I have a 92 f150 been at it for days and still wont start. I have spark and fuel pressure Two things I cant figure out is my fuel pump runs all the time, when I turn on the ignition it wont prime and stop it keeps running and my fuel pressure stays the same, in spec's. I alsotried to do the self diag test, using a jumper wire on theDLCwith the check engine light wont work, so I barrowed a snapon diag tester and cant get it to power up on the truck. I verified the tester is working on my car but nothing on my truck. can anyone please help. Thanks

 

Have someone check your computer, I had an 93 and did very similar, would start but idol fine the when in gear run like crap and then finially not start, I carried it to a shop and they said it was the fuel pump, I replaced to no avail, then i check the voltage at the fuel pump and was only getting 3volts instead of 9 or 12 what ever the battery was. I had some moble mechanic come by and check it out and in 3min. said the computer was bad, charged me 75$ for the time, I went to advance auto and got a new one for 100$ pluged it in and good as new. The computer is under the break master behind the drivers front wheel. real easy to change out took about 15min. You need the numbers off the cover to order and the new one didn't have the numbers on it so write them down and save for the future. Good luck.

 

Well, the pump running all the time is a good indication that the pcm is not turning it off. And no self test, tells you the pcm is not powering up. Check the pcm relay in the left front fender area. Should be two relays there, one for the fuel pump and one for the pcm. [sm=mail.gif]