I have replaced the pump 2 times the week and it bad again could it be a bad regulator it 1991 with a 3F-E
No fuel pressure 1991 with 3F-E (1 Viewer)
- Thread starter JACOB 1991
- Start date
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Please put together a coherent statement and include what symptoms you are experiencing as well as a detailed list of what you have done so we have even a remote chance of helping you diagnose your issue.
If you've replaced it twice and it still didn't fix it, then that's not the problem.
- Thread starter
- #3
It ran alright for a day after i replaced the 1st one but it did smoke a little and had a
hesitation at idle . It did have trouble starting when it was warm 1 time early today then the next time i turned it off and started again it sputtered one time and would notfire it had good spark but no fuel pressure
Why did you replace it the first time?
The fuel pump on these does NOT run until the engine is actually cranking. You can do a bypass test, but you kinda need to know what you're doing.
Go here to start with your diagnostics. Upper left radio button. (3F-E EFI Diagnostics)
- Thread starter
- #5
It was the first thing that came to mind when it had no fuel pressure the first time
How and where are you measuring fuel pressure?
Do you have the FSM for the truck?
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- #7
There was no fuel at the fuel rail but it only when the engine is hot has to run for a 1/2 hour then you turn it off and it will not start but if you let it sit for 4 to 5 hour starts right up
Do you have a FSM?? factory service manual
Have you tried bypassing the fuel pump logic?
Have you taken any voltage readings at the pump?
- Thread starter
- #9
I have the fsm and the pump has voltage but it aso cool and how do you bypass the fuel pump logic
Is the CEL illuminated with the key in the ON/RUN position before you crank the starter when you have a "no start" condition?
No CEL=no start. That should be the very first thing to check.
To bypass FP logic, connect pins 8 (FP) to 1 (B+) in the check connector mounted on the right side of the firewall, below the wiper motor. Assuming the CEL is illuminated with the key in the ON/RUN position as mentioned above, that will cause the fuel pump to run with the key ON. Use this for diagnostic purposes only.
No CEL=no start. That should be the very first thing to check.
To bypass FP logic, connect pins 8 (FP) to 1 (B+) in the check connector mounted on the right side of the firewall, below the wiper motor. Assuming the CEL is illuminated with the key in the ON/RUN position as mentioned above, that will cause the fuel pump to run with the key ON. Use this for diagnostic purposes only.
- Thread starter
- #11
I will try that and get back with you
Hi, Sounds like Efi fuse. It gets hot and then needs time to cool down to start. Mike
