1985 chevy s10 starter engages

It cant engage unless its getting power, so that would tend to suggest a short between a hot wire and the solenoid energize terminal. Very slim possablity of an issue with the ignition switch. More info may be helpfull, such as which engine,. the 1.9 Isuzu, the 2.2 dieseal, the 2.5 iron duke, or the 2.8 V-6. On the V-6 the harness to the starter runs close to the exhaust manifold, and can get too close to it resulting in melted insolation. The 1.9 starters were probmatic, but it would be a stretch to have three do the same thing back to back. also what Tranny? Automatic could posibly be a short in the wiring around the nuetral safety/reverse light switch. although the safety side only has power when the key is in the start position, the reverse light side has a wire hot all the time.

Whitelightning

starter, because while traveling it would engage at

It's a 2.8 v6. so the harness next to the exhaust manifold melts and the bare wire short. This bare wire is back from the starter next to the exhaust manifold, correct?

Did you swap out the solenoid from the old starter? I had the same thing on my 85 S-10 4x4, turned out to be a broken spring for the solenoid return inside. If you did swap it out you should have seen it. If not the replacement may have a broken one.

GM

I didn't do the work myself. I bought a rebuild 1st and they put it in and it failed a day later. Then I bought a new one from autozone and that one is intermittant. The solneoid is part of the start when you replace it correct??

thx for your input

The solenoid sits on top of the starter. It is where the battery cable bolts to along with the ign circuit. I believe that you can get a starter from AutoZone either with or without a solenoid. If it truly is not an electrical short ( another posted about the wires close to the exhaust and if you move brittle wires around you will get a short) that would cause it to engage there are very few things were it will engage by itself. The big spring inside is designed to kick the bendix back when the circuit is de energized. This then holds spring pressure against the bendix to keep it disengaged. If the spring breaks then it would just either vibrate or if you hit a hole or something could cause it to bump against the flywheel. The solenoid is nothing but a big electromagnet that overcomes the spring pressure and drives the bendix forward into the flywheel. I may be off a little on the explanation but that is very close. GM

So a good test for the short is moving the harness around with long screw driver. The rebuild included the soleniod. The explaination you gave above is the extra symptom for the initial failure. I hit enough bumps and the dam thing would engage intermitantly. The first replacement failed completely just engaged and burnt out. The second one was a new one, but it hasn't failed completely and isn't engaging as per this post. But the Midas mechanic said it was doing it after he changed it and blamed it on clutch failing and wants to replace the flywheel and clutch. I just towed it home and this is the first chance I've had to try and figure it out.

If it is an electrical short then I would start at the starter and trace the wires back. Look closely at places close to heat sources, wire loom attachments, etc. Moving them may re create the conditions that causes the short. The short would have to be in the ign circuit wiring (the very small diameter as compared to the battery cable sized on the starter) as there is power on the large circuit all the time from the battery to the solenoid. When you turn the ign key past the normal run position you are completing the circuit on the ign wire on the solenoid and that's why it engages. Let go of the key and this is circuit is de energized. So, if it is electrical move it, wiggle it bump it etc. The vehicle does not need to be running. Just have the key in the normal engine running position without the engine actually running (I hope this makes sense) so all the normally energized circuits are hot. Electrical troubleshooting is a real pain in the a$$ sometimes. When I replace the starter on my blazer I ended up replacing the ign wire back up to the top of the wire loom. The wire was really brittle and the insulation had cracks all the way through. The area gets so much heat that the rubber water splash shield from the inner fender was heat cracked and brittle. I just ended up taking it off. Probably not good in the long run as water from the wheel well now splashes over into the engine compartment. I have no idea how the "Midas" man can blame the clutch failing as the reason the starter engages. That is a new one on me. Maybe someone else can tie that one together?

GM

there's a small wire on your starters solenoid its connected to the "S" terminal look for any possible way for battery voltage to travel this circuit. (melted insulation, two wires melted together ect..) Also once I worked on a car that did this, the cause was the tilt steering wheel, the bolts had loosened up so much that when you pushed up on the wheel some times it would crank the engine.