u3071844

I recently was given a 1992 f150 from my aunt. It has been sitting around her farm for almost 10 years. I am not a great mechanic, but I can remove and replace basic parts and do a little troubleshooting. I have had the truck for about a month and finally got the engine to crank after replacing both fuel tanks, fuel pumps, fuel tank switch, TPS, and some minor engine work. The truck cranks fine, but the voltage guage fluctuates between 14-16 volts. The engine RPMs also fluctuate up and down with the volts. I do not have a tach, so I'm not really sure what exactly the RPMs are. I do know they fluctuate together though. I pulled the alternator and had it checked at the parts store. They said it was bad so I have a brand new alternator installed and the problem is still there.

I also have a CEL on constantly. I bought an OBD1 code reader but the code reader will not link to my trucks computer for some reason. I know the code reader works because I pulled codes on my friends 94 model ford truck and it worked fine. I also tried the paperclip method on mine with no luck. No CEL flashes or anything. It's like the EEC harness is not even connected to the computer or something??? I tried both ways (KOEO and KOER)

I really need some advice. I'm pulling my hair out!

sylver91

If you can't get codes, chances are the computer is bad.

u3071844

How can I check it. Everything else seems to be working fine. Could it possibly be a loose ground (I think I checked them all) or a bad wire?

Also, would the fluctuating idle and voltage probably be caused by fuel, electrical, or emmissions?