I really don't want to get involved in a petty argument.

In post #9 you were “wondering about the grounds attached to the one coil bolt”. You checked that in post #1, got acceptable results, indicate in post #9 you rechecked everything and got the same results, and still were suspicious of the grounds. You apparently checked pin B on the ICM both times, and got 2 volts AC both times, but you said “I might need that Opti after all”. Either you are not reading my replies carefully, or you just don’t understand them.

As far as the rest of your comments I'm not even going to waste my time reading them. You appear to feel you have all the answers, so buy an Opti.

Maybe someone else will put up with your petty bickering.

 

IDK where all this "bickering" is coming from. I started this thread simply noting the values I got from working thru Rob's list (and you're right--his is a more user-friendly version than what's in the FSM), and asked about the current state of getting an OPTI. You then suggested a number of things I should check, and as I noted, I'd love to avoid doing an OPTI; as a result, I checked/tried everything you noted. I have no interest in being right, or the authority--only in solving the puzzle.

Those 3 ground wires @ the coil aren't even mentioned until #7, when I noted they were torqued down so tight, I hadda break 'em to get it free. But when you do something that results in an unexpected result--in this case, swapping the coil & ICM and triggering a code 41--you need to go back and question everything you did. Included is putting on new terminals for those 3 grounds. Heck, I said I was "grasping"--but am willing to go back and question what I did. Maybe I missed something, or did something wrong--dunno. If so, I'm willing to address it--see the last sentence above.

You suggested I review the FSM, which I did. And again, I got the approp. values when working thru DTC 41. The result--according to the FSM--is either a bad connection or a bad ICM. Since the connection checks out, that leaves the ICM. Did I get a bad one? Since no place down here can test it, dunno, but am willing to accept the possibility. But after trying 2 ICMs (the old and new) and getting the same result, I'm skeptical.

At the top of A-3 in the FSM, it says if you get any of these DTCs--41 among them--you need to work thru that first, which I did. I worked thru the flowchart and the result is either a faulty connector or "faulty distributor." As I've said repeatedly, I'd love for it to be something else, and am willing to try whatever, but trying the same things over and over and getting the same results...well, you know what they say 'bout that. That 41 is the result of the changes I did, but everything checks out. Heck, I bet if I put the old coil back in--bad tho it is--the 41 would vanish.

Tell ya what I'll do: I'll call Chris @ Petris, tell him everything I've done/checked and see what he says. From what I read on his site, it seems he's as much focused on making sure a customer actually needs an OPTi as he is on selling one. That's a good sign. And I agree they are prob. the best option, judging from what I've found on the web.

All this stuff about "bickering" and argument is really perplexing to me. Review my posts carefully. I'm a very easygoing guy. I'd rather have my Z outta the garage--I had planned to work on my other vehicles & this puts the brakes on that--but it is what it is. Again,. see the last sentence in the 1st graph: I'm only interested in solving the puzzle.

 

Had some time this AM, and just to see what happens, picked up a stock-ish coil (>8k ohms) & swapped it w/ the MSD coil to see if DTC 41 still comes up. Started a scan, cranked it and...nada. DTC 41 has vanished. Only thing I can deduce from this is that the PCM isn't adjusting to the signif. change in resistance. Regardless, after running all the diagnostics multiple times & coming up w/ the approp. values/results, chart A-3 of the FSM points squarely @ the OPTI.

Also checked w/ Chris @ Petris, and he has splined units available, and is currently making more. After looking @ the options on the web, prices for these run from ~$60 - >$800, and in most cases, you can't be sure what you're getting. Petris is in the middle, cost-wise, and after reviewing a plethora of comments from 2019+ on various sites, everyone seems to agree that these are prob the best available--not a single negative comment. There was a guy on eBay who used to reman 'em and got similar high ratings, but I checked & he must not be around anymore. Petris it is.

The swap is pretty straightforward, but since I'm really old, not very big, not exactly the picture of health (thank gawd for air tools) & in no great rush, it'll prob take me ~4 hrs or so to do the deed. Will let y'all know how it turns out.

 

Have you swapped out the opti?

 

Not yet. Had some problems navigating his payment portal, so gotta do it manually. Hope to have it sometime next week, and will set aside a day to do the deed. Not a job to rush thru.

Are you in the same boat?

 

Im on Brand new opti #8 and still cannot get a good one. Ive been using summit racing, autozone, oreilly.

