sonny32

I have been trying to figure out why my 1990 f-150 fuel injected,straight -6 won't start if I can hear the fuel pump running...If I turn the key and hear the fuel pump briefly and it cuts off,, then the truck starts right up..... If i turn the key and the fuel pump continues to run the engine gets no gas and will not start (unless I use starting fluid,and then I have to keep the rpm's up or it will cut out,, but in a minute or 2 the fuel pump noise quites and it runs properly) Thanks for any and all ideas
sonny32

Steve83

I've seen that symptom described a few times, and in all cases, the final diagnosis was a bad EEC. Now, I don't recommend that you jump to that conclusion without thorough diagnosis, but don't be surprised if that's what you find.

My first recommendation is to cut off the EEC PWR & FP relays, and install Bosch/ISO-style relays, as shown in this & the NEXT few pics:



It probably won't fix your symptom, but it needs to be done.

For actual diagnosis, run a 12V test light from a 12V source to the FP relay trigger (ground) wire in the DLC under the L hood hinge near those relays. When the pump stays on (engine NOT turning), observe the light. If it stays on, then the EEC is incorrectly holding the relay on.

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sonny32

thanks Steve,,, It was the EEC,,and I changed everything to Bosch as you said,,,it runs like new,,
Thanks again
Sonny 32