Hello all! I’ll try to keep this short, but I’ll start with a bit of background info. I bought a 1976 Chevy K10 with a 350 tpi out of a 1992 camaro awhile back. Didn’t run great but I’m in the mentorship stages of my career as a Chevy tech and was looking for a project. After a few weeks of driving it lost almost all driveability, pulled my plugs and the plug for cylinder 6 was toast. The plug was severely mangled, it had been beaten on badly. Pulled the head and determined motor was toast and replaced it with a reman. Replaced almost everything in the process.

When all was said and done I started it up and let it run for about 10 mins to ensure proper operation. To my disappointment, it ran like a one legged man. Decided to start with setting timing and idle speed. Had trouble setting timing due to fluxuating RPMs and determined something bigger was going on.

From there I determined that I’m most likely running lean on bank 2. Found exhaust from bank 2 is extremely hot and dark, while bank 1 is clear and cool. Headers on bank 2 get almost too hot to touch immediately after starting. Before swapping in the new motor I noticed that the exhaust from bank 2 was producing a lot of smoke on cold mornings compared to bank 1. I chalked it up to the hole in the #6 piston and the disgusting fuel injectors I pulled off the old motor. But both of those problems have been taken care of. I’ve got 45psi in the fuel rail and bank 1 seems to be operating normally, so that tells me I’ve got spark, air, and good fuel lines/rail/pump/injectors.

Tested at injectors #1 and #4 with a noid light and found the light to be bright and flashing, normal operation as far as I can tell. I should test all the other injector connectors, but sense this system is batch fire, and the bank 2 header feels to be a consistent temperature throughout, I’m not really sure if it would be worthwhile, and I don’t want to let it run for too long and risk damage to the new motor.

My gut is telling me the ECM is shot, but I don’t know how to verify this. Part of me just wants to buy an ECM and engine wiring harness and call it a day because evidence is telling me my problem is in one of those two things. However, that’s a pretty penny to spend blindly, and I know that I have the skill set to diagnose and pinpoint my problem.

Where should I go from here? Why am I running lean on bank 2?

In the mean time I am going to use the noid light on the rest of the connectors, test my injector fuses, search for a vacuum leak, inspect my plugs, and drink a beer. I didn’t do a great job at keeping this short, but thank you for reading!


EDIT: After spending some time kicking myself, I realized that bank 2 is running rich, not lean. I'm not sure how I overlooked that. I determined this by reading the plugs per Tuned Performance's suggestion. I found that the plugs for bank 2 are coated in a dry soot, while bank 1 plugs are cleaner and have un-burnt fuel on them. The passenger side exhaust is coated with soot as well. I go into more detail down below. I will hopefully be able to post some updates tomorrow!

I replaced my injectors, so hopefully they’re not clogged up already, but theoretically if I had plugged injectors would I have a higher pressure reading at the fuel rail? I have a gauge installed on the rail, so I’ll double check that my pressure reading is within spec. How would you suggest I narrow it down to cylinders?

Turns out I already have a heated o2, uses the o2 for a bronco, feeling kind of skeptical of that. Not very confident in really any of the wiring the previous owner did. I smoked out my intake last night and found a leak in the booster hose, and smoke was also dumping out of the IAC valve between the head and connector area, not sure if that’s normal but I went ahead and replaced it anyway.

The injectors i bought were from napa, I’ll check my receipts and double check who makes them, I just know right now that I got the OE equivalent. Was that a bad choice?

I pulled off the valve covers to make sure the TDC I used when I installed the dizzy was actually TDC. Looks like there’s a chance I was about 30 degrees retarded... I installed a remote starter and bumped the motor until cylinder 1 exhaust started to open, backed it off and put a zip tie into the plug hole, rotated clockwise until the zip tie stopped moving. Is that an okay method? Should I remove and reinstall the dizzy?