I'm trying to get this beast back on the road. 1976 f250 ranger 460. I hooked up the battery and went ton start it. The starter kept turning, even after I took the key out of the ignition. Now, everytime I put the negative terminal on, it tries starting by itself. Any ideas?

 

Welcome to FTE One thing you might look at is the solenoid. Be sure any replacement is a genuine Motorcraft, or at least something made before 1980. The drugstore el-cheapos aren't built heavy enough and are prone to this, and won't have saved any money. Charge the battery up thoroughly maybe think about replacing ground and start cables as routine. The idea is to have minimum resistance and voltage drop in the start circuit.

 

Could either be the solenoid, starter switch or the wiring inbetween the two or the starter itself. Disconnect the cable from the starter then use a multimeter at that end of the starter cable and see if you have voltage.....with the battery hooked up......if you do....its in the switch, solenoid or wiring......NOT the starter.

 

Disconnect the NEG battery terminal. Whack the solenoid a few times with the handle of a screwdriver. Re-connect the NEG battery terminal and watch for a spark or sparks from it.

No sparks there? Start 'er up. Still have a spark or two when re-connecting the NEG and still wants to turn the starter? Pull the S terminal wire from the solenoid and let us know the results.

 

I've had several starter solenoids bad out of the box. But they were LMC, AutoZone or O'Reilly. Spend the extra bucks for the MotorCraft. Sometimes you can find NOS at a Ford store or on eBay. Never hurts to have an extra, either.

My LMC solenoid dead-shorted through its' body. An o'reilly kept turning the starter even after the key was released. The top of an autozone broke right off during installation.

I run only Ford solenoids now.

 

X2 on I bet you have a bad (stuck/internally welded) starter solonoind. The one mounted on the passenger side inner fenderwell. You can try the wack it trick, I would just replace it with a quality one.

 

Upgrade for the Starter Relay/Solenoid from a newer truck fixes this and other issues.

Doesn't look factory or original but works reliably.
Napa Echlin ST404 https://www.napaonline.com/napa/en/p/ECHST404/

 

Could just be the solenoid, but mine was doing this, and although I replaced the solenoid at the same time, I also replaced the missing ground between my engine and my cab, and the starter has never hung up since.

 

UPDATE: Turns out the issue was from the starter solenoid. I did disconnect the negative battery cable, as this was the only way to stop the starter. (the key was off and out of the ignition) When I reconnected the negative battery terminal cable it was sparking. The starter would automatically try starting again on its own. I whacked the starter solenoid a few times and it stopped. The real issue was that the Starter Solenoid was not bolted down all the way. It was an improper ground. I had to run down to the local auto parts store and buy some slightly bigger bolts to hold it firmly in place. Bam! No issues. Thanks for all of your help.

 

That'll do it. Thanks for updating everyone on the fix.

 

Thanks for the follow up. FYI It is wise to always have a wrench in the glove box that fits the + side battery terminal bolt.

 

You mis-spelled negative!

 

Hey guys, I found this thread in a search for this problem, same happened to me yesterday, I've been doing a google search for a Motorcraft Starter Solenoid and I'm having no luck finding one for a '79 F150, where do you find yours ?

 

https://www.ebay.com/itm/172610792692

 

Junkyards.