I have finally got my 383 ci LT1 installed as of today....It runs decent, but you can tell its rich.....needs to be tuned Im sure. I did a search on here but not sure if I searched under the right topic or not so I thought I'd ask. Is it possible to tune my 96 LT1?? Is there a way to convert it to OBDI and then tune? Can somebody point me in the right direction ......I know its got to be possible somehow....thanks in advance

 

sure get a copy of lt1 edit from carputing or wait just a wee bit longer and see iuf anything else become aviable. those 96-97 lt1 ecms are real bastards to. dual 68hc11 mcus. what junk.

 

Swap out the 96 pcm to a 95. The 95 is editable using the Tunercat system. You'll need to track down some AKM cables, to link to the pcm. I'd also suggest you make up a harness to do the reprogramming on the bench. If you have anything go wrong during programming it'll lock up the pcm, and then you'll have to find someone to reset it. the 95 pcm had OBDI, and OBDII stuff in it, but only the OBDI was enabled. There is some wire swapping since the 95 is slightly different.

You can do the 96 reprogramming, but it's $$$$$$$$$$$$

 

I was actually thinking of doing that.....but wasnt sure if it would work. Thats good news.....would a 93 or 94 work also? I know the 93's were SD correct? Ill look for a 95 or older computer.......will the WinBin program, etc.....aldl cables work like with the OBDI thirdgen's??? Anything else Ill need to buy to get this thing running right??? I got a GREAT deal on a scantool today....so now I can see what its doing at least. Will the scantool show BLM's and INT the same ??? I havent had time to plug it in yet......I will be buggin you ecm experts for a while....hope you dont mind. Ill give you guys a great deal on some tranny work if you ever need it though...lol. Thanks in advance.

 

Actually it's 94-95 that uses the other Flash LT1 pcm
Then in 93 there was the LT1 ECM.
93 uses the 700R4 tranny, the 94-95 is the 4L60E.
Might double check, reverify all that, but I think that's the way it is.

On the newer stuff like that ie 95 and older, I just use Diacom.

 

Yep the 93's had the 700R4 tranny...and in 94 they went to the electronic 700R4(4L60-E). How much would I be looking at to get tuning on this car?? Ive also got the 4L60-E in my car, so can I tweak it also?? I know you can play with shift points...etc, but Ive never really played with the ecm end of them, just replaced the pumps, etc. I found a 94 ecm with the harnesses etc...at a local salvage yard that Im a regular customer at....he agreed to swap even for my 96 ecm. Just wanted to double check that the 94 ecm will have everything in it that I will need to run the 96 motor....or is there any diff in the LT1's after 93(speed density)??? Sorry for all the questions, just want to get this thing running better.....and hopefully get better than 7mpg

 

I know it's been done, just not having done it I don't have the particulars on hand. Maybe a glance some of the LT1 lists would have the details, failing that a run to the local library should turn up the diagrams for the 2 cars.

7 MPG?, something sounds really off.
Make sure the little coils of wire in the MAF sensor are clean. Scrape them with just your finger nail should do it.
Might have also partically killed the O2 with the assembly goo, not all of them are in fact sensor safe.

 

The guy that infact did the machining and sub assembly just recommended that to me today about the lube. Ive also got the 02 sims for the back two sensors.....dont know if that would affect anything. Ive got Hooker LT headers on it with a 3wire heated 02 on each side of the Ypipe(mufflex). I will try cleaning the MAF like you recommended. Will taking the screen off help it?? Im new to MAF cars so bear with me. It just seems like that is such a restriction.....I drove the car to work this morning. It runs pretty good when its cold out. I guess thats because of the cooler, denser air not making it run so rich. I have a modified SLP cold air setup thats actually for the 96 Z that I made fit...so I dont think there's a restriction in the air intake. Im guessing its just the cam thats affecting vacuum. IF you get the car out on the open road like I did today, it SCREAMS Im just not getting any fuel mileage and a ROUGH idle..... Im going to take a trip to the library today and get the other ecm. I decided to just buy it and keep my 96ecm just in case. Ive also found a chiltons manual for the 93-97 Z28/T/A ...might help. Anything else??? Where could I find the directions on making a cable to bench program??

 

3 wire?.
I thought they were the 4 wire.
While on the older ecms you can pretty much swap them around, I dunno about the newer PCMs.
If you have a relatively long straight shot at the MAF you MIGHT get away with dropping the screen the new vettes have, by having a straight shot to it. The LT1s normally use MAF mode, so if the cam if half civilized vac shouldn't be much of a concern. BTW, you can swap to MAP mode with the Tunercat software.

You just need the powers, grounds, and ALDL for bench programming. Least that's all I recall doing on mine.

 

You are right...they are 4wire...just double checked. I didnt get to do most of the install...my dad and brother did it. I just looked at the two in the Ypipe...both are "white-ish" looking.....almost like a head gasket left town..lol. Im going to replace both($$$) and see if that helps. I checked all fluids just to kinda be sure the head gaskets are "good". Everytime I seem to start it...it smooths out more, dont know why though?? When I get the Tunercat, should I switch to MAP mode or just leave it as it is???? Thanks for all the help so far.....

 

White's also a sign of Sillycone.
Start with having things as close to stock as you can, to avoid having too many unknows. Then refine the system from there. On the on LT1 I was involved with, it seemed to run better in MAP only mode. The are two basic cals for it, the F body, and the B body, both are very different. For the Caprice I was working on we kinda sorta averaged the two to start with.

 

welll....got the 02 sensors switched out today....runs ALOT better. Still no signs of anything leaking or bad gaskets....so Im thinking it might have been the assembly lube or something like that. Id still like to tune it just to see how much better mileage I can get and maybe squeeze out a few more HP. Im going to wire up the new ECM this weekend. I was looking at some diagrams in the manuals I found at the public library.....and I couldnt find a schem. for the back two 02 sensors. It only shows a left and right bank....no before and after cat 02's....maybe I over-looked it or something. Im going to really read up before I start trying to tune this one. Could I find somebody to make me a cable for tuning?? and would the diacom and tunercat be all I would need?

 

we were usually using a Snap-On scanner, but I think I linked Diacom to it. I bought a cable form AKM for doing the reflashing, and we just used the Tunercat stuff for editing.

Just remember to snag whatever .bin that is in the PCM to begin with. And you want to start and run the car with no changes again to do the one change atta time deal.

 

It was mentioned that the Tunercat can only edit the OBDI stuff in the computer?? or was it the 95 ECM that has the OBDI and II stuff together?? Ive also heard its not as hard to tune for a larger cam with MAF.....but if they run better in MAP mode....hmmm. I will need to find a cable and get some software next....wish me luck...

 

The 95 only uses the OBDI stuff, it has both in it, thou.
OBDII was required until 96.

Yes, it's easier to tune in MAF since the calibration has less resolution. It's great for running at Stoich. All it takes is flipping a switch in the cal, and you can try both on your own and see for yourself what works best for you.

 

Sounds good Grumpy....thanks for all the info. Youve been extremely helpful. Who can I contact about the cable and software? and Where would be the best/easiest place to find it? Thanks again......After I get the software and cable, etc....Ill post some results if all goes well..lol