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So I have a 1992 f150 5.0 and I’m having an issue with both fuel pumps not working. I can get the rear pump to work if I ground pin 6 on the test connector. I was told that I have a grounding issue and that the problem was with the ground coming off the battery. I checked that and that ground is good so I don’t know where else to look. Also when I ground pin 6 to activate the pump, the fuel pressure on the fuel rail goes to about 40 and then slowly bleeds off. Any ideas where to go next?
So if you dont ground pin #6, and you just turn the key to the run/on position, and you dont hear your pump run for a second or two, it usually means bad ECM/PCM, and removing it and opening it up would be next move... if your relay, and inertia safety switch are good, prolly are, because grounding it turns them on.
Ok I’ll pull the ecm and see what it looks like. Question, if I pinch off both the supply and return line with the fuel pressure built up and it still drops quickly then it’s the injectors leaking right?
Thank you sir! So as far as the no fuel pumps working issue goes, I pulled the ecm and found that it had often water in it at some point and burned up a portion of it. I’ve got a new ecm coming so we’ll see what happens
Well no, it did not run. I’m not sure when the last time it ran was. Even though I could get the fuel pump to run by grounding pin 6, it still wouldn’t fire. I just assumed it was a distributor problem because the previous owner said it may be but the new ecm may fix that as well. Thank you for that link, that is very helpful!
