What is the CALPAK prom, and what does it do? Do all Fieros have it or only those sold in California?

If you're looking at the ECM I think the calpak is the little chip to the left of the EPROM.
It contains the Limp Home parameters in case your EPROM goes toes-up.

I think all of them have it. At least all of the 86-88 V6 cars do.

The Calpak is different from the PROM...

If you open the access panel on the ECM (V6 model) You will see the PROM.. (BIG CHIP ) right next to it (well close anyway) you will see a small chip. this is the Calpak...
What does it do? The CALPACK contains preset calibrations used by the system during "limp home" (backup) mode

So there you have it all you never wanted to know about it

-Darius

Edit: Dang he beat me to it.. as I was typing.. anyways 2 brains better than one?

[This message has been edited by Unltd1 (edited 03-21-2006).]

All GM cars of that era have a calpak prom - it contains the default values for the particular engine and transmission combination in the vehicle.

By keeping that data in a socketed PROM, GM could use the same basic ECM over many different makes and models.

Fiero V6 ECMs are the only one with a removable CALPAK...
( I just verified by opening a bad 84 ECM 4cyl and a good 88 4cyl ECM)

quote Originally posted by Unltd1: Fiero V6 ECMs are the only one with a removable CALPAK... ( I just verified by opening a bad 84 ECM 4cyl and a good 88 4cyl ECM)

Hi Just curious here---does that include all GM cars of that era ??? Thanks...

no problem in curiosity... ( I've seen lots of cats , so we can spare a few here and there )

I wouldn't bet that it would be all GM cars in the general time frame, but at least we know for the Fiero that is the Case (well might be nice to check out say the 85-87 L4 ECM to be sure)..
I wouldn't put it past them to have used the logic elsewhere, maybe only V6 and V8 ECMs had a removable CALPAK,

IIRC the later V8 Fbody's had them integrated into the "PROM" (the special looking prom was longer ) from maybe 86 up..

I have no way, outside of opening many ECMs to know for sure (maybe when I retire )

When I had the 84 and 88 ECMs open, I wondered where the "limp home" data is stored... It has to be in there somewhere. its just not removable.
Bits,bytes and nibbles stored here and there OMG what is the world coming too!

-Darius