With my tech2 I can move the iac valve and the rpm gets close to up until 1800rpm. When I command the idle to 2k, the iac can't do it. Is that normal? I didn't think it was but then I read somewhere that that is out of the iac range. But then went be able to test it that high?

 

Why be able to test that high

 

Well no start at all with my 369 ICM. Must be junk. Haven't had time yet to go through the flow charts for my codes. Did receive my new distributor because I stripped one of the holes for the distributor cap in swapping all these ICMs. Before I installed this distributor, I bought a brand new ac Delco 1943 ICM and mounted it on the new distributor with thermal paste. Same symptoms, actually seemed better with a cheap ICM from Amazon.

 

Well, seems like I'm talking to myself, still running bad. Showing codes 42 ignition bypass fault and 43 knock sensor.
Followed the repair schematic for code 42 and found I had no continuous on the I believe ckt 424 which I believe is the ignition disconnect for setting base timing. What's interesting before I checked for continuity on this wire I unplugged it while the truck was running to see if it reacted. It did it was definitely just idling on base timing, kinda rough. I plugged it back in and it didn't seem to change back so I shut the truck off, I believe I restarted it and it was ok? I don't remember. But anyway when I found that wire was open, I temporarily ran a new wire and now I have continuity from the 4 plug on the ICM all the way to the ecm. Started the truck, ran like crap. Actually worse than ever. I now can't get over like 2200 rpm or so.
Thought maybe that wire being open, fried my new ac Delco ICM because I followed the rest of the diagram for that code and it checked that either ckt 424 was open, or bad ICM. Checked continuity on that wire and is still good. Swapped out that ac Delco at summit and installed it, same exact thing.
Do you guys think it could be the crank sensor? I noticed while cranking I get 0 rpm on my tach until it starts. Or do you think my computer is at fault?

 

Ok, another confused and confusing update. I unplugged the wire I ran to get continuity on ckt 424, the tan wire you unplug to set timing and now it runs way better, almost to the point where there may not be a problem anymore. So how does that make sense? I do not have continuity on that wire. And I know it's not running on base timing because like I mentioned, you can hear the difference when I unplug the wire that doesn't even reach the ecm.....