Engine Rebuilt: Ported Heads/CAM - Bank-1 and Bank-2 Fuel Trims Unbalanced?

Tiny
JOHNKUEHNE
  • MEMBER
  • 2005 DODGE RAM
  • 8.3L
  • V10
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
8.3L viper engine rebuilt with new ported heads Greg Good/JTS Venom (Valves are oversized to 2.02 intake and 1.60 exhaust) and new Cam (629 lift intake / 628 exhaust lobe at 114°). When a base tune (created by a professional tuner) remotely, in preparation to drive to dyno for full tune. A problem was noted with the short-term fuel trims. “ It is adding a lot of fuel to Bank-1 and subtracting a lot from Bank-2”. New Bosch O2 upstream sensors already installed on Bank-1 and Bank-2 (same issue the previous O2 sensors ). Even though Up O2s have unique connectors... To verify not swapped, one was disconnected and validated to be noted not responding on the correct bank in HP tuners software. A previous issue with two vacuum leaks were addressed to where now intake manifold pressure is 5.1-11.6 psi (3K rpms to idle). The engine was rebuilt with new spark plugs/wires, new OEM coil packs and all 10 injectors were cleaned. Fuel pressure verified 60 psi on Schrader valve on bank 2 rail (fuel comes in on bank 1 rail) both idle and under load (3K rpms). No leak on intake noted: sprayed stater fluid along runners of intake manifold plenum and no change in idle noticed. What would be the next troubleshooting step? I have HP Tuner and Bi-directional scanner available to test.
Tuesday, March 4th, 2025 AT 6:26 AM

7 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I was thinking it was swapped o2 sensors, but it sounds like you thought of that as well, are there any exhaust leaks? This will cause the issue as well. If not, I would remove the spark plugs to see if any are bright white or dark in color compared to the rest of the plugs, please upload an image of the spark plugs so I can see.
Was this
answer
helpful?
Yes
No
Tuesday, March 4th, 2025 AT 12:24 PM
Tiny
JOHNKUEHNE
  • MEMBER
  • 27 POSTS
Verified no exhaust leaks at headers coming off heads or downstream. But removed all 10 spark plugs, picture attached. Should I clean the spark plugs and reinstall, or buy new spark plugs? What to check next?
Was this
answer
helpful?
Yes
No
Wednesday, March 5th, 2025 AT 12:27 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yep, one bank is rich, can I ask if this engine has catalytic converters? If so, the dark bank might be clogged. Can you confirm the cat is not? This guide might help us:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please go over this guide and get back to us.
Was this
answer
helpful?
Yes
No
Thursday, March 6th, 2025 AT 8:39 AM
Tiny
JOHNKUEHNE
  • MEMBER
  • 27 POSTS
The vehicle has test pipes, which it has had for the past 3 years. What is the next troubleshooting step? Can I clean the plugs and reinstall them?
Was this
answer
helpful?
Yes
No
Thursday, March 6th, 2025 AT 10:32 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yes, you can but let double check the oxygen sensor locations, here is the wiring diagrams so we can make sure the primary oxygen sensors are not swapped. The left sensor will have the brn/yel and the right one will have the brn/vio wire. Check out the diagrams below.
Was this
answer
helpful?
Yes
No
Friday, March 7th, 2025 AT 9:02 AM
Tiny
JOHNKUEHNE
  • MEMBER
  • 27 POSTS
The O2 upstream sensors were verified to be connected to the correct Banks (see attached).
Was this
answer
helpful?
Yes
No
Tuesday, March 11th, 2025 AT 5:05 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Lets do a compression test on each side of the engine to help make sure the camshaft timing is correct.

This guide can help:

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.
Was this
answer
helpful?
Yes
No
Tuesday, March 11th, 2025 AT 12:40 PM

Please login or register to post a reply.