kimmer

Ok, changed the opti and as you can see it needed it. Now I still have a no start condition with no spark from a known good coil and icm. I stumped.

leesvet

Thats pretty well trashed...amazing at what will actually work when we see so many things that are so fragile..like the Opti.

I'd say connections. Go thru all the wire plugs and contacts. Thats where the only work was performed and the car ran prior to that, so its either HUGE conincidence that something else failed OR its in that area...a "new" part might not be good..

PLRX

kimmer

Actually it did not run, it broke down on the road. As you see the opti needed to be changed, I had coil spark before the transplant but it was weak. Don't have any now, it's a real pisser thought for sure this would be the fix.

93Rubie

I don't always downshift, but when I do, Opti-Sparks explode.

PLRX

I'm willing to bet a 12-pak that the great C4 ultra crackable plastic is the reason of that type of failure. I wonder if the C5 and C6 are having that issue with heir plastic parts.

kimmer

Pretty well destroyed, now any ideas why I have no spark from the coil, ECU?
There are no stored codes. Checked coil and icm both ok.

Tom400CFI

Do you have a scan tool?

Does your tach move at all when you're cranking?

BrianCunningham

kimmer

No it doesn't.

FrankieD

check both ends of the connector that feeds the opti. First one is located along the passenger side of the intake manifold and the other feeds into the top of the opti. If connections seem good you can then try taking voltage measurements on the connector thats on the passenger side of the intake manifold. If this connector is bad it will not feed the Opti.

kimmer

Thank's, will check it.

1985 Corvette

Looked good on paper in dealer brochures

Doug Nash 4+3

VATS

Optispark

93Rubie

They will, give them 20-30 years. We'll see how they hold up. Frankly, I find my C4 to be very robust for the most part. The drive train is dang near bullet proof. Unlike C5/C6 half shafts.

ScaryFast

Here's a list I've used forever, sent to me by another forum member years ago. Hasn't failed me yet...

I had a coil that was bad out of the box. I'd start there. It was an MSD, by the way...

kimmer

Ok gone through pretty much all the tests and I'm not getting 12v from the coil connector accept on the tach side. No 10v from A&D from the driver. Findings according to fsm are faulty ignition feed circuit to coil or grounded external coil circuit. Where do I start looking? Bty the coil and ecm fuses are ok.

kimmer

I am getting the correct readings from the opti harness though.

FrankieD

Your Coil primary is open. Sounds like you got a bad Coil. Have you measured the resistance (ohm) reading of your Coil's Primary. This reading should be about zero.The Ignition Control Module Pins A & D are feed from 12v ignition through the Coil's Primary windings. If the Coils Primary is open it will not feed the 12v to pins A & D of the Ignition Control Module. And yes a new Coil can be defective from new..double check the resistances of the Coil windings.

With the Coil Connector unplugged from the coil you should have 12v reading on the Pink/Black wire with ignition on. This is what feeds the Coil Primary. If there is no 12v on the Pink/Black wire then that is your problem.

kimmer

Would this be on the black or the grey connector?

FrankieD

this is the circuit path:
When ignition is turned on 12v goes through the "10A Coil Fuse" and feeds the Pink/Black wire on the Grey Connector. This same Pink/Black wire is directly connected to the Pink/Black wire on the Black Connector which feeds Pin A on the Ignition Control Module.

You need to verify that you got 12v on the Pink/Black wire of the Grey Connector when ignition is on (measure this while the connector is unplugged from the coil)

If you do not have 12v then check the "Coil Fuse" which you previously mentioned that it is ok. Double check by measuring if the 12v is directly on either side of the fuse when ignition is on.
If you do have 12v on either side of the fuse then that means the Pink/Black wire on the Grey Connector is broken somewhere in between from the fuse block towards the Grey Coil Connector