Hey Fellas; Got a 94 Z28 project car for real cheap and am having trouble starting it.
It has 117,000 miles and previous maintenance is unknown.

Had to replace the Bendix drive on the starter to get to this point; but when trying to start, the motor will crank and then once you let go of the key the motor will kick back.

Hopefully it hasn't destroyed a rod or valve yet, but what exactly would be the cause or things I can check.

Would the Optispark cause this condition?
Or does it looked like it jumped timing?

Appreciate any help.

 

Could have a cylinder filled with water or plug wires on wrong or just about anything, since you have no idea of previous work or condition.

 

I'll check the plug wires again tonight and a few more tests that's on your site.

I tested the ICM and had Advance test it also and it come back good.
Primary and Secondary on the coil was high. Can't remember primary but secondary was at 9300.

I also tested the harness going to the optispark
a= 5v
b= 5v
c= 12v
d= 136 ohms with key on and 3.3 with key off.

I'll test some more this evening and double check last nights results.

Thanks for the reply.

 

If it can't even complete a revolution, I would be pulling plugs. Since the starter was already broken, it makes me think the scenario of a filled cylinder is a possibility. You can easily bend a rod in that situation.

 

That's why I haven't tried to start it anymore.
It would keep making revolutions, but once you let up it would spin back to where it started and clunk and bang. I would say the damage is already done, but I'm hoping not. Timing is off bad or like you said a cylinder is full. Gotta work today, but I'll try to pull the plugs this evening or tomorrow.

 

If it is continually turning over (which was not clear to me before), then it won't have a cylinder filled with coolant or fuel. Check the plug wire routing.

 

Checked plug wires last night and it is good according to the Haynes manual.
If I pull the ignition fuse it will continue to turn over and not kick back when the key is released.

So something in the ignition or timing is off. I wish it wasn't a 94 so I could read the codes. I may put a post on a local board to see if anyone has a reader and can check them for me.

 

Maybe you can use this:

https://www.camaroz28.com/forums/lt1...bs-srs-874325/

 

Saw that. Think the cable is $60 online to connect to computer. Trying to stay as cheap as possible right now, because for the price of the car I paid; I can part it out and then junk it and make some decent money off of it.
If I could just get it running first, I wouldn't care to invest in a few things.
Thanks.

 

An Opti that isn't indexed correctly could cause the problem. Did the previous owner replace it recently? A rotor the has come loose but is still turning could cause the problem.

This assumes it has not started or run since you bought it . Was it running for the previous owner?

 

Found out what the problem was.
Seen a wire hanging from under the steering column so I pulled the panel off and saw a black box. Researched it on the net and it's an aftermarket security system. Unplugged all the connectors and she fired right up. Can't believe it was something so simple.
Thanks for all the replies. Appreciate the help. I'll get her cleaned up and post some pics when she's done.

 

Glad you found the problem. If you're in Louisville, I can scan the car.

 

You and me both. Live in Ashland; so that's a little far, but I do appreciate the offer.