1994 4.9L engine will not start, what can it be?

We checked the compression and it seems pretty good. The EEC test engine on, not running gives me an air circuit error (I don't think that really has much to do when not running) No other relevant codes. The grounding issue has been suggested, and I ran some continuity checks and everything related to the EEC seems good. I used one of those injector node kits (the blinking light testers) and we even took the injector rail out and I held it while my partner cranked the engine and we have injectors firing. My suggestion was to pull the timing cover off and look at the cam gear, but my partner said he had it running with starting spray, but I've never heard it run with or with out spray....so I can't confirm.

If you are referring to the large air flow control near the air filter on the fender, then, no this one doesn't have one....My 1994 5.oL has one but the 4.9L does not....There is the idle air valve on the throttle body, but not the air intake before that.

I know where the HO2, and the ECT sensors are located, but not sure where the ACT is. Is that near the front of the engine before #1 injector on the intake??

I found the ACT sensor...I'm going to go give it a try in a little bit, and will let you know how it went. Thanks.

I tried doing what you suggested and still nothing. I'm still leaning towards the cam gear lost a tooth..... The owner said it began running bad and steadily got worse until it just quit one day. He took it in and who ever that was said his timing (distributor) was out of whack. They reset it and it ran again (but not real great) and then it just quit again and that was the last time it's run. I think the can gear has lost a tooth and jumping one tooth every now and then.......Now it is too far out to run....what do you think?

We already replaced the drive gear on the distributor while we had it apart changing the pick up in the distributor. The cam gear looks good also...... Do you know of an easier way to check cam to crank gears short of pulling the cover off?

The 4.9L doesn't have a chain...it's gear to gear...... Slop will not be apparent.....If anything there would be a tooth broken letting the gear jump time..... I guess we're looking at pulling the cover off then...It was suggested I go to TDC on #1 then back up crank 108 degrees and see when the intake valve begins to open.... should open right close (a few degrees off BDC) turning backwards...... Does that sound right to you? Then the next step might be to pull cover....

Sorry...that should have been 180 degrees not 108....my bad

I have done a motor swap in my 1994 4.9 and this motor will not turn over the starter is good and all the other wiring hardest the motor is a 1992 4.9 but i don`t know whats is wrong

I have a 1996 f-150 with the 4.9L and I’m having the same issue, I changed literally everything, crankshaft sensor, cap and rotor button, plugs and wires, coil pack, new distributor, I’m not getting spark, I have good power in the harness. I was wondering if you ever found out the problem