 

I noticed your other threads in here & took a look, and based on what you say--and what all has been done to the car--at the risk of sounding a bit like Injun, I don't see any diagnostic proof you need an Opti. If you've tried 8 "brand new" already, that should be a tip that something else (or in your case, multiple something elses) is the cause. It's possible you could get 1 DOA, but 8? Highly unlikely. And you mention @ 1 point that you tried a known good Opti & it didn't work--but you put it in your friend's car and it worked just fine. That should tell you something. Where are the diagnostics that led you to the Opti?

The big knock on Optis has to do more w/ longevity. Units w/ poor construction, substandard components (optics, etc.) & a general lack of thorough testing are legendary on the boards for short lifespan. Many, many guys point this out--they went el cheap-o & soon needed to do it again. That's not the pattern you outline.

Given all the changes that have been made, I can't suggest a fix, but taken as a whole, there doesn't appear to be a methodical approach to troubleshooting. Instead, it looks like a scattershoot approach, where parts & money have been thrown at it hoping for a fix. Given all the changes, tracing down the cause(s) will be difficult. I know your frustration level is high, but it sounds like you have a good shop looking into it; let them do their thing and see what they say. You've tried a number of diff tunes, but a good tune should reflect the actual modifications (like, say, a cam) that have been made. Your guy says he can do that--give him a shot at it.

In the future, I'd suggest methodical diagnostics, and there are a plethora of tools available. First, get a (free) copy of Scan9495 (it's linked in a sticky in here); GaryDoug wrote it, and it's the best scanning tool around for these cars since it gives you a running datalog that will show you exactly what is happening at crank, closed loop, WOT, etc. You can scroll down and see it, and compare it side-by-side w/ other scans to see what changed. Injuneer also has a guidebook posted somewhere in here (I think it's in a sticky) that will help translate what's in the scan; it's a tough read, but very worthwhile. You should also get a copy of the FSM (factory service manual); Injun supplies the link in this thread. Check out the flow charts for diagnostics. There's also Rob's site (shbox.com), a more user friendly version of the FSM, which has diag tips, lots of photos & plenty of good info. You might also find a copy of the Haynes manual.

Everytime you make a change, do a scan and document the result. Then, if it doesn't work out, you don't need to keep tossing parts @ it and boosting the frustration level. To the point here, a good Opti will run ~$500, and if you don't have clear diags to substantiate it, I wouldn't be in any hurry to spend the $$. Better to let your speed shop go all thru it first and see what they say.

 

So finally got my Petris unit and did the deed. It went pretty well--and the Opti was indeed the issue. The normal gotchas you would expect for a ~30yr old car--removing things that had never been removed, etc.--but I got no complaints.

Even the coolant swap went better than expected. I used a variant of what Rob calls the "alternative" and did a garage back flush; since I have a larger Magnaflow exhaust, it's almost impossible to get to the knock sensor & drain plug, and it would be even tougher since they've never been removed (at least not in the 25+yrs I've had it). I had a shop do a power flush about~5k miles ago, so I figured doing it myself would be fine. I noticed in Rob's write-up that he mentioned guys had indicated they poured the mix straight into the WP, and had reported this lessened considerably the amount of air bubbles. That's what I found, too. Had to check it a couple times to top it off, but there were few bubbles and they disappeared quickly.

The only downside was after I buttoned everything back up. It started right up and idled well, so instead of doing a scan first, I took it down the street for a drive. Mistake. When I punched it, I heard a THUNK down around the tranny, so immediately took it home and ran a scan. It pulled 3 DTCs; I was able to resolve 2 quickly, but the third is turning out to be a real PITA. But I'll start a new thread for that.

All in all, anyone who is considering doing this themselves should give it a whack. True, it's time consuming (I did it over a few days, and prob spent ~6hrs total) and messy, but you'll really get to know your Z--and think of all the $$ you'll be saving (didn't check on cost, but I bet it would be ~$1000 in labor alone). You really don't need any special tools other than maybe a three-finger puller (for the balancer--Autozone will let you use one for free), just a full compliment of all the various sockets & ratchets. And get yourself a good Opti; you can go cheap, but you might be doing it again in short order. Pay the xtra $$ and be done w/ it.

 

Good for you. Hang in there. Sounds like you have the right stuff for these cars ;-)

 

I myself live in Pennsylvania and same happened to me and I bought a summit brand and that was back in 2016. And still runs like a champ !