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Fuel delivery issue electrical
Posted 28 August 2012 - 11:28 PM
note: NOT a clog in the fuel lines or filters already ruled that out.
Pulled the pump out and bench tested it: okay it works.
Replaced the fuel pump relay: IT WORKED (engine ran) FOR 5 MINUTES, then stopped.
Replaced pump relay a second time: nothing.
Jumped pin 2-4 at the relay socket (to bypass the relay): no change.
Measured 12 volts at the connector to fuel pump (at fuel pump end, in bypass mode)
I'm thinking it may be:
A bad ground somewhere in the circuit?
A short in the wire between the connector and the pump itself?
(but why did it work when I replaced the relay the first time?)
Here is a clue, when I replaced the pump replay the first time, then it stopped, I felt the relay itself and it felt really warm. Maybe that's normal...
Okay, what am I missing or overlooked here?
Posted 28 August 2012 - 11:42 PM
Not uncommon for a pump to be intermittent when it fails.
2 larger (somewhat) wires at the pump. One is 12V (possibly Brown, possibly Black/Red). The other should be Black, is chassis ground. Could just be a loose connection. The fuel pump wires come into the car somewhere under the back seat IIRC, and there is/might be a connector there.
Posted 29 August 2012 - 12:13 PM
Then you have access to the two wire voltage connector to the pump.
If you connect 12v to the pump side, with a hose pulled off the fuel filter you can check pump for performance, installed in the tank.
Learned all this last week on my fuel filler pipe project. My pump was drawing 4 amps as it was pumping fuel.
Posted 30 August 2012 - 01:53 PM
The fuel pump most likely uses a controlled return to ground that may go through the ECU. If the ignition system isn't working the ECU will shut down the pump by opening the pump circuit ground connection. Have you checked for spark to the plugs. Check all the fuses also and make sure they are ok.
Posted 15 September 2012 - 12:38 PM
Please any experts here want to give an opinion or bust some myths here?
Posted 15 September 2012 - 03:57 PM
OK a solution Agree with ? bout it prolly be the pump.(relay failure rare.)Wise to keep the tank above a third, keeps pump cooler, reduces pumping effort etc Were me, since subie F pumps are so easy to swap, I would a used one, just me. Maybe a pay to pull yard
Edited by propane, 16 September 2012 - 01:02 AM.
Posted 15 September 2012 - 09:02 PM
Posted 16 September 2012 - 11:20 AM
A bad pump can sometimes be "fixed" by running a new circuit directly from the battery because of the stronger, direct power.
I suggest getting a cheap pump on Ebay, just the pump, not the assembly. If anything, just to use to test the circuit. If it all works out, then save up or shop around for the pump that you want.
I've used those before with great success. In a Lumina I had, ans S10 that I had, and in my dads Ranger. They are all still working. The lumina was 3 years ago, the S10 2, the Ranger 1.
This is one from the same seller that I bought mine,
Posted 20 September 2012 - 10:28 PM
Posted 21 September 2012 - 02:50 AM
Posted 21 September 2012 - 09:52 AM
Posted 21 September 2012 - 09:58 AM
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