1991 300-6 which has sat for less than a year while working on other projects. Has sat outside which is the first problem. The engine was just rebuilt some 20,000 miles ago. So here is the story and ill try to keep it short. NO spark at all.. nothing at the coil changed the ICM. But after reading through my trusty Haynes manual it says something about the fuel pump turning on when the ignition is first turned to run. Thinking back when i drove the truck i remember it doing so and now it doesn't/ So the manual says that the EEC-IV PCM isnt getting power and my question is im not to sure about digging into all this electrical stuff and really want to know what im getting my self into trying to get this bug out. So any sort of direction to get some power to the EEC-IV PCM and anything that is common that happens to these trucks after sitting. Any help what-so-ever would be appreciated..
Thank you and take care
Brian

 

I don't know specifically, but my first bet with it sitting that long would be that the battery is low/dead and/or the battery cables are bad. Also, have you tried pulling the codes? I'm just asking because it sounds like you only have an indirect determination that the PCM is not getting power---- but if you hook it up and you get codes then you know obviously it is and there is something else causing the problems. Plus, if you get codes it might point you in the right direction for a fix. If there's no power at all to the pcm then I'd look for any disconnected/corroded connectors in all the wiring harnesses.

I guess what I'm trying to say is to check/doublecheck the easy stuff while you wait for one of the more knowledgeable people here to answer.


Edit: might want to also check the ignition switch.

 

Depends on where you live, too. If it sat outside, and there is any wildlife around, critters may have gotten in the engine compartment and chewed a wire somewhere. That happened to me on an old Ford van I had. Chipmunks made a nest under the air cleaner and the wires to the coil were chewed through.

 

Battery is fine because we are using a different battery than what was in it. Battery was taken out when we parked it. Thanks for the information and see what i find today when working on it. And does the PCM have a direct hot wire that feeds it or is there a round about way that it gets its power. Thanks Take care
Brian

 

thanks to those people who gave some suggestions. After working on it last night i got it running again. Take care
Brian

 

And you fixed it by doing???

 

i would have explained how i fixed it but its really hard to explain. The jist of it was checking for power in all the main locations and rechecking everything. Finds out a wire was hot on one side of the plug and not the other. Noticed this by just feeling the wires and one was warmer than the other. so i just hot wired it, fuel pump kicked on when i turned the key like it should and fired right up. Nothing but a smooth running 4.9 to make a day seem a little better. Sorry for the late post havent been online in a very long time.