Hello, I am new here and searched around, but did not find an answer. I am looking into purchasing an older (1987 or earlier) Suburban, preferably 4X4. It looks like Chevy and GMC started putting Engine Control Modules (ECM'S) in Suburbans in 1983. I was wondering exactly what aspects of the Suburban those early ECM's controlled? Was it purely for fuel injection regulation, or were there other aspects that they controlled as well?

Thanks for any info you can provide.

 

most likely only fuel metering and rich/lean adjust.