Still starts, but dies quickly after fuel pump install!
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Joined: Jun 2000
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From: Bethlehem, Ga
Car: '88 Trans Am GTA
Engine: 5.7L L98
Transmission: 700r4
Axle/Gears: 3.27 Aussie 9 Bolt
Still starts, but dies quickly after fuel pump install!
Well, I just got through installing a brand new Holley 255 pump. It was the only thing on the fuel system that hasn't ever been replaced.
I'm still getting a "start, run a few seconds, then die" situation. I thought maybe the fuel pressure was off, so I adjusted it and discovered it was still doing strange things. After playing with it a few minutes, I got the bright idea to swap out the Accel gauge and replace it with another gauge on a hose so I could watch it from the cockpit.
Here's what's happening...
When I turn the key, the pressure reads 80psi until the pump finishes priming, then drops to 25psi. At that setting, it will run at 50psi for a few seconds, then die.
I backed the screw off half a turn, then it would read 70psi until the pump finished priming, then drop to 25psi. It wouldn't start at all, but the gauge was reading around 35psi.
On this last round, I advanced the screw a quarter turn, halfway between the previous two points and it read 60psi until the pump finished priming. It still drops down to 25psi afterwards. It will run, but only for a few seconds, at 38psi then die.
All of this was with the vacuum gauge off the regulator. No matter how I turn the screw, I can't get either gauge to read anything other than 25psi with the key on, engine off.
The pressure regulator is new. The diaphragm in it is new. The only thing I can figure is there isn't a spacer inside between the spring and the screw so the screw goes down into the dimple on the spring cap. I don't see how that would cause any problems though. The regulator itself didn't come with one.
I also replaced the pulsator with a new one.
The filter is new.
Lines aren't crossed.
Luckily though, the pump swap wasn't for nothing. I did find that the old pump rattles when you shake it. That doesn't sound too good.
Can anyone give me any ideas?
I'm still getting a "start, run a few seconds, then die" situation. I thought maybe the fuel pressure was off, so I adjusted it and discovered it was still doing strange things. After playing with it a few minutes, I got the bright idea to swap out the Accel gauge and replace it with another gauge on a hose so I could watch it from the cockpit.
Here's what's happening...
When I turn the key, the pressure reads 80psi until the pump finishes priming, then drops to 25psi. At that setting, it will run at 50psi for a few seconds, then die.
I backed the screw off half a turn, then it would read 70psi until the pump finished priming, then drop to 25psi. It wouldn't start at all, but the gauge was reading around 35psi.
On this last round, I advanced the screw a quarter turn, halfway between the previous two points and it read 60psi until the pump finished priming. It still drops down to 25psi afterwards. It will run, but only for a few seconds, at 38psi then die.
All of this was with the vacuum gauge off the regulator. No matter how I turn the screw, I can't get either gauge to read anything other than 25psi with the key on, engine off.
The pressure regulator is new. The diaphragm in it is new. The only thing I can figure is there isn't a spacer inside between the spring and the screw so the screw goes down into the dimple on the spring cap. I don't see how that would cause any problems though. The regulator itself didn't come with one.
I also replaced the pulsator with a new one.
The filter is new.
Lines aren't crossed.
Luckily though, the pump swap wasn't for nothing. I did find that the old pump rattles when you shake it. That doesn't sound too good.
Can anyone give me any ideas?
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