So I've been having this issue after a new opti install which should've fixed my car in the first place but now It's running way worse than it ever has since I've had the car. I switched from a factory opti to the msd ventilated without doing the major hardware conversion, I.e. newer timing cover and tapping the cam for the new drive, only because apparently msd's instructions said it was unnecessary. Now It's running like garbage, shakes alot, the engine can actually be seen shaking, major drop in power, stalls every once in a while, idles very bad (low idle like It's gonna stall) and overall just feels like the timing is off or very retarded even tho I've set it to factory settings, fully advanced and back to factory. When I found out my opti was bad I had a local shop that specializes in electronics diagnose a completely different set of symptoms and they said the opti was bad my egr valve was sticking and my stock icm wasn't matching up with my msd coil. Got a new delco egr, all new set of front seals, new timing chain and gears (figured I was already there and the gears were really worn) and the msd opti. Then the problems started. Found out me and my mechanic mixed up 2 plug wires (fixed) and my knock sensor was physically broken (also fixed.) Those all made it run better but still not 100%. Will a mismatched icm and coil really effect it that much or is my icm just no good anymore? Or is there a totally different underligning issue? I've put around $12k into this car including buying it so I really don't want to give it up. Desperate for help so any and all responses are greatly appreciated.

 

so you have the splined shaft opti correct? did you double check to make sure timing gears got installed with the dots lined up

copied from here MSD Opti Write Up

Installation notes:
Make SURE you install the Oring correctly, if you dont the rotor will rub on the optical disk cover and it will fail. MSD is now making a gasket as a replacement to the Oring, you can get one from them.

The Oring installs on the small machined lip on the middle of the aluminum flange, DO NOT mount it inbetween the plastic optical disk cover and the aluminum flange.

My opti has run 100% perfect since about a week after I installed it, initially I installed the oring wrong and it ran not so great. But after I fixed it, it ran AWESOME, way better than the GM unit, it was alot smoother, especially at high RPMs.

Well I just wanted to post this here as a resource for anybody who needed it.

 

If the spline drive is the original 94 design then yes. I can't remember which is which. The gears were actually the 1st thing we checked and they were perfectly matched. The o-ring I'm not so sure about. Is that the large o-ring you're referring to? Cause if so it was pre-seated into the the cap but I will double check...which I'm not really lookin forward to lol

 

andddd yes the icm can do some weird crab.

 

Ok so should I just bite the bullet and get a new icm? Msd of course to fix the mismanagement. And is it the 6al model that I need to get? I've already been looking just in case I have to do that.

 

stock icm will work, i have a msd opti with stock icm and a msd blaster coil and works fine. stock opti does not handle a high output msd coil well. afterthought. check all plugs for cracks. you didnt happen to drop one of the plugs? sometimes thats all it takes to crack em. also make sure the timing advance that the msd has is set to stock position. dang,,, last brain cell is letting me down, cant remember what the stock setting is.

 

Last time I took the plugs out was to replace them and that was a long time ago and I don't remember dropping any of them. And for the msd opti the factory setting is 1 1/2 turns counter-clockwise on the adjustment ****. Which now that I think about it I may have to lock-tight it again cause I've been messing with it alot. And I'll look into getting a new icm. I made the mistake of getting an off-brand opti last time which is why I had to get the msd this time so does brand matter for the icm? If so what should I avoid? Obviously get the factory icm if available.

 

for piece of mind test the opti. i have heard of two guys on here that have gotten bad msd's outa the box. if you can scann for codes do that.

 

Ya me and my mechanic were thinking the same thing that it might be bad. I'll probably get it tested tomorrow. I don't have a code scanner so I'll be goin to aamco. Will their scanners pick it up or should I go to a shop with a high tech scanner?

 

better call first. 94 has a unusual setup. its obd1 with obd1 plug but its not the same as all other obd1's so only certain scanners will work with them. check number 28 here 4th Gen LT1 F-Body Tech Aids