I have swapped a 02 LQ4 w/241 heads and an ASA cam backed by a th350 into an 85 C10. I really want this thing to run and I am at my wits end with it. I got it to idle on its own but there was a miss that I could definitely feel. When We were able to put the scanner on it we were gettting P0200 and P0300 codes(Injector Circuit Problem and Random Misfire)
Here is what we have done:
1. I moved the grounds for the PCM from the body to the motor. All of my grounds for the engine/PCM are now on 1 ground on the back of the motor. I have 4 grounds from the PCM (pins 1 & 40 on each connector), 1 for each coil bank and 02 sensor and 1 for the MAF/IAT sensor.
2. hooked up noid lights to the injectors and 1, 3, 2, and 4 injectors weren't lighting up.
3. I checked all the injectors for keyed 12v and they all had 12.3v
4. Next I checked the continuity of the injector wires from the pin for the computer to the injector and all of them had connectivity.
5. I also swapped the injectors around to see if the problem followed the injectors but I wasn't sure if it made a differnece bc I could un hook all plugs from 1 side and no matter which 1 i hooked up it seemed to run a little better. This is where I stopped bc I ran out of time.
After talking to a buddy about how the noid lights worked I have come to the conclusion that it probably isn't an injector issue but probably either wiring or the actual computer itself. After reading and researching I have found out that there are drivers in computer for the injectors but I can't find out which injectors go to which driver anywhere. If I knew that it would help out. I am not sure where to go from here and I am tired of chasing our tails. I followed everything on LT1swap.com to a tee.

 

I thought you had this figured out, I guess not? Anyway... when you check for continuity on your wires you need to wiggle the harness around to make sure you don't have a wire that has good continuity sometimes and other times not. Yoj also need to make sure that the wires you're checking don't have continuity with ground (shorted to ground) or power if it isn't a power wire. Check these while "massaging" the harness.
On a side note, have you replaced the spark plugs? Sometimes when first getting one to run, you'll foul out some and wont think of replacing them because they're new. I have personally done this, and new plugs was a cheap easy fix.

 

I will check them next time I am at the truck. I was thinking the same thing about wiggling the wires while checking the continuity.