Slayer

This week, I replaced the Opti on my 1993 Z28 (again). I got everything back together and attempted to start the car, but it just cranks and won't start. I double checked everything, and everything is connected except for this lone connector I can't find a home for. It splits off from a wire loom that comes out of the driver's side firewall, and it's purple with two red wires and one black wire. Does anyone have any idea where it goes? I'm stumped because I pulled the car apart a couple weeks ago, and I can't remember if I disconnected it when I pulled everything apart.

Injuneer

Could be for the AIR pump, factory wiring diagram shows one black and two red wires to a 3-pin connector. Would not prevent the engine from starting.

What brand Opti? Did you index the splined drive shaft correctly to the cam sprocket?

Slayer

I was tired of the Delphi and Delco Optis rusting on me, so I just went with a Carquest Opti this time because I used to work at Advance Auto, so I got a discount. Yeah, I got the splined shaft lined up so the "flat" spot slipped right into the sprocket. The car's sat for a couple weeks, so I guess I'll pull the battery and test it tomorrow at Advance. Sounds like a dumb idea, but sometimes, the simple ideas are the solutions. If that doesn't work, I guess I'll have to pull everything apart yet again.

Slayer

Perhaps the ignition coil is bad, too?

bw_hunter

https://www.camaroz28.com/forums/lt1...d-opti-601565/

Sometimes they're bad right from the factory...

Fatdog2

I'm following the wire bundle coming out of the firewall and I see one set of wires from the loom going to the dash under the windshield washer,then the next one going down under the fender I guess for the wheel or something,then the next bundle (3) plugs going to the abs box,then another plug going to the air pump.Hope this helps.

Slayer

Thanks for the responses. Here's a quick update. Before I read the responses, I changed the ignition coil, and the car still wouldn't start. So far, every voltage and ohm reading has come back normal on the ICM connector and the Opti harness. The only test left is "B" on the ICM connector while my girlfriend is cranking the car. If it comes back normal, then it sounds like I get to rip everything off yet again because the Opti was bad right out of the box. I really wish it was something other than the Opti because I'm not in the mood to tear about all the work I just put back together.

GaryDoug

By now you may have guessed that you don't have to put it all back together to see if it will start. Just don't run it more than a few minutes without a water pump or belt installed.

Slayer

I wish I had known that, but I assumed a new part would, you know, work.

One more question. If I remove the coil wire from the Opti, will that wire spark while cranking the car? I tried that the other night, and it didn't spark, but when I left the coil wire connected to the Opti and unhooked it from the coil, the coil did spark while cranking the car.

GaryDoug

I'm not quite sure what you are asking. But the spark comes from the coil to the Opti cap, which serves to simply route/distribute the spark to the correct spark plug. Hence the name "distributor". The Opti does not generate the high voltage "spark".

rngilliland

Was the car running before you replaced the Opti? Have you checked for any codes? You can flash them on a 93 if you don't have a scan tool. Check a spark plug wire to see if you are getting a spark. If you are getting a spark at a plug then you know you are getting one at the coil. Have you checked the fuel pressure or the injectors? If you have spark, fuel and air, and the engine still won't start, its likely that the Opti is indexed wrong.

Slayer

Yeah, the car ran fine before two weeks ago when I started it, and it immediately flashed code 36 and wouldn't restart. I just checked the computer for any codes, and I don't have any. I'm getting spark at the coil and I pulled the number 7 plug wire, and I'm getting spark at the cylinders. I need to check fuel pressure, but I'm assuming it will be fine. The Opti harness and ICM harness passed all their VDC, ohm, and VAC tests, too. I know the "key" is lined up with the cam gear because I didn't force on the Opti; it slipped on and sat flush with the timing chain cover.

Injuneer

When the starter cranks the engine, is there any sign of the cylinders firing - popping, sputtering, backfiring?

Before you installed the Opti, did you loc-tite the rotor screws?

The rust comes from ozone. The vent was added to eliminate the ozone/rust. An MSD cap includes vents and can be installed on an unvented Opti, turning it into a vented unit. Or one of the Corvette sites has instructions for adding vent connections to an unvented unit.

Slayer

When the engine cranks, it sounds normal; it just won't turn over. A few times, it almost turned over, but instead, it sputtered and died.

Yes, I used red Loctite on the rotor screws before I installed the Opti.

I figured other contributing factors to the rust are not driving the car very often and keeping in parked outside. I live ten minutes from the Atlantic Ocean, so it's very damp and humid here most of the year.

rngilliland

Everything you have described points to the Opti being out of time. Since the Opti passed the tests and you have spark at the plugs the Opti seems to be working. Occasional sputtering and seeming like it wants to start but won't is typical of a badly out of time engine.