It was running and just stopped one day, I have replaced the fuel pump, fuel pressure regulator and I still have no fuel pressure! I am suspecting it could a bad injector, but if 1 was bad, i would think I would get more than 2-5psi, it was doing this before I replaced the pump & regulator. I have a Hotwire kit, checked relay & fuses and all are good, have power. Could it be a bad injector or what else? Could it be a bad ignition module or? just starting to think it may not be a bad injector? When powered on the fuel pressure gauge may jump 2-5psi and drop immediately and it did this with both the old & new fuel pump & regulator. Just looking for some help/direction of where I should trobleshoot next.
No Fuel Pressure!
- Thread starter twstdv6
- Start date
John Larkin
Sublime Master of Turbology
- Joined
- May 25, 2001
Fuel pressure is resistance in the line caused by the fuel pressure regulator restricting the fuel flowing to the return line. Take the schraeder valve out of the end of the test port on the fuel rail and clamp a long clear line over the end. With the key one, apply 12v to the white wire with the black connector behind the alternator. That will make the fuel pump run continuously. See if fuel flows out the hose with really good pressure (into a can of course).
Tested fuel pump relay and it has power & clicks on when key is turned on & clicks off when key is turned off, also took fuel pump relay & Computer (ECM) from my 87 GN as a tester and same results. Tested Fuel rail port with wire behind the alternator, it's not shooting out, but it flows good a freely. I will check fuel filter and remove the throttle body and use a inspection camera to look at the 42lb blue top injectors, to check for a bad or leaky one, before I go back into the tank to check the line and so forth. I can hear the fuel pump turn on and run for a few seconds, pressure is only 2-5 psi at rail and has new fuel pressure gauge. I got it to start, but only ran for a few seconds and cut off, because of no pressure i'm sure, but why don't I have any pressure is the question...Haha haha, it's funny, but not funny...I need to figure this out!
Last edited:
- Joined
- May 28, 2001
In tank hose leak....
1 inj stuck open will cause a psi drop, but will also fill the cyl w/ fuel. Try to crank it, and you may find the piston in the oil pan.
If you think it's an inj, run a couple prime cycles, then pull the plugs.. What do you see?
1 inj stuck open will cause a psi drop, but will also fill the cyl w/ fuel. Try to crank it, and you may find the piston in the oil pan.
If you think it's an inj, run a couple prime cycles, then pull the plugs.. What do you see?
captndave737
Well-Known Member
- Joined
- Feb 14, 2006
I had a fuel pressure issue where the relays all checked out, had voltage to the connector to the fuel pump etc. All it was was a poor connection where the hot wire relay seated. I took a screwdriver and bent the female connector to make a tight connection and problem solved after a 175 mile tow.
I cant tell you how many problems I've had on this car that are traced to the connectors. After 27 years of vibration things loosen up and now the first thing I look for are bad connections and 90% + of the time it will be the problem.
I cant tell you how many problems I've had on this car that are traced to the connectors. After 27 years of vibration things loosen up and now the first thing I look for are bad connections and 90% + of the time it will be the problem.
Finally got around to dropping the tank, and as soon as I got the pump out, I seen the pulsator was barely hanging on. This is a friends car, he changed the pump, now how in the world can someone just not see the fuel 
is not going to flow. He just stuck the pulsator on their, wasn't tight at all. So I had to ask him what is this you didn't see that! And we laughed, I got the new line on and tank back in, finally got fuel pressure and started it up, it ran for few seconds and cut off! So I'm checking connections and wires, fuses all over again, then he comes and says check the computer, it came with 3 different chips and his employee had been switching them out trying to start the car . So I take a look, had a thrasher chip in it and not start, tried all three and one chip did the trick and he was up and running. Did a few adjustments under the hood and he took it out for a test drive, he just bought the car ,only had it for a few months. All this for a fuel line he didn't install, he owns a body shop, I told him to stick to that and don't touch anything. lol…
is not going to flow. He just stuck the pulsator on their, wasn't tight at all. So I had to ask him what is this you didn't see that! And we laughed, I got the new line on and tank back in, finally got fuel pressure and started it up, it ran for few seconds and cut off! So I'm checking connections and wires, fuses all over again, then he comes and says check the computer, it came with 3 different chips and his employee had been switching them out trying to start the car . So I take a look, had a thrasher chip in it and not start, tried all three and one chip did the trick and he was up and running. Did a few adjustments under the hood and he took it out for a test drive, he just bought the car ,only had it for a few months. All this for a fuel line he didn't install, he owns a body shop, I told him to stick to that and don't touch anything. lol…Similar threads
