Fuel pump works...but no pressure at fuel rail??
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Car: 1989 GTA
Engine: 350 TPI L98
Transmission: 700R4
Fuel pump works...but no pressure at fuel rail??
Hey guys. I've been messing with this for three days now and I still can't figure out why I have no pressure at the rail ( there is a gauge on it). Here is the chain of events which got me to where I am now...
First: Fuel pressure regulator died because the car sat for too long and ate the diaphrams. I replaced that with a Holley AFPR and tried to start it, but then the fuel pump wasn't turning on.
Second: Since the fuel pump wasn't turning on I checked the fuse, and it was bad so I replaced it with a new 20 amp. The fuel pump still didn't turn on.
Next I replaced the fuel pump relay, because I could not hear the old one clicking over.
I put 12 volts right to the pump and it ran fine. I then had somebody turn the key and I checked the voltage to the body connector for the fuel pump, and I only had a little over 6 volts coming out... Which two wires to I touch to get the proper reading at the body connector? I touched them in every combination and still only got 6 volts.
Why would I have lower voltage going to the fuel pump at the body connector? What else do I check now in order to get this rectified? Any help would be greatly appreciated.
First: Fuel pressure regulator died because the car sat for too long and ate the diaphrams. I replaced that with a Holley AFPR and tried to start it, but then the fuel pump wasn't turning on.
Second: Since the fuel pump wasn't turning on I checked the fuse, and it was bad so I replaced it with a new 20 amp. The fuel pump still didn't turn on.
Next I replaced the fuel pump relay, because I could not hear the old one clicking over.
I put 12 volts right to the pump and it ran fine. I then had somebody turn the key and I checked the voltage to the body connector for the fuel pump, and I only had a little over 6 volts coming out... Which two wires to I touch to get the proper reading at the body connector? I touched them in every combination and still only got 6 volts.
Why would I have lower voltage going to the fuel pump at the body connector? What else do I check now in order to get this rectified? Any help would be greatly appreciated.
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Car: 1989 GTA
Engine: 350 TPI L98
Transmission: 700R4
Ok update on the problem. I now have 12 volts to the connector, the pump works when I put 12 volts right to it. So it would have to be the connector not transferring the power. I put power to the pump for about 5 seconds and then checked pressure, and it was only 10 psi though. I'm thinking I have the AFPR adjusted way off and it isn't letting it get high enough. Which way do you turn the Holley afpr to raise pressure?
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Car: 1989 IROC-Z
Engine: 5.7L EFI LTR setup
Transmission: T-5 World Class
regulator ....lefty losssy ...righty ...tighty. Do a continuity test on all wires in the system .
I am guessing here ( someone chime in please) but I am thinking the pump on gets a certain voltage vs throttle position ????? like at idle maybe 6 volts ....wide opes 12 volts ???
Something to look into anyhow.
I am guessing here ( someone chime in please) but I am thinking the pump on gets a certain voltage vs throttle position ????? like at idle maybe 6 volts ....wide opes 12 volts ???
Something to look into anyhow.
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Car: 1989 GTA
Engine: 350 TPI L98
Transmission: 700R4
Thanks for the help. I messed with the connector and straightened out the pins, cleaned up the connectors and put dilectric grease in and now the pump turns on. Now that the pump is turning on correctly it has become glaringly obvious that my fuel pump is toast. The best way I can describe the noise it makes is a dying whale. So advance auto has a pump in stock so I'll throw that in tonight and hopefully be on the road tomorrow.
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Car: 1989 GTA
Engine: 350 TPI L98
Transmission: 700R4
Well I got rained out on the pump install seeing as my dad's corvette gets garage priority over mine. In about an hour I got the exhausts off and all of the suspension dropped so all that is left is unbolting the tank, disconnecting the lines and lowering it out. That will have to wait until another day though because I have too much going on this weekend.
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Car: 87 trans am
Engine: 305
Transmission: T5
Axle/Gears: 3.42 SLP rear
I'm having the same problem, but my pump is new. I have no pressure on my gauge, but my pump primes and I seem to have correct voltage. If the pressure regulator goes I'd have no pressure?
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Car: 91-Z28
Engine: SLOW ONE
Plug or crimp off the return line and see if you get any pressure, FPR might be sticking open.
My 91 when I bought it had sat in a barn for about 5 years, when I went to crank it the fuel pump would run but no pressure. The rubberline in the tank on the pump had busted.
My 91 when I bought it had sat in a barn for about 5 years, when I went to crank it the fuel pump would run but no pressure. The rubberline in the tank on the pump had busted.
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Car: 87 trans am
Engine: 305
Transmission: T5
Axle/Gears: 3.42 SLP rear
The fuel filter is only a few months old... I haven't tried checking in the tank as I just changed the pump, but maybe the little connector piece could be loose. Fuel flows out of the engine side of the filter, but not out of the hoses on the engine. Maybe not enough pressure to make it there? Also the voltage to the pump is around 7, but the battery is still at 12.35. I'm hoping it's just clog somewhere, but it's driving me bonkers.
edit - almost forgot. Is it normal for the oil pressure gauge to peg if I'm just switching to the ON position?
edit - almost forgot. Is it normal for the oil pressure gauge to peg if I'm just switching to the ON position?
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Car: 88 Firebird
Engine: 302 SBC
Transmission: T-5
Axle/Gears: 4.27 Dana 44
If I was to test for a plugged line, I would connect air pressure on the engine connections and blow it back to the filter. Hard to imagine a plug in the line.
If the pump blows gas out of the filter it should have no problem pushing it to the engine bay.
If the pump blows gas out of the filter it should have no problem pushing it to the engine bay.
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Car: 87 trans am
Engine: 305
Transmission: T5
Axle/Gears: 3.42 SLP rear
I blew air threw the line, but it seems ok. Pretty much the same results. Turn key, pump primes, relay clicks off. no pressure in the rail. I'll have to check the tank tommorow, I'm seeing some folks tonite.
What am I missing?
What am I missing?
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Car: 1989 GTA
Engine: 350 TPI L98
Transmission: 700R4
Well I ended up changing my fuel pump and everything works perfect now. In my case the pump still worked, but was only supplying 10psi, which is no good. I put the new pump in and instantly got 40psi at the rail with a turn of the key. So just because the pump turns on, doesn't mean it is still ok.
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