no fuel pressure
05-18-2013, 06:14 PM
#1
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no fuel pressure A little background first... Back in fall of last year I was on my way home from work, stopped and filled the gas tank with 93 and was about to get on the high way when it started sputtering and then died. Pulled over and was unable to restart the car. After getting the car home and off the trailer, I let it sit for a bit, then went to start it for kicks and it did. I moved it around and then shut it off. The following day I started it and let it until, until it got warm and then began sputtering and died again, wouldn't restart. So I foolishly threw a new opti on it without doing much actual troubleshooting, that didn't make a difference. So I just put it away for the winter until today when I brought it back home.
I double checked all connections today before testing for fuel pressure, of which I'm getting 0 at the schrader valve. Check the pressure gauge on another vehicle just to be sure and it is working. I'm pretty sure the fuel pump is priming when the key is turned on. I've done some searching but not really coming up with much, any input would be helpful.
Vehicle is listed in my sig, has 97k miles on it. Only mods are a Granatelli maf and different throttle body.
I double checked all connections today before testing for fuel pressure, of which I'm getting 0 at the schrader valve. Check the pressure gauge on another vehicle just to be sure and it is working. I'm pretty sure the fuel pump is priming when the key is turned on. I've done some searching but not really coming up with much, any input would be helpful.
Vehicle is listed in my sig, has 97k miles on it. Only mods are a Granatelli maf and different throttle body.
05-19-2013, 04:36 PM
#2
A little background first... Back in fall of last year I was on my way home from work, stopped and filled the gas tank with 93 and was about to get on the high way when it started sputtering and then died. Pulled over and was unable to restart the car. After getting the car home and off the trailer, I let it sit for a bit, then went to start it for kicks and it did. I moved it around and then shut it off. The following day I started it and let it until, until it got warm and then began sputtering and died again, wouldn't restart. So I foolishly threw a new opti on it without doing much actual troubleshooting, that didn't make a difference. So I just put it away for the winter until today when I brought it back home.
I double checked all connections today before testing for fuel pressure, of which I'm getting 0 at the schrader valve. Check the pressure gauge on another vehicle just to be sure and it is working. I'm pretty sure the fuel pump is priming when the key is turned on. I've done some searching but not really coming up with much, any input would be helpful.
Vehicle is listed in my sig, has 97k miles on it. Only mods are a Granatelli maf and different throttle body.
I double checked all connections today before testing for fuel pressure, of which I'm getting 0 at the schrader valve. Check the pressure gauge on another vehicle just to be sure and it is working. I'm pretty sure the fuel pump is priming when the key is turned on. I've done some searching but not really coming up with much, any input would be helpful.
Vehicle is listed in my sig, has 97k miles on it. Only mods are a Granatelli maf and different throttle body.
05-20-2013, 09:51 AM
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With that many miles, wouldn't surprise me if the pump was bad. I had 2 go out on me in my LT1 car, each time I would get pressure when the line was primed with the key on, but would quickly bleed off. Sounds like once your pump gets warmed up it dies. Fuel pumps on these cars are fairly cheap, with that much mileage its a good idea to upgrade to a 255lph anyway.
That fuel pressure gauge and shrader valve is your friend, start it up an watch the pressure until it dies.
That fuel pressure gauge and shrader valve is your friend, start it up an watch the pressure until it dies.
05-20-2013, 11:43 AM
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With that many miles, wouldn't surprise me if the pump was bad. I had 2 go out on me in my LT1 car, each time I would get pressure when the line was primed with the key on, but would quickly bleed off. Sounds like once your pump gets warmed up it dies. Fuel pumps on these cars are fairly cheap, with that much mileage its a good idea to upgrade to a 255lph anyway.
That fuel pressure gauge and shrader valve is your friend, start it up an watch the pressure until it dies.
That fuel pressure gauge and shrader valve is your friend, start it up an watch the pressure until it dies.
05-20-2013, 11:53 AM
#5
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I can almost guarantee the fuel pump is bad. if you dont hear it run when you hit the key, it's bad.
There's a check wire right next to the PCM on the passenger side of the car that if you jump a wire from the positive side of the battery to that wire, it will run the fuel pump.
