My fuel pump will prime when I turn the key to the "On" position, but after the initial prime it will not come on with the engine running. Fuel pressure starts at 40 psi, but bleeds off and the engine eventually stalls. I've tested it by running direct power to the pump, and in that situation the fuel pressure doesn't bleed off and the engine continues to run (but not well).
In addition to testing fuel pressure, I just swapped with a known good ECU, so that's not the problem. Is there a difference in how the fuel pump gets power during the prime cycle versus the normal engine running condition? I've looked at the wiring schematic (EF&EC-9 in my copy of the FSM) but I cannot figure that out. I've looked at this thread which covers re-wiring the pump to bypass voltage control from the ECU... but I don't understand all of it.
There is a timer that must reset before the pump will prime again. I hear the relay click in the engine bay about 5 seconds after I turn the key off. Is that timer/relay circuit keeping the pump from running? Comments in other threads about the fuel pump mention the need to ensure all ground connections are secure and well-bonded, but this seems like something else (since the pump runs in one mode but not the other). I'm still going to check them, but thought I'd see if there are any other things I should check as well.
Suggestions and opinions welcome...
In addition to testing fuel pressure, I just swapped with a known good ECU, so that's not the problem. Is there a difference in how the fuel pump gets power during the prime cycle versus the normal engine running condition? I've looked at the wiring schematic (EF&EC-9 in my copy of the FSM) but I cannot figure that out. I've looked at this thread which covers re-wiring the pump to bypass voltage control from the ECU... but I don't understand all of it.
There is a timer that must reset before the pump will prime again. I hear the relay click in the engine bay about 5 seconds after I turn the key off. Is that timer/relay circuit keeping the pump from running? Comments in other threads about the fuel pump mention the need to ensure all ground connections are secure and well-bonded, but this seems like something else (since the pump runs in one mode but not the other). I'm still going to check them, but thought I'd see if there are any other things I should check as well.
Suggestions and opinions welcome...
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