Ok, I'm at a loss to figure this one.

Problem: New starter will fire whenever key is set to start, even with engine running.

Backstory: 91 Z28, 305 - originally a T5, previous owner converted it to an Automatic 700R4.

My starter started clicking instead of turning every once in a while so i decided better replace it before it's too late. Bought a reman starter for the 91z auto and brought it home - didn't line up right. So i brought it back to Kragen and brought the original with me. The parts guy noticed that the original had "Marine" stamped on it and asked where the trans came from that would have that starter. I don't know anything about where the current 700r4 on the car came from. After looking through parts books for a while and bringing up a few other starters nothing looked similar to the one i had. Then he had a bright light and asked if i had a lot of room around the starter, i said 'yup' and he gave me a much larger starter that lined up with the one i had - he said it was the standard model found on many GM cars. It was new and fit on the car perfectly so i had no complaints (other than i had to drop the front of the exhaust to get it in - doh!). Shimmed it up properly and wired it as the original was.

So the thing starts OK but whenever the key is set to start, the starter will run but makes that unmistakeable 'my car sucks' grinding sound if i hold it too long. The 'safety' won't kick on when the motor is running. The other starter didn't have this problem and I've triple checked the wires for accidental grounding. I've got 3 large primary wires on the P and the small purple wire on the S. Neutral safety switch appears to be working normally.

What's up here?

 

I dont think any of the thirdgens had the hey dumb *** its already running safety.

 

OK good to hear it. i was just thinking maybe i just never noticed it before. So then the problem remains that at the end of the 'start' cycle i can't let the key go fast enough before it grinds on the flywheel. Would that be a shim issue? I used the 1/8" spacing rod they gave to measure between the starter shaft and the trans flywheel (although on their diagram it was a small flywheel gear) and shimmed it until it was just snug but it still makes noise when the enigine catches. I experimented with a few different spacings, further and closer to the flywheel, and didn't notice any different. Did i get the wrong instructions or something?

 

The only thing i can think of is that your holding the key in the start position to long or the momentary switch is getting weak.

 

Momentary switch? Don't know that one. Is that on the solenoid or the ignition? Did a search and couldn't find it..

 

Momentery switch is a switch that releases when pressure is released like on an ignition key switch or a nitrous button.

 

yes it is in the ignition switch, mounted on the steering column, notice how when u turn the key to start and let go it returns to run? well that is so the starter is only activated while u hold it to start, it shouldnt keep going after u release it

 

Ahhh, IC. It sounds like the starter is grinding as the engine starts up and it winds down. I can't imagine it's a problem with momentary switch as it has plenty of "spring" and things were working fine in regards to that with the old starter. I'll try to re-shim it AGAIN although i know i tried 4-5 different distances using the 1/8 tool as described. I'll try to us the paper clip method although i remember when i tried it i couldn't coax the starter gear to the front of the nose to take the measurement; there just wasn't enough room to get a small screwdriver in there. didn't see any access holes on the bottom either.. Any tips on that?

 

This ended up indeed being a shim problem. Apparently the instructions I got with the shim kit from Kragen were off - they said to use the 1/8" to measure the distance between the starter shaft and the flywheel - after experimenting I found that the correct spacing for this application is to use the tool to measure the distance between the COLLAR at the end of the starter shaft and the flyweel. That meant changing things a lot - i ended up using all 3 shims (on both sides) to move the starter farther out.

With this particular starter, there was not enough clearance (or access hole) to extend the starter gear in order to check using the paperclip method.

Thanks!