Something stupid??? I HOPE!!!

[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.

[scottfab]

Originally Posted by yzpilot

Can't ever thank Mike enough!!!! SO to my relief, as Mike mentioned, she is alive! Felt so good to take it for a drive! So as Mike mentioned, the ECM was definitely the problem. Soooooo....anyone out there have a ECM for a 91 laying around they want to unload? Or anybody have recommendations as to the best person to send this off to for a rebuild?? Thanks for all the help guys! And again, Mike, can't thank you enough! Sleep will be good tonight! And good call on the beer! Might have found my new favorite brand! Lol!

Have you inspected all the pins going into the box?
Ideally to isolate further you'd need to install the suspect bad
ECM (with known good chip) into a different car.
Also looking carefully at the mounting socket for the chip
is a good idea.
Just FYI

[mike100]

Originally Posted by scottfab

Have you inspected all the pins going into the box?
Ideally to isolate further you'd need to install the suspect bad
ECM (with known good chip) into a different car.
Also looking carefully at the mounting socket for the chip
is a good idea.
Just FYI

My ECM ran his car properly
His prom worked fine in my ECM

I didn't have the opportunity to swap his ecm into my car, but my feeling is the injector driver is toast since other functions and communication are ok. I didn't have a scope with me. At this point it would be good to source a spare and possibly check into seeing if the bad one can be repaired.

[scottfab]

Originally Posted by mike100

My ECM ran his car properly
His prom worked fine in my ECM

I didn't have the opportunity to swap his ecm into my car, but my feeling is the injector driver is toast since other functions and communication are ok. I didn't have a scope with me. At this point it would be good to source a spare and possibly check into seeing if the bad one can be repaired.

Sounds right. Pins are the most common failure (bent broke off) either
the tons of pins going in or at the chip socket. But I've also seen issues with the big multi-pin sockets going in, such that one ECM appears to work and another not. It's a function of whether the socket is pressed hard in and how the wires behind it are routed. That is how I came to have a spare ECM

[yzpilot]

Scott...I checked all the pins on the ECM and the chip socket. I don't see anything out of the ordinary. All the same length and none look broken, bent corroded etc. Of course I couldn't get lucky enough for it to be simple!

[scottfab]

Originally Posted by yzpilot

Scott...I checked all the pins on the ECM and the chip socket. I don't see anything out of the ordinary. All the same length and none look broken, bent corroded etc. Of course I couldn't get lucky enough for it to be simple!

Too bad

[XfireZ51]

If the motor starts and runs w another ECM, are there any codes? I'm assuming you are using the stock prom in the borrowed ECM, correct?
Do you get the single SES flash when key ON? With scantool connected, have you checked all sensor values at key ON, not w motor running?
If not, you need to establish that all sensors are working nominally then move on from there.

[batchman]

Originally Posted by mike100

Somebody's car is running again (on the loaner ecm)...

It is really good to hear that plugging in an LT1 ECM did not fry other things, and now we have a documented symptom of that supplier error.

Now if we could enlist one of those module repair guys on eBay to study up on these ECMs....

Thanks,
- Jeff