So I have a 1994 slp formula firehawk (auto) with about 74000 miles and slp shortie headers, k&n filter, holley tb, MSD distributor/wires/blaster coil - all of this was already on the car when I bought it last December. After driving it from Maryland to Florida and back(with a couple FL thunderstorms present) the MSD opti started failing - running terribly after warming up to the point where I couldn't drive it. I replaced the wires/plugs, icm, and coil trying to be "optimistic"........nope still ran like **** after warming up. Then it would barely start. Ordered a $70 eBay opti and removed the MSD unit, took the cap off and saw one rotor screw just laying in the dist. housing, the other half a thread from coming out. Also a fair amount of oil/moisture in and around the optical sensors and disk. So I decided to wait for my ebay opti, I put it on there and she wouldn't start, took it back off & discovered evidence of misalignment (a gash in the center of the key on the splined dist shaft). Realigned and got it back on there perfectly, went all the way home against the timing cover - still won't start. Put the MSD back on there, won't start. Wtf!!!! I'm about to order an accel opti bc I think I killed the MSD by brakleening the exposed optical sensor, and I guess the eBay opti just doesn't work at all?

 

And how the hell do I check OBD1 codes without a scanner?? That jumper trick doesn't work it just shut off the malfunction indicator light...? This car is kicking my ***

 

If the car ran perfect before, it's probably just the opti.. Make sure your wires are ran correctly..

 

using brake cleaner on a optical electrical sensor would likely have killed it. You would want to use electrical contact cleaner sold at places like radio Shack & a Q tip

the one missing and other lose rotor screw on the MSD was likely the reason it was running rough/missing

The cheap off shore made Optis are just a crap shoot to even work at all

 

Yeah that's what I'm telling myself, just emailed MSD tech support to see if they could trade/ rebuild mine? A worthy attempt at not paying $500

 

Yeah in hindsight I should've been more mindful of the sensor(s). Hopefully MSD will come through for me with a budget option

 

MSD will "rebuild" the Opti for $100 IIRC...maybe more now

 

Guess I'll find out. I don't mind $100 at all, they're probably making a killing either way but compared to my other options that seems very reasonable

 

You can't flash codes on 94 or later. Gotta use a scanning solution.

 

Damn I figured it was to good to be true at least for my car, by the way shbox I stumbled upon your opti test via google. Used my voltage meter to check the activity at both the icm and opti connectors, everything kosher there. Thanks for the help

 

So my car is running now - put a new MSD opti on it and couldn't get it started to save my life, so I put it all back together with fresh water pump gaskets and had it towed to a recommended Chevy guru. He called me and said the car had no spark but all the signals going to and coming from the PCM checked good, so he put a new coil on it and it started... (I got the distributer on right but had replaced the original coil with a new one right before doing the opti...) so he said just to be sure he put the coil I had back on and the car started. I picked it up today and it's been running great all day besides a few isolated hesitations, I guess I didn't have the coil connector plugged in all the way or possibly there's a wiring fault in that circuit? Either way my LH power window motor just went out so I'll be working on that if it keeps running well...

 

Hopefully that MSD opti hols up because they seem to be a crapshoot with how long they last. Some last awhile where some die very quickly. $500 for a marginal opti is ridiculous to me. I just ordered a cheap opti from Spectre and used the base and cap/rotor to rebuild my opti. I have a chandler unit on my Vette and the Caprice has the OEM sensor (mitsubishi sensor) in the new spectre aftermarket housing.

 

I also have that $70 ebay opti. I took it apart, vacuum converted it, waterproofed it with the newer MSD cap and rotor that was on the car, runs like a charm. I couldn't justify the $500 MSD or ACDelco opti either, maybe if it was my daily, but for a weekend ride that sees no rain and 1k miles a year, the $70 opti does fine........ knock on wood