ECM basics

[belsie]

Are there any differences between stock ECM's ? Have picked up a couple as backups and used 1 recently to get running after bending a prong playing w/ chips. Car seems to be running fine but has lost some et's and mph @ track.
Same chip and no other changes so curious as to any ECM possible causes??
Thanks for any input.....................................

 

[RmvBfrFlght]

As long as the Service Number on the paper label matches, they are the same ECM. For an '86-'87 it is: 1227148

The replacement ECM(s) can be bad. The quad-drivers will go out. They run things like the TCC, waste gate, CCP and EGR solenoids. There may also be something like a single injector driver out. Can check that on a cold start with an IR gun on the tubes where they exit the head.

The large chip (EPROM) is likely different, and the small chip (CALPAK) may be different.

RemoveBeforeFlight

 

[belsie]

Thank you sir, all my extra ecm's have the 1227148 sticker but is it poss they were sent over the years to re-con and if so how do I test or confirm the items you mention?

 

[RmvBfrFlght]

For an injector driver it is as I posted, use an IR heat gun on the headers tubes close to the head.

For the quad-drivers a visual inspection can tell a lot. There are three q-driver chips on the lower board near the harness connectors. Most of the time when they go bad there is physical damage to the chip. Craters, holes, fried, cracked and so on will mean that the chip is bad.

RemoveBeforeFlight