RB26 fluctuating idle/AFR, bad O2 sensors?

[koopsta]

Hey everyone,

Recently I installed a Nismo collector and Nismo 555cc injectors on my RB26DETT. I resized the injectors and installed a LC-2 wideband to monitor my AFR. I read on the forums that I was to take the injector latency (710) and times it by 2 (so 1420). I could not get the car to idle properly and found my AFR was at 9.9 to 10.2. No matter how much I adjusted my K constant and TIM the car would not improve. Well I had to drive the car regardless of this issue due to work. It ran, okay.

Now I have found out that I was not to times the injector latency by 2 and only entered 710 to the program. The car runs much better (AFR around 14.2 to 14.9) but that is just the problem. It will not settle and has a noticeable idle issue. It only jumps approximately 50 RPMS, but the health of the engine can be felt as unstable. This unstable AFR cannot be fixed no matter what I adjust. To include the LHS o2 jumps from 0.1 to 1.25 sporadically and RHS o2 is stays at 0 (idk if this is suppose to work as the RB has 2 o2 sensors). Also my AAC sits at 10% once at temp and the timing jumps from 20, 21, 22 degrees with the change in the idle. I do not know if this is because of the o2 sensor being bad and/or fouled plugs.

Could the overall issue be because I drove the car extremely rich for 30 minutes (I know that was a terrible thing but had no choice) and I fouled the plugs and both O2 sensors? Or is it my timing map (which I feel does not need to be adjusted)? The timing cells for my idle read below. Do I need to adjust that 25 to a smaller number to fix this maybe?

20 25
20 20

[Matt]

Closed loop does not function at idle on most ECUs (only at cruise). The latency should not have been doubled as you found out.

K constant/TIM should be adjusted so 14.7:1 at cruise (with near 0 STFT/LTFT trims) and you reach the second last column on full boost

So you only had idling issues since upgrading the injectors? Were they new, or if second hand flow tested?

[koopsta]

Secondhand and not tested. I currently live on an island in Japan and could not find a shop who does that. When accelerating the car feels smooth and normal. I got too focused on the idle issue, so I have not cruising and accelerating recordings.

I have been adjusting for 14.7, but it never stays stable. I will switch back to my stock 440cc injectors and see if the engine runs normal again. Update to come this weekend. I hope these injectors are not bad.

[Torque]

An island in Japan? Nice!

Anyhow .. are your injectors the yellow Nismo ones?