Looking for some advice on my issues, I am starting to run out of ideas. Took the car out of winter storage this year, drove it around the block to test the LS1 front brake setup and the car died shifting into 2nd gear. To make a long story short, the issue was the rotor on my MSD opti had come undone and was flopping around.

I sent it to MSD to be checked/rebuilt and received it back. They pretty much replaced everything on it except for the wiring harness. Put it back in the car, and everything seemed to be OK. I did notice a slight miss at 2400rpm, but figured maybe the car needed new plugs or something. It was driving OK for two or three trips, but I went to start it one night and the idle was all over the place. It ended up stalling at the bottom of my driveway. Managed to get it started and back into my garage.

I've already put new in plugs, wires, coil, IAC valve, new TB gasket, fuel filter and tried a different ICM. I also gave the car a thorough look over and replaced some vacuum lines just due to age. Vacuum lines and wiring all looks good. Fuel pressure tests good. I am getting the proper voltage as well as cranking voltage to the ICM and opti harness. The resistance on the IAT and coolant temp sensors check out OK. I also replaced the coil and opti harness connectors as the pins were pushed up a bit and probably not making good contact. There is no unusual mechanical noise and I can't hear any exhaust leaks.

I still have a very rough and erratic idle. It will start, idle at 1000rpm and then shoot up to 1500, 2000, 700 etc... The last time I drove it after replacing everything above it was still misfiring all along the rpm range.

I hate to say it, but I am leaning towards the MSD opti being bad. I am mainly looking for suggestions on anything else I can check before I tear it down again and swap the opti. I did read a thread somewhere saying that MSD got a bad batch of sensors, but I don't know how true that is. I'll probably be giving them a call tomorrow...

 

I'd start with triple checking the spark plugs gap.

 

I checked that too. The plugs (NGK TR55) were gapped at .040, the same gap as the ones that came out (also TR55). The old plugs looked good, no abnormalities.

 

I have read the thread on another forum. The moderator, injuneer, was working with MSD on what is now a rash of OPTI issues. MSD claimed the source of their optical sensors seemed to be the issue......but they stopped communicating further as to wtf was going on.

Sounds like you are in the MSD bad Opti group

Given what you have swapped already...I would put in a non MSD Opti. Ideally a AC Delco

 

Do you have any suggestions where to find a non re-manufactured Delco? I looked around and can only find reman units which don't seem to come with the Mitsubishi optical sensor.

 

No I don't. Somewhere there could be NOS one sitting on a shelf somewhere

Maybe a GM dealership in bum F Idaho for example. Usually dealership parts counter can do a network "search" to locate one and either get it shipped or just give you the 411 and you contact them directly. I doubt that as Mike at Hamilton Chevy in Michigan who offers parts says he just has the reman ones. IDK if those have the original Mitsubishi sensors in them or not.

or junk yard one you take a chance on finding a original one with a good sensor and rear bearing

Given there are so many B, F & Y bodys made for a given 93-97 years there must be many in junkyard motors

 

about everything out there is now a reman. it's all a crapshoot anymore.

 

Thanks everyone for the suggestions. I am going to give MSD a call tomorrow and see what they say.

 

"Buy our product! It's the best thing evaaarr!" is what they'll say.

 

Haha, hopefully since I already have their opti, they will say "send it in and we'll take a look at it no charge!"...

 

You just got it back, if I understand your initial post, from MSD so they will take it back under warranty. IDK if they "fix" yours or just send a new one.

When I returned my new, had high RPM stumble, MSD Opti it was after a year (chased and replaced every other ignition part to resolve the problem over the coarse of a year and I didn't even install it until 6 mo. after I got it) so no warranty and I had to pay $100 for a "rebuild"...they just sent a new opti. IDK if thy even repair returns and just send new replacements or not.

Call them, get a RMA# and send it back. IMHO I would get a ACDelco, even reman, and sell the MSD opti. My MSD Opti never worked right......YMMV

 

Going to put a close to this issue. I put in a Cardone Select opti and the car runs perfectly. It also addressed three issues that I've had with the car since I bought it (I've had the MSD opti on the car since I bought it 9 years ago, the original crapped out driving it back from the dealer in NY).

- I had times where the knock sensor would pull timing randomly. This is now gone.
- While datalogging, I would always notice a split second spike where the rpms would jump to a number that could not be true. For example, at idle with no throttle input, the rpm entry in the log would show 5000rpm for a split second and then return to normal.
- I would also get random connection errors that I also no longer get when datalogging.

So I've basically had a bad opti for 9 years and never thought anything of it. It feels like a new car, the low rpm has much less surge and the car feels stronger, but it could just be because I haven't driven it in a while.

I used to be very pro MSD for the opti, but now I absolutely can not recommend it. Go with anything else... it looks nice but that's about it.

 

The MSD cap & rotor is good whenever it comes time to do a C&R

Don't touch that Cardone Opti...it works...they don't have a good rep but if it works keep going

 

Well so much for the Cardone opti. Tried starting the car the other day and it would not start. Managed to get it started today after 3 or 4 tries and it now has code 36 - high res failure and both fans are on. Tested the wiring again, getting proper voltages as well as the opti harness which also tested OK.

Anyone get one of the Summit optis recently? I really wish I could find a new, non-reman Delco or Delphi. If anyone has any leads to one, I'll send you a finder's fee!

 

I am having similar issues with my car only when warmed up. I tried the oreillys brand opti and it was garbage. I then tried the summit brand and it seems like a better built unit but I'm still having warm idle issues. Not sure if the opti is actually my problem though now after trying 3 different optis on the car. I'm also wondering if there are any new delco optis still out there as i'm hesitant to try a rebuild. I'll let you know if i find anywhere that has them.

 

It could be a bad ICM, they usually work OK until the car gets up to temperature.

I'm ordering a Summit opti tonight. I was hoping a new Delco would pop up somewhere, but they just aren't out there. If this one craps the bed, I am seriously considering going 24x via TorqHead...

 

The Summit opti is a re-labelled Accel unit. stay far away.

 

Put the Summit opti in and the car runs well again. I compared it to the Cardone opti and they look almost identical. The Summit opti was stamped July 2013 on the housing, I guess they don't sell many of these or they have a ton. The only difference I noticed was the casting on the back of the Summit housing was a little nicer. Hopefully this is the last one I need for a while, this is the 3rd opti swap I've done in 2 months. Thankfully water pump gaskets are cheap lol!

Also put in an LT4 starter and it got rid of the screeching noise the original starter was making. I thought it was making noise because of the aluminum flywheel, but I guess it was just tired. It sounds different too, much nicer.