I have a 1993 E-350. My van suddenly died and it seemed the fuel pump was bad as when striking the side of the fuel tank it suddenly came to life, I replaced the fuel pump and 2 days later it died in the same way. Then it would work, but if you shut it off it wouldn't restart as the pump wouldn't work. I hooked up to an OBDII and got code for Fuel Pump Secondary Low Voltage?? Any Help???
Check the fuel pressure regulator on the fuel rail pull the vac-*** hose off some times they get a hole in
the diaphragm and when this happens they will load the intake up with gas and after you get it started
you have to keep giving it more gas to keep running and eventually this can fill the crankcase to the point of wydalock most ford dealers and other mechanics miss this till it is to late
very easy to check just pull hose off and start or try to start watch for fuel to come out of the regulator
good luck tlw
1994 econoline fuel system electrical
Vehicle Application
Escort/Tracer, Crown Victoria/Grand Marquis, Thunderbird/Cougar, Town Car, 5.0L Mustang, Aerostar, Ranger, Explorer, E-Series and Bronco.
Fuel Pump Circuit Operation
When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM).
When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.
After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."
System Diagnosis
Note: Grounding the FP lead at the DLC will allow the pump to run continuously with the ignition switch on.
You need to find out where the open circuit is. Likely at the connector to the fuel pump unless there is also a jumper harness with another connector. Check for a pin push out.
Also, the fuel pump id designed to run all the time the engine is running. There is a fuel pressure regulator on the engine fuel rail that maintains @ 40 psi and returns excess fuel back to the tank through a return line. So, flooding out should not be being caused by the fuel pump.
Connect a fuel pressure gauge to the schrader valve on the fuel rail to monitor pressure. Loks like a tire valve stem.
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You need to check the wiring connections and the ground to the fuel pump (the culprit in most cases is the ground circuit but you could have a deteriorated plug some where in the wiring to the front of the vehicle)
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I was told there was a power reducer in the line between the relay and the pump that would be considered the low voltage secondary to the fuel pump, but I have no idea what or where this would be. I also found on an F-150 page there was a ceramic voltage reducer mounted on frame near radiator that could cause such an issue. I can not check the voltage to the pump without removing the tank. I know that the relay is working as I purchased a new one and also did the swap of the relays and always get a clicking of the relay when the key is turned on. It now doesn't power up at all. I even used the OBDII and ran the fuel pump test and got nothing.
I moved the wiring harness on top of the tank and suddenly the pump is working, It started and ran fine for about 3 minutes and then it loaded up and flooded itself out.. Now what?? I let it sit about five minutes and restarted it and got the same result. If I reved it it ran but seemed to be flooding it out still. Any ideas here??
I got it running, I simply put a hot wire from the fuse box directly to the hot wire on the fuel pump. I still get the code for fuel pump secondary PCM to ground but it runs and runs good at that.
check for 12 volts at the fuel pump.
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