?

Verify you have fuel making it up to to the driver's side engine bay by unbolting the black rubber fuel line coming from the tank. It is the larger of the two black rubber lines (fuel supply to engine). They are located along the frame rail near the steering shaft. Have a rag handy to capture any existing fuel in the line when you loosen it. Place the end in a container, don't start car, simply turn key to the on position. Allow fuel pump to run it's 2 seconds. Any output? if not, turn key off, wait 10 seconds and try again. If no output, move on.

Disconnect the vacuum line from your fuel pressure regulator. Cycle the key a few times similar to the step above. Any fuel leaking from the vacuum port on the regulator? If yes, replace.

Verify the fuel pump is wired correctly. It can run in reverse if wired backwards resulting in plenty of sound but zero output.

If present, verify the pulsator device between the fuel pump and the steel supply line inside the tank in't leaking.

Good luck!
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Old May 26, 2016 | 08:12 AM
  #6  
amfornal's Avatar
Thread Starter
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Joined: May 2015
Posts: 91
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From: Lenexa, KS
Car: 1989 IROC Z L98 G92
Engine: 5.7
Transmission: 700R4
Axle/Gears: 3.27 G92
Re: Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

While I wouldn't have cut out an access hole to the fuel pump, one of the previous owners of this car did. So, taking full advantage of the hole I pulled the fuel pump back out again. With all 4 lines open leading into the fuel tank, I turned the key and heard the pump run but NOTHING coming out of the line(s). So now I am at either the new fuel pump is bad also or the pulsator is massively leaking out.... I did notice when I put the fuel pump in that the pulsator was hard to pull off but VERY easy to slide back on. Next question would be, do I replace the pulsator or just put in a fuel line?
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Old May 30, 2016 | 04:33 PM
  #7  
BlueIROC87's Avatar
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From: Plano, Texas
Re: Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

Based on your feedback, sounds like the two wires connecting to the fuel pump are wired backwards.

Since your car was modified for easy access (mine was too) , just pull the sending unit/fuel pump assembly out one more time, and swap the short wires coming off the fuel pump.

Perform the same output test you mentioned in your earlier post.

At this point in the troubleshooting process, don't worry about the pulsator unless.

1. After swapping pump power wires, you test and see fuel leaking out of it.
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Old Jun 3, 2020 | 02:30 AM
  #8  
mnorton's Avatar
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Joined: May 2002
Posts: 845
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From: Northern California, Redding
Car: Red 1987 IROC Convertible
Engine: 305 LB9 TPI
Transmission: T5 5-Speed
Axle/Gears: 9-Bolt 3.45
Re: Help!! Zero fuel pressure at fuel rail 5.7 TPI even after new fuel pump.

A reply to an old post: The same happened to my car. I too replaced the fuel pump, but still had zero fuel pressure at the fuel rail. As it turns out, the fuel rail is plugged up with what I believe is aluminum oxide, or aluminum rust. The crappy fuel that we get these days has alcohol blended into it, and that fuel seems to have wrecked the fuel rails. I think that the water that is in the alcohol causes the oxidation of the aluminum. The older the fuel gets, the worse the fuel becomes.

Has anyone else had this issue?
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