No, when I said it could have been a replacement, I did not mean the E8TZ that one is the wrong ECM. Like you said.

I meant the F0TF-12A650-KA with the 1989 printed circuit board date in a 1988 truck could have been an ECM that replaced the original.

 

There should not be a Diode in the pin 57 path.


/

 

When he said “Funny thing about the computer matching a 1988 with V8 engine, it says 1989 on the circuit board”.
He was talking about the E8TF-12A650-AE2B and not the F0TF-12A650-KA.

 

This isn't what my board looks like. There's a half inch long trace that has pin 57 on one end and a diode on the other. The component is black with a gray stripe, the silkscreen on the board has a diode symbol, and it labels the part as Z1, all of which indicate a diode.

Where are you guys getting the schematics? I'd like to check them out. It's hard to find the right stuff with a google search because you're subject to whatever crazy things people say when they post the thing you're looking for.

 

Got it... I still did not mean the E8TF was a replacement. I will still follow along in the background.

 

The diagram in post 17 above is just a excerpt from this diagram posted on the Internet.
This is that diagram:


/

 

Rob, Did you figure out anything on the smoke/truck?

 

The computer smelled like circuit board smoke, so it was clearly coming from the computer rather than anything else under the dash, so we decided to order a computer. It should be here in a couple of days. I'll let you guys know how it turns out.

I'm half expecting some other problems with sensors, but if the former owner was trying to run it with the wrong computer I can see how this may be the only problem.