I was reading Summit the other night and Dr. Overdrive was recomending an 85 ECM. He wrote that the ignition curve was better in ECM for 85 TPI than in ECM for 86-89 TPI.

I have alwais heard that the 85 ECM was inferior and I should uppgrade to 86 or newer.

Who is right?

Nonni

 

Think about computing power growth over time! Compare capabilities and power of a 1985 PC with todays P4 units. Though machine control is a different ball game than desktop computing both have improved over the years.

The '85 ECM is slower and has less EPROM size than later units, though a particular curve may be more favorable.

Each change in ECM part number brought new features and better overall engine control capability.

 

HELL NO!

The 85 ECM is junk. I'm in the process of replacing mine with a 165 (86-89) style, as have many others before me. The 85 computer is very primitive and makes modification difficult. With a 165 ECM you can burn your own proms to make the timing however you want it.

 

I have an 85' ecm and it is also junk

 

Thats EXACTLY why you came to the right place for your thirdgen modding / learning needs.

Seriously, the world as a whole couldn't be misinformed of every aspect of making GM computer controlled cars work. There are way too many people who all they know and believe are kludge fixes for everything. For example, mayb the 85 ECM does have a hot spark curve in it. Nevermind that you can't even tune it w/ a commercial bin editor, and that it's GMs first atempt at TPI management, and was dropped after just one year so it must have some glaring defect compared to the 86-89 ecm.
Misinformation like that is around everywhere. You did the right thing by checking in here. Countless people just read these boards w/o ever even posting. I'm sure those same folks also have summit catalogs, and a fewe were prolly wondering the same thing even.

 

the 85 ECM is junk, get a '165 MAF puter, run the ARAP bin ($32) code and have fun having power to tune. If you really have a stout engine, converting to a '730 (90-92) ECM may be a better choice due to the restriction of the MAF, but is not necessary unless you are running a 383 or larger CI. Not to say a '165 won't work, just that engines of that size will max out the MAF in airflow.

 

The ARAP bin is from 1989, which is $6E code. 87-88 is $32B code, and 86 is $32 code. And yes the 85 computer is junk. I wonder why Professor Overdrive would say such a thing.