LT1 tuning

[Six_Shooter]

I've been looking at what is required to tune the '94 to '95 LT1 using Tuner Pro.

Software

I can see that there are files available for performing the actual logging and tuning.

I have found that there is a program provided by Tuner Cat called WinFLASH to be able to retrieve and load files from and to the PCM, 30 day trial or $20 registration. Are there any other programs, or preferably a plug in available for Tuner Pro RT to provide the same functionality?

Cables

This is where the information seems to be a bit thin. I found information that AKMCables sold a cable (actually a few variations) to be able to log and tune these PCMs, AKMCables is no longer selling them, but have posted that Tuner Cat is now selling them.

What other cables work? Does the Moates.net ALDU1 work? It would be great if the ALDU1 works, because then I just need to buy a CABL2 to add to my already overflowing tuning bag, instead of a complete additional cable set-up.

Other information

All information points towards no ability to tune real time with the LT1 PCM. Has anybody modified the PCM itself to be able to use an emulator in place of the flash chip, like how the RoadRunner is designed to work?

It would be great to all set-up information on one thread (I could not find such a thread), starting from materials needed to any special set-up information that could be used by anybody looking for information to tune any LT1 PCM.

[RobertISaar]

any ALDL cable will work to flash the PCM.

madtuner.com created a flashing program for both the 93-95 3100 PCM and the 94-95 LT1 PCM. it works with a lot more stability on a newer OS than the tunercat program does.

you CAN remove the EEPROM from the board to run an emulator in place of it, but it's PLCC, so it's not as easy to do as DIP stuff. also, you would need two emulators since there are dual processors and dual PROMs, if you wanted to emulate both sides at the same time.

[EagleMark]

TunerCat WinFlash is the only software I know of to do the flash. $20. Nothing TP related.

Your ALDU1 will work fine, I've also used the AUtoProm or any ALDL cable. Not many 94-95 vehicles had the OBDII ALDL port as Moates site says so may not even need the CABL2 but it will work with 96-97 LT1 to flash Also with ALDU1.

No emulation available for LT1...

[EagleMark]

I've never had an issue with WinFlash.

Couple things to note about flashing a PCM in vehicle. Make sure vehicle charging system and battery are good. All accessories off! Laptop fully charged and NO CHARGER!

[Six_Shooter]

Robert; I'll look into the program you suggest.

I'll likely be doing this mostly on my bench, right now I have one guy that will want me to take a PCM that has a modified bin file on it and flash it with a stock bin file, so for my bench set-up I could likely add an OBD1 ALDL connector, but would need the CABL2 for some in vehicle flashes then.

So, it looks like I can tell him for I can do it. :)

[96lt4c4]

Robert; I'll look into the program you suggest.

I'll likely be doing this mostly on my bench, right now I have one guy that will want me to take a PCM that has a modified bin file on it and flash it with a stock bin file, so for my bench set-up I could likely add an OBD1 ALDL connector, but would need the CABL2 for some in vehicle flashes then.

So, it looks like I can tell him for I can do it. :)

Do you have an Moates Autoprom? This is the best tool I have. Burn chips, emulate, datalog, and flash 94-95 LT1 PCM's, I have both ODB1 and ODB2 cables for it that allows flashing the 95 to 97 cars. I usually put the ODB1 PCM's in the 96 and 97 cars for easier tuning.

My setup is this

TunerPro RT
Moates Autoprom
Tunercat winflash - just load .bin in from Tunerpro and flash

works great, the only problem I have ever had was flashing a Corvette with the PCM still in the car. The VATS and CCM in the corvette talks to the PCM and will hose the PCM up. So from now on I pull the PCM and bench flash it on the Vettes. Impallas and Camaros, I have not had this problem.

[EagleMark]

the only problem I have ever had was flashing a Corvette with the PCM still in the car. The VATS and CCM in the corvette talks to the PCM and will hose the PCM up. So from now on I pull the PCM and bench flash it on the Vettes. Impallas and Camaros, I have not had this problem.This is also an issue on OBDII cars when doing a full flash, can really go bad if not done on bench without being tied to other modules. Partial upload of tune is not an issue, full upload or VIN change is.

