Hello Folks

I hope someone can offer some insight to my issue, I bought a Frankenstein 1981 F-100 (so the vin number says) but its on a I believe F-250 chassis, it has 8 lug wheels. but anyways I'm all of a sudden having issues where i'll go out to start it and it will attempt to turn over and then nothing, or it will just have nothing, no click no trying to turn over etc. I replaced the battery, starter, Solenoid, regulator, and as of 10 minutes ago the positive battery cable. the negative is good and tight and connected to the starter housing. I'm getting 12.76 with it off and 14.56 running. I went this morning and it had nothing so I jumped it with the wifes car and I'm guessing I got it to start off her battery, I'm not sure seems kinda weird. pulled into the garage, shut it off and went to restart and nothing. ran to the auto part store for a new master cylinder and came back and now its starting. this happened a week ago and did the same jump start with cable thing and never had an issue until a week later, started every day just fine. Sorry for the long story but trying to give as much detail as possible. had the alt checked and seems fine I guess.

 

If I remember correctly , the starter relay is located on the fender well. With that in mind , the inner fender well has been exposed to a lot of opportunity to rust due to weather and moisture. I believe the starter relay uses the fender well metal for a ground . If that ground is not good the relay can't function as required. A quick confirmation would be to run a ground wire from the battery negative terminal directly to the mounting of the relay on the fender well. If that is the only problem, you will have solved it.

 

Thanks hanky for the response, the truck has been gone through as far as body parts from what I can tell there is almost no rust, I do see that the sheet metal screws are rusty and the inside of the fender where its mounted is painted not sure if its been wire wheeled away or not. I didn't pay attention when I replaced it, but this issue that I had last week is what led me to replace the relay and since it worked for a week I thought the issue was solved because when I changed it I noticed that the positive terminal on it twisted back and forth, so I assumed the contact inside might have broke. but I will definitely do the ground wire from the battery to the bracket. (A side note.) when it wont start at all as in completely dead I have checked the battery with a volt meter and it shows full charge. I just wished the guy I bought it from about 6 months ago when he started the home restoration he would have done the chassis instead of the cosmetics

 

The solenoid lugs coming loose isn't all that uncommon (more so if the cable is allowed to rotate when replaced) and most times you can just tighten the primary nut if it's just slightly loose.

So,, at the times it hasn't started, have you jumped the solenoid to see if it will crank? If an automatic, the strart circuit to the solenoid comes through the safety/range switch. And of coarse from the ignition, on down to the range switch. Manual would have clutch safety switch.. If it'll crank and start at the solenoid, but not with the key, work backwards checking for an active crank circuit.. Will it crank if attempted in neutral?