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All symptoms point to a failure of the pre-pump or lift pump in the gas tank. Had trouble running yesterday, during the 1.5 seconds that the main pump runs prior to start it was occasionally noisy, the car stalled during a sharp turn once, etc.
However, I am a bit confused by the info on diagonsing the pre-pump in the FAQ. There are some entries that say if the pre-pump fails, then the main pump will run for more than 1.5 seconds when turning the key to KPII. Mine does not. It always shuts off after 1.5 seconds. Further, I thought the length of time the main pump runs prior to engine start was controlled by a circuit in the EGI computer that only energized it to build pressure for start-up, not by the actual fuel pressure itself. The pressure is controlled by the FPR on the fuel rail bypassing excess pressure/fuel back to the tank.
Anyway, if I put the key to KPII, the main pump runs for about 1.5 seconds, but even with the fuel cap off, and an automotive stethescope inserted 18" down the filler pipe, I hear absolutely nothing going on in the tank. No buzz, no hum, nada, zilch, nyet, etc. Kind of points to pre-pump failure, don't you think?
Am in the process of pulling out the pre-pump now, but look forward to your comments and ideas. Like how to bench test the pre-pump. One FAQ article says don't, another says you can energize the assembly to test the fuel level sensor. Which is it? Can I power up the in-tank pump for a second on the bench to see if it works?
Thanks guys.
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Scott Cook - 1991 745T, 1985 RX-7 GSL-SE, 1986 Toyota Tercel (Don't laugh, it is reliable, faithful AND gets 41 mpg!)
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