What is the issue?
Do you get a WTS (wait to start) light?

 

No I do not, I get no idiot lights and the truck won't start. It has to be my PCM. This all happened the day I installed my power programmer. Come to find out the company sent me one for a manual transmission (my truck is not a manual). So I pulled the power programmer off and sent it back. Being the smart guy that I am, I did not disconnect my battery while installing the power programmer. Needless to say, my truck does not start now! Lesson learned!

 

You shouldn't have to disconnect the battery cables to do that as long as the key was off. Have you checked fuse number 22 under the hood?

 

Yep, probably the PCM. Just for grins check under hood fuse #22. It's a 30 amp maxi fuse and powers the PCM relay. If it's blown then you will get the symptoms you are describing.

 

Fuse looks fine, I replaced the PCM and still have the same symptoms! What else could be wrong? Relay?

 

Did you check the fuse with a multi meter or test light? Sometimes it is hard to tell whether the fuse is blown (although with these Max fuses it's usually fairly apparent). And yes there is a relay under the hood for the PCM. Just swap it with any of the others (the horn relay is a good one since it is easy to test - push the horn). They're all the same.

 

I replaced the fuse and relay with new ones and my truck still has all the same symptoms (no "WTS" light, no engines lights come on, and it won't start). The engine definitely cranks over like it would like to start, but nothing. What other possibilities before I take it to a shop?

 

The only thing I can suggest at this point is to check the wiring harness that goes into the back of the PCM where it sticks through the firewall. Make sure it is tight (there is a bolt that holds it into the PCM). Also check the red wire in that harness. It should get 12V with the key in the "run" position. If not, you have a wiring problem. If it does, then I am thinking that you have another bad PCM. You replaced the PCM with what? A new one? And you replaced the PCM and not the IDM right? IDM is on the fender under the hood, PCM sticks through the firewall from inside the cab.

 

Also, check if you have voltage at fuse 22 with the key in the run position. Wonder if you have a bad ignition switch?

 

Alright, thank you for all of your help. I will check all of that. I went to autozone and got a refurbished PCM. Lol, yes I am sure that it is the PCM that I replaced. Another thing, the ford dealership said it might not start after I install the new one cause it might need to be flashed. Is that true?

 

I always hate to ask a question like that but you never can tell the mechanical ability of the person on the other end of the internet, lol.

I don't think the new PCM should need to be flashed. I would think it would have a version flashed to it when you buy it. Did it have a version code on it when you bought it that matches one of the codes on the previous page?

There is also a diode in the circuit that supplies power to the PCM. You might check that as well while you have the DVOM out. If you don't have a DVOM with a diode setting on it, just check it for continuity. If it conducts, you're probably alright.

 

Check fuse #9 too. Fuse #22 supplies power to the PCM relay and fuse #9 is actual power to the PCM through its relay contacts. Either can cause the issue.

 

I know this is prolly a super rare occurance but I had a guy bring me a 95 with the same symptoms, no wts light, no start, no smoke. After swapping pcm and idm with good know ones i had nothing. All fuses were good, relays worked but the pcm would never get power. The glow plug regulator never clicked either, so for some odd reason I unhooked the EBP sensor and heard the gpr click. Turns out the EBPS was shorted out and was pulling the voltage down low enough that none of the sensor/relay circuits would work but wouldn't blow a fuse. It was very frustrating.


Again, prolly a super rare deal but worth a shot. Turn the key on and onhook one sensor at a time, see if anything changes.

 

Good point and troubleshooting tip. You are correct, if any of the sensors the use VREF or +5 volts from the PMC are shorted then the PCM is inoperative, I forgot that. IIRC the ones that use it are MAP, EBPS, ICP and BARO. CPS also uses it however truck won't start with it unplugged, however you should get dash idiot lights and GPR operation.

 

I thought I read on here the pcm's bought from the parts stores do have to be flashed. Maybe I'm wrong, but I swore I read that sometime..