mikez1

I've rebuilt my 2004 350z with forged internals, jwt S2 cams, new timing chains, etc. I'm running a treadstone / turbonetics kit so I upgraded fuel pump, injectors, and added a aam stage 1 return system. My VVT Solenoids are old(91K miles) but never really had issues in the past before the rebuild. I'm just learning how to tune using Uprev tuner so I am definitely a noob. I've only started the engine a few times and flashed the ecu for the first time. When I did some data logging to try to tune the k multiplier I saw:

1) Bank 1 as 0-0.5 deg advanced but bank 2 is -2.5 - 2 deg advanced.
2) A/F correction in Bank 2 is lower by 5% (Bank 2 is 76% vs bank 1 is 84%)

Any thoughts on why the difference in the advancement or why my A/F corrections are off?

Swaglife81

When 2 banks are off from one another with the one being in that perfect range. Gotta look at that other side. Some would say it's a vacuum leak on that side. Could be just 1 injector that's a little off. At idle vs 1500 rpms vs 2500 rpms is the fuel trims leveling out? Also a way to find non code throwing issues is chase the issue by swapping stuff from one side to the other. Swap 02 sensors and see if any changes happen. Good way to rule out possibilities to limit the problem area.

mikez1

So the good news is that I think the timing may have corrected itself after logging the last 1-2 minutes. I put the engine under load doing a couple short runs in my driveway(No insurance / registration / inspection yet). I revved the engine up to 5K rpm and looks like the issue could have been cam phaser being stuck till it received some oil pressure.

However, I still have a trim imbalance. A/F Correction bank 1 is leveling at 95-100 while bank 2 is at 82-89.

@Swaglife81, I'll try swapping WB O2s this weekend as see what happens.

mikez1

I've swapped O2 sensors, injectors, and performed a compression test. Not much changed after changing injectors and O2 sensors. I also re-gaped my plugs. My fuel trim is 90% on bank 2. I used a compression tester and am now seeing the following pressures:

Cyl 1: 140
Cyl 2: 140
Cyl 3: 145
Cyl 4: 130
Cyl 5: 141
Cyl 6: 120

With my 2 cylinders being off on bank 2 I am almost positive I've narrowed down the issue. So I may have issues with my valves not sealing or my rings not yet seated(likely). This is a brand new lowered compression rebuilt engine. I'm 90% plus positive that my rings were at the proper gap, my heads had a fresh valve job, but reused my stock valves. Would really like people's thoughts on if I should try to break in the engine, re-tourque the head, or any other advice given cyl 6 is off by 15%. Thanks in advance for your thoughts.

Mjsj16

Did you ever figure out your problem?