Bozso

Several weeks ago my 1981 wouldn't start. Bench-tested starter and found it was bad. Replaced with rebuilt starter/solenoid, connected wires exactly as previous one was wired and car started great - 3 times. On the third start, engine stayed running with starter engaged when I turned ignition off and removed the key. I revved engine and re-inserted key to stop engine as I was in a bit of shock, having never experienced this before. Of course that didn't work so I immediately moved to the negative cable and disconnected from battery to kill the engine. I focused on ignition switch, testing ignition wire (disconnected from solenoid) for power in each key position to find 12+V in both the start and run positions. I replaced the ignition switch (twice) only to show the same voltage. Ignition switch ruled out (also ruled out possible key lock cylinder and actuator rod as I activated switch with screw driver during some testing). Also ruled out neutral safety switch as this cuts power to solenoid when car is not in park. This leads me to a sudden wiring issue between the ignition to solenoid wire and the ignition to coil wire and/or accessory. Lots of wires are taped, wrapped, etc.
Is there an obvious place to look initially that is problematic? Or do I have to tear apart wiring starting at one end? Considering fuse box removal next.

billschroeder5842

I have an 82 so we are very similar....

I pulled out my wire diagram and found that you need to check the following (not in order)

1) fusible link
2) crank fuse in the fuse box
3) Theft deterrent starter solenoid
4) Neutral safety switch

I ran the possible wire routes and came up with this.

My guess is that you have a grounding issue and your spinning starter has become that ground. If it were me I'd start with the fusible line and the theft deterrent system IF you are sure your steering column is good as in fully grounded.

Sorry, electrical sucks especially on a holiday weekend.

AzMotorhead

Make sur eits not the gear just hanging up on the flywheel( not enough clearance between gears) drop starter off the block & if you can leave wires attached. Hold the starter so it wont move then have another person hit the key. see if starter functions as it should or if it stays running once key is released.
I'm betting you have a bad starter or one of your hot leads is installed incorrectly(touching another post.)

Bozso

I have the ignition (neutral safety switch) connected to the small post and the big, positive cable from the battery plus 2 fusible link accessory wires connected to the big post. All cables/leads are clearly no where near the other posts. Even with ignition wire disconnected from solenoid, hanging at bottom of car with my voltmeter attached I get 12.5 volts in both crank and on position. This can't be right. Some where some how the ignition to solenoid wire is getting 12V in the ON position when power should be cut to the solenoid. Where is this power coming from?

TimAT

1981 has a starter extension harness on the firewall just right of the distributor. They have been known to melt and short.

Bozso

Would you have a picture of the one you're referring to? I found only one harness from the starter, about 1.5 feet above the starter, then direct wiring from there to the fuse box, which looks fine - no apparent melting or wires making contact with each other.

I did detach the fuse box, tons of gunk and crud on the big, engine-side harness that plugs into the backside of the box, coating the prong-ends of the wires. Cleaned that up best I could.

Considering this whole issue started between literal engine starts just seconds apart I'm expecting something very simple.

Bozso

I'm not familiar with the theft deterrent system (not really sure '81 has one) but don't think a ground problem results in 12V registering at the solenoid in both start and run. Even without the ignition to solenoid wire disconnected, thus taking the starter out of the equation, power is here when it should be shut down.
Plan on pulling all wires from Solenoid tomorrow and following to fuse block (except battery positive).

TimAT

If you follow the wires from the starter, the connector is on the firewall just outboard to the right of the distributor.


http://www.corvetteamerica.com/cf/di...ategoryid=x980

Bozso

Update: With everything re-connected and still getting 12+V at the solenoid in the Run key position (starter NOT cranking) I started the car and everything is running fine ... for now. With the voltage still being the same in both Start and Run positions there's something I'm missing. Guessing that if this is "normal" that the engine continuing to run after removing the key reflects an occasional sticking solenoid. If it happens again, starter/solenoid is going back as an exchange.
Thanks to all for replying.

sparky77

Did you shim the starter when you installed the new one ,Chevy starters need to be fitted to the starter ring in the bell housing.If not right the starter might get stuck in the on position.

Bozso

I was advised to not shim the starter by multiple sources. I can understand that the pinion could get stuck and engine continues turning the starter. But what keeps the engine running then if the key is removed from the ignition? I'd lean more towards the solenoid being stuck. There's no funky sound, grinding or anything else coming from the starter. I did watch several videos on how to shim the starter and it seems like a guessing game, so I opted for not shimming it at this point.