scratching my head on this one.. 1991 kodiak no start

[cookie 70]

I'm going to disagree with the statement that the 19186079 is a replacement for 16147525. Form what I can figure out, the 19186079 is for 1989 ~ 1990 Topkick. GM used the same 4K chip for many different computer part numbers, but each computer part number always used a different definition file. I recommend using a .bin file for the 19186079, if the ECM wiring is the same 19186079 vs. 16147525.

What are the main differences?

[dave w]

I'm thinking the main difference between the 19186079 and the 16147525 is obviously the hexadecimal address in the chip and the associated electronics inside the computers.

For example,
1987 ~ 1991 TBI computer 1227747 uses definition $42 vs. the 1992 TBI computer 16146299 uses definition $99; both use the same 4K chip. The programming hexadecimal code is very different $42 vs. $99 and likely different electronics for things like the Injector Drivers, IAC, TPS, Knock Sensor, and others.

It would be a VERT BAD Thing if somehow a 1227747 computer chip was installed into a 16146299 computer and vise - versa.

Basically installing a 16147525 chip into a 19186079 would be considered a VERY BAD Thing too.

[cookie 70]

i see what you mean, i lucked up and finally found the proper ECM from a heavy duty salvage yard up north (im down in the bible belt) and they are gonna ship it in the morning.

until then i am going to focus on the other issues and report back ASAP.

[cookie 70]

GOOD NEWS!!!

The ECM i ordered from Active Truck Parts came in today, and that fixed the problem! Apparently there is a certain type of ECM for these big trucks '91 and newer..
I sent my Driver side Fuel tank off to a local body shop to be cleaned and relined inside while i have the truck down (slight rust inside), so i should have it back next week hopefully.

Very big thanks to Dave W and Steveo for their inputs, comments, and suggestions!

I sincerely hope that anyone with an issue like or close to mine can benefit from this thread!

[1project2many]

Basic information to help with diagnosis:

The ignition module will fire the coil without a working ECM. Checking for spark while cranking only tells you the coil and pickup coil is working and that the ignition module is partly working.
The ignition module will send a pulse to the ECM for each spark made at the coil.
The ECM will use pulses from the coil to fire fuel injectors.
If you install a noid light at the injector and spark tester on the coil wire you should see noid light blink when spark tester sparks. The "netres" or backup fuel hardware will make this happen even if the calibration in the eprom is bad.