There's a check wire right next to the PCM on the passenger side of the car that if you jump a wire from the positive side of the battery to that wire, it will run the fuel pump.
06-07-2013, 04:23 PM
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New walbro 255 and still not getting fuel pressure. Definitely hear the pump run when the key is turned on. I tried priming the pump a half dozen times (cycling the key on and off) but no luck. I did pull the intake tube off and squirt some starting fluid into the tb and it tried to start so that made me feel a bit better. Could a fuel filter be so clogged as to not let any fuel pass through? I guess that'll be my next step, I'm sure it could use it anyway.
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06-07-2013, 09:46 PM
#8
Its got to be one of three things;
1) The fuel pump is not producing fuel pressure
2) There is something obstructing the fuel to reaching the motor
3) It is leaking the fuel somewhere
Walbro fuel pumps have been known to be Chinese knock offs. It doesn't matter if you get them from a reputable shop or not, they are everywhere and have been known to fail out of the box, or just months after being new. To my knowledge Racetronix are one of the only brands of 255lph fuel pump that have not been known to be in this vast group of Chinese knockoffs.
That being said, if you hear the fuel pump priming as you turn the key, it most likely is working at least partially. Sounds like you are on the right track checking the fuel filter. If age is a factor on items (and it sounds like it is), I would suggest replacing the fuel filter as a precaution to itself and other things. Once that has been cleared trace the entire fuel line from pump to Schrader valve. Be sure there are no kinks bends (besides the ones from the factory) or leaks. Its also possible the fuel line has popped off the fuel pump in the tank (that's happened to me before).
There's really nothing else it could be past this (at least for fuel pressure, starting may be another bag of worms), so this should eliminate your fuel pressure problems.
1) The fuel pump is not producing fuel pressure
2) There is something obstructing the fuel to reaching the motor
3) It is leaking the fuel somewhere
Walbro fuel pumps have been known to be Chinese knock offs. It doesn't matter if you get them from a reputable shop or not, they are everywhere and have been known to fail out of the box, or just months after being new. To my knowledge Racetronix are one of the only brands of 255lph fuel pump that have not been known to be in this vast group of Chinese knockoffs.
That being said, if you hear the fuel pump priming as you turn the key, it most likely is working at least partially. Sounds like you are on the right track checking the fuel filter. If age is a factor on items (and it sounds like it is), I would suggest replacing the fuel filter as a precaution to itself and other things. Once that has been cleared trace the entire fuel line from pump to Schrader valve. Be sure there are no kinks bends (besides the ones from the factory) or leaks. Its also possible the fuel line has popped off the fuel pump in the tank (that's happened to me before).
There's really nothing else it could be past this (at least for fuel pressure, starting may be another bag of worms), so this should eliminate your fuel pressure problems.
06-08-2013, 08:37 AM
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New walbro 255 and still not getting fuel pressure. Definitely hear the pump run when the key is turned on. I tried priming the pump a half dozen times (cycling the key on and off) but no luck. I did pull the intake tube off and squirt some starting fluid into the tb and it tried to start so that made me feel a bit better. Could a fuel filter be so clogged as to not let any fuel pass through? I guess that'll be my next step, I'm sure it could use it anyway.
You don't have to "cycle the key", as stated earlier in this thread there is a wire hanging out next to the PCM that will power the fuel pump. I know you have a a fuel pressure gauge, but I would suggest bumping the key for one sec. when you take the fuel filter off (with a hose going to something catching the fuel hopefully coming out of course) to see if you're getting fuel to that point.
06-16-2013, 10:18 PM
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Back from vacation and got some time to get the new fuel filter in today, pump is pushing fuel to the filter. I tried hooking up the fuel pressure gauge to the schrader valve and got nothing again. However, when I just pushed the center pin it squirted fuel out so I'm gonna borrow a pressure gauge from a friend to see if for some reason mine isn't properly opening the valve causing it to read 0 pressure.
I really appreciate all the help thus far, I haven't gotten a lot of time lately to work on the car but I can't wait for it to be back on the road.
I really appreciate all the help thus far, I haven't gotten a lot of time lately to work on the car but I can't wait for it to be back on the road.
Wrong section dude! 
. 