Replaced the oil pump on my 88 iroc on the weekend.Went to start the car and it fired up right away but the starter did not disenguage.Grinding away I tried to turn off the car but it kept on running with the key in the off position,Had to disconnect the battery to turn it off'Anybody ever have this happen before?

 

Have you inspected the starter for things like loose mounting bolts or broken return spring?

 

Yup. Sounds like you have the starter solenoid that's compatible with points type distributors, that includes the "R" terminal; and something is touching it or hooked up to that terminal. Starters don't need that terminal on engine w electronic ignition, so it's becoming less common, but there's plenty that still include it. The only ones that should have wires on them are the main post, which should have acoupla fusible links in addition to the batt cable; and the S terminal, which is the small one closer to the block.

 

And then there is the ignition switch itself, which is located nowhere near the starter nor the ignition key lock cylinder. Tilt columns and their linkages have been known to do some strange things at times. If the starter (most probable) is not at fault, checking the switch could be a next step.

Worst of all would be that within the scope of the work performed, something happened to the wire harness and it is turning the SBC into an SCR.

 

Nothing is touching the R terminal unless it is inside the solenoid.Purple wire is connected to the S terminal.Going to get a starter on the weekend and put it in and see what happens.Will update.

 

I got a starter from AutoZone that did the same thing. It was brand-new (not remanufactured) and I had to disconnect the battery to make it stop cranking. Everything was properly connected. I took it back and got another one, and haven't had that problem since...

 

Replaced starter/solenoid on the weekend and it fired up without any issues.Thanks Sofa.