I didn't know OBDI Corvettes had an issue...

For bench flashing and Vin changes I had an issue with just power. It needs power and Key On Ignition power, after a flash turn off key on power. Just like in a car. Some save changes when Ignition power is turned off yet PCM still has power. I just do them all this way now. Fully charged car battery, fully charged laptop battery, no noisy AC power supplies or chargers.

[96lt4c4]

This is also an issue on OBDII cars when doing a full flash, can really go bad if not done on bench without being tied to other modules. Partial upload of tune is not an issue, full upload or VIN change is.

I didn't know OBDI Corvettes had an issue...

For bench flashing and Vin changes I had an issue with just power. It needs power and Key On Ignition power, after a flash turn off key on power. Just like in a car. Some save changes when Ignition power is turned off yet PCM still has power. I just do them all this way now. Fully charged car battery, fully charged laptop battery, no noisy AC power supplies or chargers.

This would only be in the 94, 95, and 96 Corvettes. The car I had a problem with was my 96 with a 95 PCM to convert to ODB1. The flash went south. Pulled the PCM, I had to change out the flash chips with 2 new preloaded ones. I installed sockets on the board. Then the PCM started talking again. I built a bench setup and reflashed it, then put it back in the car.

I also have a really nice Agilent DC power supply that I run them off of. I usually flash at about 13 VDC.

[EagleMark]

Since all body style LT1 had VATS I don't think it was that. Now the CCM in Corvette is even an issue with data logging. But again never heard this issue in OBDI reflash. So it seems to be the OBDII Corvette to OBDI that had an issue? Did you ever flash the OBDII in that Corvette? Just curisoty to avoid future brick PCMs...

[96lt4c4]

Since all body style LT1 had VATS I don't think it was that. Now the CCM in Corvette is even an issue with data logging. But again never heard this issue in OBDI reflash. So it seems to be the OBDII Corvette to OBDI that had an issue? Did you ever flash the OBDII in that Corvette? Just curisoty to avoid future brick PCMs...

No, never flashed the stock PCM, that was the reason I went ODB1. I already had an Autoprom and Tunerpro so all I had to do was get a used PCM, Winflash, and a cable. At the time I thnk the only software that suported that car was LT1 edit ODB2 maybe others...

Aparently it did not always happen, some guys on the Corvette forum reported it happening and some did not have the problem. It may have just been my luck. After fixing my brick PCM I never had any problems falshing it outside the car. It seems like I remember reading that the CCM comunicating with the PCM cause the problem and that it could also be avoided by pulling a fuse.

[sherlock9c1]

Ressurrecting an older thread, and please forgive my rambling as I try to spit out everything in my head:

So the $EE '94-95 LT1 computers have two ROMs in them, can we assume that the single bin file that TunerCat uploads goes to both chips since the chips are 64kB each and the tune is 128kB? Has anyone gotten to the point where it's known which data is on which chip, and which chip uploads first?

I just cracked open my toasted PCM which had already previously been repaired once and as far as I can tell, they only repaired the Time chip, not the Event chip. I wonder how they knew which one was hosed? The most recent failure was at 80% complete, does that lend any hints as to which chip has the bad image? Then again, if the previous repair was on the Time chip, does that imply that the PCM's OS boots from the time chip and that's the critical component for booting in order to be able to successfully reflash?

I see ROM emulators available for DIP chip layouts but not PLCC - it seems doable to wire in an emulator for one or both of the chips but then the next question goes back to my mumblings above - how to figure out which data is on each chip such that ROM emulation and real-time tuning could be successful.

Okay fellas, the dartboard's up, throw some darts at it! :wtg:

[sherlock9c1]

...the only problem I have ever had was flashing a Corvette with the PCM still in the car. The VATS and CCM in the corvette talks to the PCM and will hose the PCM up. So from now on I pull the PCM and bench flash it on the Vettes. Impallas and Camaros, I have not had this problem.
For posterity, the 1994 B-car factory service manual (page 8A-50-0) indicates that the PCM, ABS computer, airbag computer, and the Buick automatic climate control unit all share the serial data line. Although my Roadmaster has had 15 successful tunes (and no unsuccessful ones), it does support EagleMark's mention that a benchtop harness gives a dedicated line to the LT1 PCM during programming.

