1992 460 Fuel Problem
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1992 460 Fuel Problem
My 1992 460 F250 does not start! I have found that it is not getting enough fuelpressure to the rail. It starts with starter fluid sprayed into the intake then runs rough and dies. The truck has dual tanks with a pump in eachtank. The pumps sound fine when each tank is selected and the key is turned.
I have already replaced the filter, fuel pressure regulator, andfuel pump relay with no success. I don’t think both pumps can failat the same time. Can they? I have read up on the issue and don't know what to do next. This is my daily driver! Can anybody provide any guidance?
I have already replaced the filter, fuel pressure regulator, andfuel pump relay with no success. I don’t think both pumps can failat the same time. Can they? I have read up on the issue and don't know what to do next. This is my daily driver! Can anybody provide any guidance?
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Is it possible for both pumps to fail at the same or almost the same time? Absolutely. Is it likely? Probably not -- but "probably not" is not the same as "absolutely not"!
When you turn the key on and the pumps run, do they run for just a couple of seconds or do they keep running until you turn the key off?
What pressure did you read on the rail? Did you get that pressure by cycling the ignition key until the pressure stopped increasing, or did you jumper the fuel pump and signal return pins in the underhood DT connector?
Once you get pressure and turn the key off, how long does it take to lose the first 5 PSI? (Specifications say one minute or less.)
When you turn the key on and the pumps run, do they run for just a couple of seconds or do they keep running until you turn the key off?
What pressure did you read on the rail? Did you get that pressure by cycling the ignition key until the pressure stopped increasing, or did you jumper the fuel pump and signal return pins in the underhood DT connector?
Once you get pressure and turn the key off, how long does it take to lose the first 5 PSI? (Specifications say one minute or less.)
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When the key is turned the selected pump only runs for a few seconds then turns off. Is this not normal?
My pressure is only 8 PSI. I got it by cycling the key then lost pressure right away!
Once it starts with starter fluid it only runs with High RPM. Both pumps seemed to be working fine a week ago. I normally only use the front tank and felt a few abnormal hesitations before it died and wouldn’t start.
The pumps are old but I don’t think they are the problem because at least one should work. Could I not be getting enough electricity to the pumps? Is there anything else I can check or replace before I drop both tanks?
My pressure is only 8 PSI. I got it by cycling the key then lost pressure right away!
Once it starts with starter fluid it only runs with High RPM. Both pumps seemed to be working fine a week ago. I normally only use the front tank and felt a few abnormal hesitations before it died and wouldn’t start.
The pumps are old but I don’t think they are the problem because at least one should work. Could I not be getting enough electricity to the pumps? Is there anything else I can check or replace before I drop both tanks?
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From: Easton,Ks
But you need to ground pin #6 of the self-test plug and turn on the key and see what fuel pump pressure you have then. Try this with each tank.
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I grounded pin #6. The pressure remained at 8 PSI. The selected pump ran continuously until the key was turned off. When I switched it to the rear tank it sounded different then the front!
The rear pump has a different hum to it and does not sound as good as the front pump. When I was next to the rear tank as it was running it also sounded like there was gas moving around in the tank.
By doing this test did I rule out an electrical problem and find that it’s a pump issue? Should I replace the rear pump? Why doesn’t aleast one pump give enough pressure?
I appreciate the help!
The rear pump has a different hum to it and does not sound as good as the front pump. When I was next to the rear tank as it was running it also sounded like there was gas moving around in the tank.
By doing this test did I rule out an electrical problem and find that it’s a pump issue? Should I replace the rear pump? Why doesn’t aleast one pump give enough pressure?
I appreciate the help!
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From: Easton,Ks
The only thing I can think of that will effect both tanks in that manner is the Fuel pressure regulator valve being held off its seat.
OR
Both high pressure check valves in both FDM wide open when their related pump is not running.
The can happen as it did with the 1993 F-series truck that came out with bad FPR's that let the fuel pressure go too high and blow out the valves.
Does the tank that pump is not running in get filled from the running tank pump?
OR
Both high pressure check valves in both FDM wide open when their related pump is not running.
The can happen as it did with the 1993 F-series truck that came out with bad FPR's that let the fuel pressure go too high and blow out the valves.
Does the tank that pump is not running in get filled from the running tank pump?
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