Something stupid??? I HOPE!!!

[Blownrunner]

Correct me if this is false, but I believe I read that the later years cars' ECM's can be used in the earlier cars but not vice-versa.

So you should be able to use an ECM from a 91-95 car, right?

[mike100]

Originally Posted by Blownrunner

Correct me if this is false, but I believe I read that the later years cars' ECM's can be used in the earlier cars but not vice-versa.

So you should be able to use an ECM from a 91-95 car, right?

I have heard that is true, but never personally tried it.

[XfireZ51]

Originally Posted by mike100

I have heard that is true, but never personally tried it.

Actually it has been tried by Haibeck and myself. Any ECM can be used w any year car. The prom however needs to be for the correct year.

N.B. the 90 prom does not have an on-board knock sensor, so although any year ECM will work for a 90, the prom will need to be specific to the 90. It is possible to remove the Knock Filter circuit from a 91-95 prom however.

[Dynomite]

Originally Posted by XfireZ51

Actually it has been tried by Haibeck and myself. Any ECM can be used w any year car. The prom however needs to be for the correct year.

N.B. the 90 prom does not have an on-board knock sensor, so although any year ECM will work for a 90, the prom will need to be specific to the 90. It is possible to remove the Knock Filter circuit from a 91-95 prom however.

I just yesturday asked Marc.....regarding Marc's Chips Calibration AYBKG version #4 for '90 LT5's and Calibration BFXBG version #2 for '91 LT5's.

Are these two chips you create interchangeable at all? In other words can one put the BFXBG version #2 chip in the 90' Z?
Or the AYBKG version #4 chip in the 91'Z?

Marc responded.....

They are not interchangeable and if you did interchange them there would be a check engine error for no power key wiring with BFXBG in a '90. There would also be a knock sensor check engine code. The full power mode would not be available with AYBKG in a '91. Also, the knock sensor would not work.

[XfireZ51]

Originally Posted by Dynomite

I just yesturday asked Marc.....regarding Marc's Chips Calibration AYBKG version #4 for '90 LT5's and Calibration BFXBG version #2 for '91 LT5's.

Are these two chips you create interchangeable at all? In other words can one put the BFXBG version #2 chip in the 90' Z?
Or the AYBKG version #4 chip in the 91'Z?

Marc responded.....

They are not interchangeable and if you did interchange them there would be a check engine error for no power key wiring with BFXBG in a '90. There would also be a knock sensor check engine code. The full power mode would not be available with AYBKG in a '91. Also, the knock sensor would not work.

Yep.

[GOLDCYLON]

According to DOM a 95 ECM will work on a 90 91 92 93 94 and of course a 95. A 90 ECM will not work on a 91 92 93 94 or a 95.

He said the issue was they are backwards compatable if its at least a year newer than your car however not compatable forward.

This surprised me as I thought the difference was only at the PROM level between the years as the ECM for the LT5 platform was the same.

I trust DOMs opinion as he is the tuner master, but I will admit I was surprised by this. GC

[XfireZ51]

Originally Posted by GOLDCYLON

According to DOM a 95 ECM will work on a 90 91 92 93 94 and of course a 95. A 90 ECM will not work on a 91 92 93 94 or a 95.

He said the issue was they are backwards compatable if its at least a year newer than your car however not compatable forward.

This surprised me as I thought the difference was only at the PROM level between the years as the ECM for the LT5 platform was the same.

I trust DOMs opinion as he is the tuner master, but I will admit I was surprised by this. GC

GC,

At one point I may have followed the "urban legend" on LT-5 ECM compatibility, but last year I gave Marc my 92 ECM to test forwards and backwards. He also did the same w 90 and 95 ECMs. That thread can be found here.

http://www.zr1.net/forum/showpost.ph...70&postcount=1

ECMs are fully interchangeable. The issue, and this may be where confusion comes from, has to do w the prom. The 91-95 proms have on board KS circuits, while the 90 prom does not. If you cut the KS circuit board from a 91-95 prom, it can be re-programmed for use in a 90Z. However, a 90 prom, without the KS circuit, won't work for a 91-95Z.
Also, you cannot swap the calibrations year to year. With the exception of the 93-95 MY, each year ZR has a unique calibration mask. And there is an "A" version of each mask. Hope that clarifies things.

[GOLDCYLON]

Originally Posted by XfireZ51

GC,

At one point I may have followed the "urban legend" on LT-5 ECM compatibility, but last year I gave Marc my 92 ECM to test forwards and backwards. He also did the same w 90 and 95 ECMs. That thread can be found here.

http://www.zr1.net/forum/showpost.ph...70&postcount=1

ECMs are fully interchangeable. The issue, and this may be where confusion comes from, has to do w the prom. The 91-95 proms have on board KS circuits, while the 90 prom does not. If you cut the KS circuit board from a 91-95 prom, it can be re-programmed for use in a 90Z. However, a 90 prom, without the KS circuit, won't work for a 91-95Z.
Also, you cannot swap the calibrations year to year. With the exception of the 93-95 MY, each year ZR has a unique calibration mask. And there is an "A" version of each mask. Hope that clarifies things.

And there we have it. Thanks for the followup