[RobertISaar]

Has anyone gotten to the point where it's known which data is on which chip, and which chip uploads first?

we had this figured out in one of the threads... not sure which one though, and i can't come up with the right search terms to find it either.

[EagleMark]

Strange how I flashed my 94 Roadmaster 100 times without issue.

Was a pain to get the ADX to work and I picked the hardest one to learn on because of all the modules you listed.

What car, or modules are in your car that may have caused this? Are they in the RoadMaster? I think the CCM for dashboard is only one it does not have and only in Corvette...

[EagleMark]

we had this figured out in one of the threads... not sure which one though, and i can't come up with the right search terms to find it either.I really need to install the better search add on for this site...

[RobertISaar]

google to the rescue:

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1160-64K-bootable-image-for-95-LT1-PCM

side with blue and gray plugs is T-side.

[EagleMark]

These benchtop diagrams may also shed some light.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?335-16188051-and-16181333-PCM-Information-EE-EEB&p=19721&viewfull=1#post19721

[sherlock9c1]

Strange how I flashed my 94 Roadmaster 100 times without issue.

Was a pain to get the ADX to work and I picked the hardest one to learn on because of all the modules you listed.

What car, or modules are in your car that may have caused this? Are they in the RoadMaster? I think the CCM for dashboard is only one it does not have and only in Corvette...
All of those modules listed are in the Roadmaster. My Caprice is a 9C1 police package but the VATS module does not appear to share that line. I'm wondering if it really comes down to my ALDL port being loosey goosey because my Roadmaster never had one problem datalogging, flashing, nothing, whereas the Caprice had quirky logs now and then and has toasted two PCMs.

[EagleMark]

I'm wondering if it really comes down to my ALDL port being loosey goosey because my Roadmaster never had one problem datalogging, flashing, nothing, whereas the Caprice had quirky logs now and then and has toasted two PCMs.and there's your sign!

Plus the Caprice has never been an issue to flash but it's a 9C1 so who knows how many wires were tapped into and out of when it was in service.

I don't think any VATS modules are tied into serial data line? Also the VATS in a 9C1 does not have starter relay off VATS, just fuel cut off to PCM.

[sherlock9c1]

and there's your sign!
Hah, where's the LOSER smiley? :thumbsup::innocent2:
With all the links you guys posted, it looks like I can take those two BNDH chunks, get the BNHD bin, fire up my trusty hex editor and find what's on what chip. Now just have to find the time to do it.

[EagleMark]

No losers here! Only learners! :thumbsup:

And I don't know if that is your issue? But it sure seems likely...

[sherlock9c1]

Yeah, the police history is a double-edged sword. One the one hand, the car was very well maintained. Engine internals were spotless. On the other hand, there was random wiring in the trunk, bolt studs from equipment racks still there, the headlight harness had been wirenutted back together and the headlights would blink over bumps (not kidding!), the trunk light wiring is dead (no idea why), and the TCC has never locked on its own since I got the car (I wired in a manual switch - the PCM inputs specific to TCC all seem to be working okay) [EDIT - turns out a lousy tune caused the no TCC lockup - a stock tune had the TCC working perfectly]. So yeah...

I'll try tightening up the ALDL connector pins. EDIT - ended up buying the Arduino module from the uber cheap thread and building my own benchtop harness for $15 in the chip and a set of junkyard PCM connectors.

[bigstevo]

I replaced a stock 95 lt1 5.7 Impala motor with a 383 stroker, ported vette heads, 58mm throttle body, 30# injectors, MSD, 268/278 cam A4, and hooker headers. Tunercats was used on the pcm. I get a code 43 and it wont idle. Do I need an esc module for an F body? I cant get it to run right and I need some help. It will fireup and die. If I unplug the maf sensor, it runs, but is too rich.