Replacing a 93 Engine and PCM with a 95
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5th Gear
Joined: Feb 2015
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Replacing a 93 Engine and PCM with a 95
Hello! I am going to be removing my 1993 LT1 and replacing the engine and ECM with a complete (built) 1995 engine and PCM (from a corvette also). and I have some questions from the experts on here.
1. The 95 PCM is for an auto and was tuned (PCM for less) for this engine however, I have a 6 speed. Will I need to get it to have it reflashed for the 6 speed and the car?
2. I believe the 95 Opti has a different connector, is it something I can splice in easily, or do I need a full 1995 harness?
3. I think the RPM signal in 93 feeds RPM directly from the coil to the tach and in the 95 from the CPS/OPTI to the PCM and then the tach. Will I need to do anything here to have a functioning tach?
4. I know 93 is speed density and 95 if MAF and I have everything to convert to MAF
Is there anything else I should be prepared for when doing this swap? Any other sensors I need to be aware of that are different or anything else that someone with experience has seen? TIA!
1. The 95 PCM is for an auto and was tuned (PCM for less) for this engine however, I have a 6 speed. Will I need to get it to have it reflashed for the 6 speed and the car?
2. I believe the 95 Opti has a different connector, is it something I can splice in easily, or do I need a full 1995 harness?
3. I think the RPM signal in 93 feeds RPM directly from the coil to the tach and in the 95 from the CPS/OPTI to the PCM and then the tach. Will I need to do anything here to have a functioning tach?
4. I know 93 is speed density and 95 if MAF and I have everything to convert to MAF
Is there anything else I should be prepared for when doing this swap? Any other sensors I need to be aware of that are different or anything else that someone with experience has seen? TIA!
Last edited by cuda99; Dec 7, 2021 at 07:32 PM.
Thread Starter
5th Gear
Joined: Feb 2015
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From what I have been reading it is doable using the PCM and engine harness from the 95. This thread discusses trying to convert a 92-93 batch fire engine to 94-95 sequential:
https://www.corvetteforum.com/forums...uential-2.html
Post #39 seems to have the most concise data, as well as post #47 but I can't seem to find a definitive answer on the CCM interface and if it will cause any issues.
Le Mans Master
Joined: Aug 2015
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From: St. Charles MO
Thank you very much for chiming in here Matthew, this is what I am looking for.
From what I have been reading it is doable using the PCM and engine harness from the 95. This thread discusses trying to convert a 92-93 batch fire engine to 94-95 sequential:
https://www.corvetteforum.com/forums...uential-2.html
Post #39 seems to have the most concise data, as well as post #47 but I can't seem to find a definitive answer on the CCM interface and if it will cause any issues.
From what I have been reading it is doable using the PCM and engine harness from the 95. This thread discusses trying to convert a 92-93 batch fire engine to 94-95 sequential:
https://www.corvetteforum.com/forums...uential-2.html
Post #39 seems to have the most concise data, as well as post #47 but I can't seem to find a definitive answer on the CCM interface and if it will cause any issues.
Thread Starter
5th Gear
Joined: Feb 2015
Posts: 5
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I think you might be right Matthew and thanks again for bringing some logic into this conversation. I was less concerned with the batch-fire vs sequential and/or tuning ease of the later PCM and hoping for a quick plug and play with a tune that was already sorted. I guess that it was well-wishing on my part & nothing is ever that easy.
If the 95 PCM doesn't work, is there anything I will need to do to this 95 engine to run my 93 ECU? I can use my 93 intake and injectors, and I believe the opti connector is the same; anything else I'm missing? I'd rather not go through the trouble at this time to purchase a 24X LS system and computer but it's always on the table.
If the 95 PCM doesn't work, is there anything I will need to do to this 95 engine to run my 93 ECU? I can use my 93 intake and injectors, and I believe the opti connector is the same; anything else I'm missing? I'd rather not go through the trouble at this time to purchase a 24X LS system and computer but it's always on the table.
Le Mans Master
Joined: Aug 2015
Posts: 6,119
Likes: 1,996
From: St. Charles MO
I think you might be right Matthew and thanks again for bringing some logic into this conversation. I was less concerned with the batch-fire vs sequential and/or tuning ease of the later PCM and hoping for a quick plug and play with a tune that was already sorted. I guess that it was well-wishing on my part & nothing is ever that easy.
If the 95 PCM doesn't work, is there anything I will need to do to this 95 engine to run my 93 ECU? I can use my 93 intake and injectors, and I believe the opti connector is the same; anything else I'm missing? I'd rather not go through the trouble at this time to purchase a 24X LS system and computer but it's always on the table.
Thread Starter
5th Gear
Joined: Feb 2015
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Disclaimer: I don't know for absolute certain that it can't be done, and/or maybe if you also swapped out CCMs it would be possible. I've just never heard of it being done, and it would be a ton of work even if it could be done. There are still people who can burn chips for the earlier ECMs like yours. I have no idea what their tables look like, but if you can show someone the calibrations in the 95 .bin file you wanted to use, it might help them get you a good 93 calibration quickly.
I reached out to Tourqhead to see if they have any experience with the PCM to CCM interface on the 93 and this was Paul's response: "At this time we do not have a kit for the early 1992-1993 C4 Corvettes. They are quite different animals with their early style engine wiring and early style PCM. As such our LS PCM kits aren’t compatible and in order to do the conversion on a 1992-1993 C4 you will need to swap engine harnesses to 1994+ style or have custom engine harness made with standard LS PCM connectors. Also to date we have no information if our LCD/CCM module tech (that keeps these elements happy for cluster) will work with the early year CCM modules.
I cannot say for sure if we will never have a LC PCM kit for 92/93 C4’s, but I can say it isn’t planned at the moment or any time soon.
Regards, Paul""
I have a few more messages out there asking basically the same thing but have not received any clarity as of yet. I had seen some instances of F-bodies swapping PCM's from newer to older models but I don't believe the CCM's are as complicated between the F-bodies. But as of yet I have not hear of anyone with experience or expertise to say "yes" it can work if x, y, z are accomplished, or "no" it absolutely won't work.
I'm not 100% certain, but I think everything on the engine (sensors and even the intake and injectors) other than the opti are the same between 93-95. I also think the opti sensors are still the same - it's just the physical design of the driveshaft and the vented cover that are different. So I think it should drop right in and connect properly to everything. If you can have both engines out at the same time in the same space, just do a careful visual check of all the sensors and connectors and make sure they are the same.
Either way, I want to update this thread with what I find out after I have everything sorted. Maybe someone else with some more info will bring something to the table in the meantime.
