I have a crank no start. I had spark but no fuel pressure. Only 3.6 volts at the pump. Checked relay and it worked fine but was only sending 6.3 volts to the puny. Checked voltage from the pcm and only had 6 volts. Took out the computer and replaced the capacitors but still only got 6 volts. Checked voltage going into the computer and had 12.6 volts so the problem seems to be something with the computer. Does anyone know of anything else in the computer Thant I should be checking? I had 1993 5.0 fox body
-
Hello there guest and Welcome to Fox Body Mustangs forum, This forum is intended to be used by enthusiasts of the Fox body Ford Mustangs (1979-1993)!
To gain full access you must Register. Registration is free and it takes only a few moments to complete.
Already a member? Login here then!
Computer voltage
- Thread starter Dem Boyz
- Start date
broncojunkie
Well-Known Member
Have you checked grounds? I would check all of them. I believe there is a ground wire right there at the ecm. Also check the ground strap going from the engine to the chassis. Iirc, the negative battery cable goes to the engine block. With factory motor mounts, the test of the chassis has to ground through that ground strap. On my pace car, I run solid motor mounts. No engine-to-body ground strap needed.
A quick test would be to take a pair of jumper cables and ground from the engine to the body (clean metal, of course) and then check voltage again.
A quick test would be to take a pair of jumper cables and ground from the engine to the body (clean metal, of course) and then check voltage again.
Thanks for the suggestions, I’ll check
Redtwilight
Shinigami
There is also a ground for the computer on the fender apron right at the upper corner of the battery near the starter solenoid. Check to make sure the connections are good there as well as the small wire going from the same spot back to the negative terminal of the battery.