Messed around with it yesterday. It idled like a champ for 40 minutes or so, no stumbles, no hesitation, and it sounded healthier too (probably a placebo but the motor just sounded better). Seems like the solder sleeves held up just fine.

 

 

Well... We're back again.

After a fair bit of work, the car is back together and trying to get it ready for a track day in like 3 weeks. Decided I was gonna take it to work as a shakedown... No bueno. Similar symptoms again, engine dies randomly, sometimes it comes back on its own,.sometimes you have to crank it over again. When it fails, it loses tach signal.

What's a little more odd this time is it idles just fine. I'm thinking it's probably the coil connectors again, and those solder sleeves were not up to the task with vibration and the like. I guess I'm gonna have to use a crimp sleeve instead.

 

I find it somewhat amazing that someone has not taken over where the Optidoctor left off. Maybe offer to pay him to find out where he got parts, how he did the bearing and what he used to seal it up. There would seem to be enough demand to professionally rebuild original optis. Dan

 

I think that's essentially what Petris does. They buy an Opti, and then basically tear it down, check it, and ensure it's built right, adding the vent hookup at the same time.

I don't think the market for Optis is as big as it would take to really get an ROI on it, maybe it'd be fine for someone who wanted a hobby retirement job, but doing an opti restoration and having to compete with all the options already available is tough.

 

I had an email exchange with Optidoctor Brad earlier this year when my 2-1/2 year old Petris died. Read 'between the lines' and the take away is that these guys were/are using aftermarket optis, changing the cap, adding a vent kit and re-branding them. These guys didn't have a magic source for the "electronics". They were using what comes in a current Cardone. Or reusing the original electronics which DO fail, as the Delco that was on my car when purchased certainly did.

Petris sold or retired or something. Brad wound down his operation. Like the 4+3, DMF clutch assembly, it seems that the opti is also an obsolete component with few if any options for a reliable repair that lasts. I just installed my 4th one in 3-1/2 years. This is my first and last LT1.

Here's a copy/paste of the email.

Brad Errington

to me

Jan 1, 2026, 12:39 PM



Hello,

I’m sorry to hear you’re having Optispark troubles. It is frustrating. I’m guessing your old OEM Optispark failed electronically. When they look pretty good inside, but don’t function… it’s a good bet the Mitsubishi sensor has checked out. The 92, 93 and 94 Optispark sensors are not as robust as the 95 and later units, so it’s getting tricky for me to rebuild those. I don’t currently have any used ones to rebuild.

I can offer 2 options to consider:

1. I can build you an aftermarket optispark that will be free of assembly errors, sealed and tested on an oscilloscope. This is similar to what Petris does. I start with an aftermarket unit and I reassemble it with sealant, loctite and some USA care. Cost is $360

2. I have a NOS in the box AC Delco OEM Optispark that would be really robust for $850

I’ll send some pics of the NOS unit. It’s impressive.

Let me know if you think I can help.

Brad

 

Meanwhile my 15 year old 150K one from some random autozone back then is still working away
Knock on wood. I still attribute this to having the remote coil setup on it. If I ever rebuild this motor I'm going
to replace the ignition setup with something else, my luck is bound to run out eventually.

 

^^ Totally irrelevant. ^^

This thread is discussing the 1992-up Optispark distributor.

 

96 LT1 lol... I put a parts store opti on it when I put the motor in the Jag 15 years/150K ago.
Did the remote coil conversion about 5 years ago. Maybe generic parts store replacements
were better back then.

 

@wolf_walker what is the "coil near plug conversion?'

 

https://www.bailey-eng.com/product/l...der-converter/

 

Did some troubleshooting tonight. Pulled the coil plugs off and checked the wiring. It was not exactly what I would have called tight, and absolutely was going to cause a problem at some point, if it isn't the issue now. I was able to pull all of the connections apart without breaking any of the wires, the solder sleeves quite frankly had not soldered, and the wires were basically just held together by a heat shrink and a melted lead (or whatever it is) sleeve. Maybe acceptable for low stress joints, but definitely not for a high heat, high vibration environment like an engine bay.

I ordered a new pair of crimpers that do a nice square crimp on a circular tube, they're technically for ferrule connectors, but the pattern seems to work very well for non insulated copper sleeves. So some copper crimp sleeves and a little bit of heat shrink later and we have a much more sturdy connection that will hopefully resolve this repeat issue for good.

As an aside I used these same solder sleeves on my ECT wiring, and my wiring to my heated o2 sensors, so I guess I have to keep an eye on that too. I think those are probably less harsh environments than being plugged directly into something at the front of the engine, but I'll have to monitor it. The O2s will be tough to check for, but the ECT wiring should be easy, as long as the coolant temps don't disappear it's fine lol.

 

Mini update.

Drove it just a little, it didn't stall out or act like it was going to, but it was running oddly, so I brought it home. I think I was correct to be concerned about my use of the solder sleeves on the o2 lines, it felt like it just wasn't running with the right a/f ratio, and frankly it felt like it was running a bit better after I had turned around (as if the O2s had fully heated up?).

I'm gonna try to change the solder sleeves on the o2 lines out for crimps tonight and drive it around some tomorrow. Hopefully that better connection will result in better running and close this whole issue out.

Also I saw no drop outs of the ECT, so I guess that wiring worked out fine? Weird but whatever.

 

Further update.

With the O2 wiring fixed it runs a bit smoother (though the car does complain about running lean if it sits at idle, but not under load - weird). Drove it around a little bit, it was mostly stable, but then the tach signal died, got it home and started playing with wires. Messing with the wires at the ICM would cause it repeatedly. Unplugged it, tried another ICM, no dice. Plugged it back in and it stopped doing it largely. Drove it around for like 30-45 minutes doing some errands, drove fine until I was on my way home, when it started doing it again. Ok,.so the ICM needs a refresh, that's fine.

So current plan is to get a new ICM, a new and much larger heatsink, and mont it on the radiator shroud. The intake is pulling from there so it should have decent airflow to keep that all cool. I had previously kinda poo poo'd this idea before, but now I have to do something so it doesn't seem like a bad idea to try to do something better.

 

My bet is that it is the connections in the plug on the ICM. Not the ICM itself.

This has been going on for months. If it was an intermittent ICM, it would have failed entirely by now. Months long intermittent are typical of a poor connection. Look inside the ICM side of the connector for distorted or loose terminals. Use a tiny pick to squeeze the terminals for a tighter connection. Also push/pull gently on the wire while observing the terminal in the connector shell. The metal must move with the wire. I had an ECM ground wire terminal that had fractured causing intermittent rough idle and stalling that took over a year to pin down.

There was another guy on here that had distorted terminals causing intermittent drivability issues. I don't recall the exact component involved, but it had similar terminals to the LT1 ICM connector. He reformed the terminals with a pick and solved his problem. Look in the holes at the condition of the terminals. I'll bet one or more are 'loose'.

 

I agree, I bought new wiring and connectors to replace it, I suspect the years of heat and vibration cycles have worn down the female terminals. The new ICM is more of a "just in case" thing, a spare ICM does you no good if it doesn't work.

That said, this car sits a lot. It sat for months while I was doing exhaust, it sat for weeks with me not troubleshooting it, it just sits a lot lol. So I wouldn't put much weight into the timeframe of it all, lol. It has probably had 2 hours of drive time since I made this thread lol.

 

Neither; Chris Petris is still owner of the Optispark building business, its a long time family business. He's been active for decades in the corvette performance businesses. I'm with you though, if this petris fails before I die i'm goin with that Torqhead set-up next time.