OK, so I have been working on this 83 z28 for a while now. I've done a lot to it, 383 stroker engine, TKO 600 trans (originally a t5), ripped out old gauge cluster for Autometer gauges, plus a ton of other stuff that I don't think is related to the problem but I cannot get this thing to fire up when cranking it over with the key. There is no spark according to my timing light. However, if I leave the key in the run position and hit a button wired directly to the starter it fires right up. So I am at a loss. I don't know if there is something related to the removal of the original cluster or the trans, however I don't believe the trans has anything to do with it. There were two wires coming from the trans, VSS and reverse from what I recall. I'm thinking this may be related to the cluster removal? I'm not sure. Anyone have any thoughts? Never an alarm in the car.

 

Standard vacuum advance hei distributor? Is the power lead to the distributor losing power when the key is in crank? Possible ign switch issue. Not the key switch, ign switch down farther on the column.

 

Not exactly what I wanted to hear or deal with...

 

Actually, the ignition switch on these is a LOT easier than many other vehicles. No need to even touch the steering wheel or key lock cylinder (other than for trying out the new switch adjustment).

 

Could be the ign switch but...

If the PO "improved" the car by wiring the dist to "a wire that was hot in Run", instead of THE RIGHT ONE, s/he may have chosen one that was that, but not also hot in Start.

Friend of mine did that to an early 60s truck he had, about 45 yrs ago... to start it you had to whirl the engine, then let go and tap the gas. It would start if you did all that while the motor was coasting to a stop. Turned out he had "found" a wire that was part of an under-dash aftermarket AC that some PO had added and then ripped out, leaving a bird's nest of copper wool. He sold it to a mutual friend, who just couldn't master the technique. Wiring it correctly solved it instantly.

Check what the dist is ACTUALLY powered from.

 

Well, the thing is the car fired up as normal when I parked it in the garage roughly 5 years ago to start the transition to aftermarket gauges, new trans, subframe connectors, sumped fuel system, etc. I didn't really touch the wiring except for the gauges, which is why I thought the gauge cluster removal may have started the issue.

 

I had this problem on my 73 Camaro when I got it. It wouldn't start no matter how long I cranked it. But sometimes it would start after I let off the key while the engine was still freewheeling. IT was frustrating since, I assumed, it was all connected properly. Since the car was originally points ignition a PO had hooked up to a hot in ignition wire when they put in the HEI. The points power was a resistive wire from the factory. and the wire they chose was not hot in start

We wound up putting in a relay that connected to the other terminal on the starter, which is for points ignition (?), so that the relay would have power while the ignition switch was in start. The on/off time of the relay wasn't noticeable and I was able to get the car to start immediately consistently after the relay was installed.

 

So I took apart the ignition switch and cleaned up all the connections, replaced the dielectric grease and put it back together... still nothing. Can anyone tell me what all the wires do that go to the switch? I could only find part of the schematic which has two power wires and a starter wire but I pulled two harnesses off it with a total of 6 wires. Obviously something is making the correct contact in the thing when it has no issue turning over... Is there a coil wire on the thing?

 

OK, so I took a look under the hood again because (and I don't know why it matters being that it never did before), there is a large gauge pink wire going to nothing near the distributor. Now the distributor is a MSD pro billet 85551 going to an MSD Digital 6 plus. I just realized that it turns off when I crank the engine over with the key and it doesn't do that when the engine is in run and I crank it over with the button connected to the starter. Thoughts? I swear I never changed any of the wiring. Could it still be the ignition switch?

 

ok, found the problem, whichever accessory I had the Digital 6 plus hooked up to no longer was powered when I was cranking it over. I hooked it up to the large gauge pink wire that was next to the distributor (which is probably where it should have been from the get go) and it fired up. So strange that the accessory I was using decided to turn off during cranking. I'm just glad I found the issue even though it took way too much time to do it...

Thanks everyone for the help.

 

Not all ignition sources are hot during cranking, or start. There are only a few circuits that are hot during start, the ignition coil, the gauges and the starter are all I can think of off the top of my head (besides anything engine related).

Is your gauges fuse blown? The gauges fuse powers some of the emissions equipment in the engine compartmen. If you connected to that circuit and the fuse blew that would cause your issue

 

That makes sense because I pulled the stock gauge cluster and built my own only tapping into the wires I needed. So if the cluster was connected to some of the engine harness wiring and I'm no longer connected to that then that would explain it. I had a feeling it had something to do with the cluster...

 

Exactly.

The large pink wire is the original 12V source to the dist, and as such, is the exact right place to connect distributor-related things to.

Glad you found it and thanks for letting us know what the solution was.