Hello,

I have a 1991 F250 and the starter needed to be replaced because the gear arm wouldn't engage.

I put a new starter in, cranked it a couple times, and it started fine. On the new starter was a sticker that said it was highly recommended to replace the solenoid as well, so I did that.

After putting on the new solenoid, I started it, but the starter would not disengage, it just kept cranking and cranking. I had to run and grab a wrench and disconnect one of the battery terminals to get it to stop.

I looked at the solenoid, and noticed my negative battery terminal cable was touching the bottom post on the solenoid, so I fixed that, started it, and it worked fine. I drove it for 2 weeks with no starting problems at all.

Then one day I started it, and the starter wouldn't disengage again. Had to run and grab another wrench and pull a terminal off. I had a friend drive me back to my house and I grabbed the old solenoid and put it back on. It started just fine after this and I got it home.

A couple days later I went out and tried to start it, turned the key, heard some clicking and a low groaning noise but it wouldn't crank at all. Tried it a few more times, same results. I assumed the batter was dead since I almost ran it all the way down from the previous time the starter would not disengage. I charged the battery for a day, went out and tried again. Turned the key 3 times, and nothing, but this time I noticed that the positive battery terminal was smoking each time I tried to start it but it wouldn't crank. Finally on the 4th time it started, but the starter wouldn't disengage again.

So I run and grab a wrench (you'd think I'd be smart enough to have one in the truck by now) and take a battery terminal off and let it sit for a minute. I try and put the cable back on the terminal, but the truck starts cranking. The key is out of the truck, but the thing tries to start just by putting the battery cable back on.

So I run back to the parts store and tell them what's going on They suggest bringing the new starter back in so they can test it, which I do. The test says the starter is just fine, but they give me a completely new starter just in case. (Thanks Checkers) I put the new starter in, put the truck in neutral (almost ran over my foot the last time when the thing tried to start) and touch the battery cable to the terminal, same thing, it tries to start with no key.

So today I did 3 thrings. First, I did an ohm test on the solenoid with no wires connected to it, and it gave a reading. So I put the new solenoid back on. After this I put the cable back onto the battery terminal with no issues.

I also bought a new starter ignition switch and installed it thinking the spring in there could be bad. I got that put in, put the battery cable back on the terminal (took it off while installing switch) and gave it a try. It cranked just fine. Turned key off and back on 3 times, worked fine. (It wouldn't start because I had the fuel tank selector unplugged from getting under the dash)

I plugged the fuel selector back in, and tried again. Nothing, just the positive battery terminal started smoking again. Tried a few times, same results, wouldn't crank, and just more smoke.

I'm at a loss here as I can't think of anything else to look for. Hopefully somebody out there can suggest a next step to try and get this fixed?

Thanks!

 

First of all let me say I have experienced this on two Fords, a 1988 F-150 and a 1990 Taurus. When mine would keep cranking, I would jump out, open the hood and first unplug that little slip on wire on the solenoid, effectively disconnecting the power from the switch that didn't stop it so I knew it wasn't a bad switch. Next I gave the solenoid a few karate chops and that released the solenoid, so I knew I had a bad solenoid. Yours couldn't be a bad starter(s), because the starter has to get the power to crank from somewhere, it won't just crank by magic. At this point on yours, I would try another new solenoid, it sounds like the power is not getting to the starter and shorting out somewhere at the solenoid. That first new solenoid you bought was definitely defective. Keep us posted. Good luck.

 

Quick question. Should I be getting an ohm reading between the two solenoid main terminal posts with the key off? That would mean I have a short somewhere correct? (There is no ohm resistance when the wires are not connect to the two posts)

 

I'm not too much into ohms and test meters, I think more along the lines of the principle of how something works. Here's a test I would try: take something like a large(big around) screwdriver and short between the two large solenoid terminals and see if the starter will crank over. This with all connections hooked up and tight. You will need to use something large enough to carry the full current when you short the two large solenoid terminals together. This will effectively bypass the solenoid and run the current directly from the battery to the starter. This will get you started in the troubleshooting process.

 

I put in a new solenoid again today, same results, negative battery terminal just smokes when I turn the key.

I undid the wire on the solenoid that goes down to the starter, no smoke.

Is it possible my battery is bad and is shorting out when a heavy load is applied? Any other ideas on what to try?

 

I don't think it's your battery. Is your battery pretty well charged up? I am guessing your starter may actually be bad now, assuming the wire that goes down to the starter is hooked up correctly and there are no spots where the insulation is off and it's grounding out.

 

Yes, the battery is putting off a full 12v.

I already replaced the first new starter I purchased, so this is the second new one.

The wire going to the starter looks fine.

 

Yes, I realize you already swapped out your starter, but there was probably nothing wrong with the first one you purchased. That being said, sometimes rebuilt starters are not that great. All that being said, I would only know two things to try: either take the starter off and have it tested OR get a battery cable long enough to run from the NEGATIVE battery post to one of the starter MOUNTING BOLTS to serve as a temporary ground for testing.