I just bought this beauty with a spun bearing. Got another engine, put new opti in before installing. Mistake #1 I didn't know I should only use ac opti. I did all diagnostics shown on here. I have no signal going from opti to ecm. Mistake #2 I broke the retaining clip on opti harness at opti plug. Also have no high res signal. Any chance a new harness might be the answer?

 

The harness might be the easiest thing to try first but you could also maybe try to R&R the other opti from the dead engine since it had to be running when the guy spun the bearing. And maybe you can use the original opti housing and encoder and the cap ffom the new opti if you can't get it running.

 

I can't get any spark from the coil. It's not receiving a signal to fire the coil.

 

My ground on the optispark plug is reading to high. I have the pcm ground up above the starter. Any suggestions?

 

Did you replace the opti har ess yet?

 

if you replace the opti, fire the car up before putting the water pump and everything else back on to make sure it's good and that you installed it correctly. You can also try this with another opti to test the harness and whatnot. BTW I found Ballenger Motorsports makes the best small harnesses and pigtails for wiring.


Or of course you can always go to the dark side and go 24x from Torqhead or EFI connection.

As far as grounds, you can always add some more. You should have a ground from the battery to the block at the passenger side motor mount and driver's side cylinder head to the frame with a ground strap.

 

Update found bad plug at coil. Replaced now everything on coil and icm and optispark are correct by SHbox instructions. Noticed the coil wire looks homemade. Found out 96 and 97 have a different coil to optispark wire. I will have 1 Wednesday. Maybe this will get fire from coil.

 

First I've heard of that. You sure you don't mean vented vs. non-vented? Pretty sure OBDII, vented, 96-97 optis and coils are the same and use the same coil wire. I'm thinking part of the reason why you say it was home made is due to the opti plug on the coil wire not being the same as a traditional SBC and has to be either custom built or find a manufacturer who sells a 4th gen LT1 coil wire.

 

I meant 93 to 95 have one style coil to opti wire. 96/97 have a different style wire. OBD1 coil looks like the head of a plug. OBD2 coil looks like a distributor style hook up.
I've been pinning wires for 3 weeks trying to get fire from coil wire.

 

The 95 opti is vented but is like the older style coil where any LT1 spark plug wire will work for it in a pinch. I have a whole bunch of both OBD1 and OBD2 coils if anyone wants them.

 

Thought I would put it out there that I got it running. Had wrong coil wire and bad pigtails to coil and ignition control module. Now that I have it running can anyone tell me why sometimes it idles to high and act like it's searching?

 

Thanks for updating us on how youve got it running but as for why it idles high and wants to search, could be anything. Change on the spark plugs could help or it could be in the tune. They idle really low once warmed up. There is some free software that you can download into your lap top and buy a usb to obd1 cable which will make monitoring and diagnosing the car a whole lot easier.

Did you ever solve why it was searching ?

 

The searching idle was a bad AIC. The car now runs amazing. Hurt my feelings last week when she rolled over 100k. 😒

 

Ah yes ! Good fix. Hey its okay, shes happy to be driven. The IAC has no trouble codes show for it so gotta take a good guess with it. Right now mine gets stuck but no biggie. Have fun !