Electrical Problems, bout to give up


Active Member
Jun 12, 2005
Perhaps the title is a little dramatic, but I am at my wits end.
I am doing the old 4cyl to 8cyl conversion on an 86 fox body.
Most everything is done I am just tidying everything up and trying to make the last few modifications.
I have had the engine running in the past in this car but every once in a while I would go to start it and it would continue cranking even after it’s started. The solenoid gets stuck and the juice stays flowing to the starter. In this case I have replaced the solenoid. Recently it did this with a brand new solenoid at the first crank.

I had a ****ty battery which was on its way out and so I replaced it with a bigger battery and also mounted it in the trunk. As soon as I tried to crank it over it would barely crank and the brand new solenoid got stuck again. My best guess is that there’s a short somewhere in the endless wires or I have one connected where it shouldn't be. Any guidance or suggestions would be appreciated,
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For one thing you need to make sure the grounds are good and tight. Make sure you have a good ground on the back of the engine to the firewall one from the battery to the chassis and these locations are free of paint. Use 0 gauge wire from the front to the back of the car. Make sure its secured to the chassis with rubber clamps so it will not rub. If you are using a minu started use a solnoid from a 92 and up stang instead of the old clunker engines.
Here's a diagram of the starting system for an 86 5.0. Check to see if you have power on circuit #32. It should stop cranking when you remove power from that circuit. If it keeps cranking the solenoid is sticking.. If it stops cranking the solenoid is operating as designed.
If you have a poor ground connection the solinoid circuit could be seeking gound by any means keeping enough current flowing to hold the solinoid closed.. the way you see tail lights on a car light weakly when the brakes are applied when the brake circuit has a poor ground.

One way to test this is when it runs on pull the #32 wire and see if it stops.
Used 11ft of 2 gauge wire, but remember it was doing all this before I transfered the batt. so I doubt this is the problem.
Thanks for the help guys I'll get working on it first thing in the morning and let you know how I make out.
Motorcraft solenoid might be a good thing to get first.
thanks again
Wow cant thank you guys enough,
Hooked up all my grounds and works perfictly:nice: :hail2:
I guess this means I have about 5 solenoids sitting around that are perfictly fine, lol....
Unfortunatly my starter seems to be spinning without hitting the flywheel so it looks like I need to replace that now:bs: ... but at least its not an electrical issue, bolts I can deal with.:nonono:
working fine now thanks
new issue arised though, making new topic

no that is what i am talking about, is it grinding or just spinning. sometimes mine comes loose and grinds. if it just spins. remove the wires,2 bolts and replace starter, no need for another post. in case you haven't made one yet anyway.