JAZZA

I have a 85 and would like to change the ECM to a later model so it can be flashed. What are my options can one from a 87-89 fit. Tranny is a stick and has been changed to a ZF6 so no ECM hooked to it. Thanks for any input you can give me.

rodj

Nothing that works with your engine can be "reflashed"
The later TPI ECM's still have a memcal (chip ) the same as your 85 ECM that needs to be reprogrammed
or replaced with a EPROM that can be taken out and reprogrammed.
However you an buy this device
http://www.moates.net/ostrich-2-0-the-new-breed.html

that effectively allows you to reprogram ( reflash ) the tune from a laptop; even while driving

Most would advise swapping in the later '165 86 - 89 TPI ECM anyway because of it's better support and it's faster operation , as well as getting rid of the impossible to find , expensive MAF burnoff module only used in '85 cars

Mainly involves repining your ECM connectors and adding the later MAF relays
See
http://www.eecis.udel.edu/~davis/z28/ecm_swap/

JAZZA

Thanks for your replay, it answered most of my questions. If I change the Ecm, I than can order a programed chip from a vender that would work with my car?

rodj

Yes
usually you fill out a order sheet with your engine mods on it and they tailor a tune to suit
NB ; this is reprogramming or " getting a tune " ; not " reflashing"

Reflashing a tune is only done on a later model computer where the memory is permanently inside ( flash memory )
and can't be removed for reprogramming. '94+ LT1 and LSX engines have that setup

JAZZA

Thanks again, will go this route.

Cliff Harris

The main problem with going to a later ECM with flash capability is that the newer ECMs had many more inputs (such as multiple O2 sensors), so you would have to fake all those unused inputs to keep from setting error codes.

I think there are also more outputs, so those would also have to be simulated. The quad drivers need to have a load or they raise an error with the microcontroller.

The other way to get around this is to modify the firmware code to ignore the extra inputs and outputs, but that would be a HUGE job (unless somebody has already done it).

The communication methodology with the dashboard changed also, so that might be an impossible hurdle to get over. For example, the VSS output from the transmission goes to your dashboard and from there to the ECM. On later cars it went to the ECM first.

rodj

Least of your worries.( most can be programmed out )

Later PCM's have completely different inputs for spark control so you need to accommodate that
You need a crank position sensor and a reluctor wheel for those inputs to use a LSX PCM

http://www.eficonnection.com/eficonnection/24x.aspx

or a Optispark if trying to run a LT1 flash-able ('94-'97 ) PCM