Need help with my LT1! out of ideas - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

TimJackson · 09-11-2025, 08:43 AM

I have a 1997 LT1 swapped into an '84 C10. The engine and transmission were in the truck frame when I purchased, it so I decided to stick with it.

After five years of rebuilding the truck it is finally time to drive it and work out any bugs.

It idles fine to start with, then it will begin to run really rich. If I try to drive it, it hesitates and stumbles and will backfire. I have true duals and the passenger side bank 2 is running rich.

It has a new painless wiring Harness and starts fine. Here is what I have done so far and checked with a scan tool.

The map sensor and Maf are new, along with coil. On the scan tool, they are operating within specs. Map is at 14 at idle and goes down with throttle. Maf is around 1.6. The O2 sensors upstream are fluctuating between 0.1 and 0.9, sometimes a little higher on Bank 2. There are no downstream O2 sensors. Bank two is definalty moving more as I assume the ECU is tring to compensate for the rich condition.

I pulled plugs and they look as you would expect for running rich and only have a few hours of total run time since installed, mostly idling.

Check and rechecked for vacuum leaks and do not find any. Check pcv valve.

Pulled fuel rail and didnt see any leaking injectors.

The computer is pulling fuel from bank one but adding to bank 2 for some reason.

Thoughts Thank you in advance.

joshnmn · 10-02-2025, 11:19 AM

There’s a chance the O2 sensors are bad. I had one go south while I was tuning it and it drove me crazy.

Otherwise, might just need a tune (fuel tables cleaned up).

gtstorey · 10-02-2025, 11:24 AM

LT1's are known to have pretty bad split trims.

What is the fuel pressure doing?

09-11-2025, 08:43 AM	#1
TimJackson Drives: 1997 Camaro z28 Join Date: Sep 2025 Location: michigan Posts: 1	Need help with my LT1! out of ideas I have a 1997 LT1 swapped into an '84 C10. The engine and transmission were in the truck frame when I purchased, it so I decided to stick with it. After five years of rebuilding the truck it is finally time to drive it and work out any bugs. It idles fine to start with, then it will begin to run really rich. If I try to drive it, it hesitates and stumbles and will backfire. I have true duals and the passenger side bank 2 is running rich. It has a new painless wiring Harness and starts fine. Here is what I have done so far and checked with a scan tool. The map sensor and Maf are new, along with coil. On the scan tool, they are operating within specs. Map is at 14 at idle and goes down with throttle. Maf is around 1.6. The O2 sensors upstream are fluctuating between 0.1 and 0.9, sometimes a little higher on Bank 2. There are no downstream O2 sensors. Bank two is definalty moving more as I assume the ECU is tring to compensate for the rich condition. I pulled plugs and they look as you would expect for running rich and only have a few hours of total run time since installed, mostly idling. Check and rechecked for vacuum leaks and do not find any. Check pcv valve. Pulled fuel rail and didnt see any leaking injectors. The computer is pulling fuel from bank one but adding to bank 2 for some reason. Thoughts Thank you in advance.

10-02-2025, 11:19 AM	#2
joshnmn 2&THEHIT Drives: 5th Gen Camaro; 5th Gen Ram 3500 Join Date: Mar 2018 Location: Garner, NC Posts: 1,103 View My Garage	There’s a chance the O2 sensors are bad. I had one go south while I was tuning it and it drove me crazy. Otherwise, might just need a tune (fuel tables cleaned up).

10-02-2025, 11:24 AM	#3
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,450	LT1's are known to have pretty bad split trims. What is the fuel pressure doing?