cwuwildcat
NAXJA Forum User
- Location
- Ellensburg, WA
what are the signs that show you your fuel pump is going out? or will it just die and your stranded?
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bad fuel pump?
- Thread starter cwuwildcat
- Start date
langer1
NAXJA Forum User
- Location
- Mineral City,Ohio
Low pressure on the fuel rail.
I too am wrestling with a fuel pump, albeit the one on my old f150. Im not really familier with the jeep system. But on my old ford, the pump comes on, when you turn the key to build pressure, but it stays on and the truck wont start. However, the pump shows 50lbs at the fuel rail.
I know this is a XJ forum, but I thought somebody might have some generaic suggestions, on things I havent looked at. Things I have checked: All relays(ECM, Fuel Pump) Engine coolant sensor, Air Temp sensor, MAP sensor, spark at spark plug, also checked the grounds to the computer(Theres three of them, 2 of them showed >5ohms and the one going to the fuel pump/rear lighting showed 11ohms). Everything I read says that ford ECM's never die, but seems to me like it is the culprit. Anyway, thank you in advance!
I know this is a XJ forum, but I thought somebody might have some generaic suggestions, on things I havent looked at. Things I have checked: All relays(ECM, Fuel Pump) Engine coolant sensor, Air Temp sensor, MAP sensor, spark at spark plug, also checked the grounds to the computer(Theres three of them, 2 of them showed >5ohms and the one going to the fuel pump/rear lighting showed 11ohms). Everything I read says that ford ECM's never die, but seems to me like it is the culprit. Anyway, thank you in advance!
xjbubba
NAXJA Member # 1524
- Location
- santa barbara, ca
A noisy pump is an indicator; hard start or loss of high-speed power are others. Check for proper fuel pressure, and do a leak-down test, especially if your experiencing longer than normal crank time at start up.
- Location
- REDLANDS, CA. (SoCal)
There is a 3" length of rubber fuel line than is between the pump and the pick up tube that runs to the bottom of the tank. The tube, which is also inside the tank can/does rot. This can either allow the pump to pull air with the fuel or disconnecting completely, pull only air. You can hear the pump run but not get pressure/enough pressure at the fuel rail.cwuwildcat said:
langer1
NAXJA Forum User
- Location
- Mineral City,Ohio
Do you have spark? Will it start with starting fluid?91xjtim said:
langer1
NAXJA Forum User
- Location
- Mineral City,Ohio
Well the lets guess do you have TBI or MPFI? 50# of pressure sounds way high.91xjtim said:
langer1
NAXJA Forum User
- Location
- Mineral City,Ohio
I understand then you need to check your IAC or your MAS91xjtim said:
xjbubba
NAXJA Member # 1524
- Location
- santa barbara, ca
Not sure about the Ford system, but I think most MPFI systems are similar. On the older GM systems (pre OBD ll), the pump comes on for ~2 secs, then turns off if the ECM doesn't sense ignition pulses. The 2secs is a set ECM parameter. Have you checked for spark? Just because the fuel pump is always running doesn't mean the engine won't run, but does indicate a problem with the ECM, fuel pump relay, or associated circuitry.
