Injector Duty Cycle ?

[DrX]

Immediately after kickdown the PCM knocks the throttle back down to 20% then lets it go back to 100%. All of this takes place within 1-2 seconds. It must be responding to input from some sensors to trigger this. As it is in OL/SD(no O2s or MAF) it must be related to RPM, MAP or something to do with the trans, right?

FP is steady since I installed the returnless system and the PCM has no input as to what the FP or AFR is anyway. Although AFR does rise during the sudden throttle transition. Misfire logs all show 0 counts.

[DrX]

Is the rev limiter anticipatory? Could it be responding to the rapid rise in RPM on the downshift? I will have to try disabling it completely.

[DrX]

Well I set the ETC Rev Limiter to disable and just in case that didn't work, changed the engine overspeed allowed time to 1 sec from 0 so the PCM wouldn't make any hasty decisions.

Problem solved! So something must be triggering the Rev Limiter early.

[DrX]

Thought it was safe to plug the narrow bands back in now. But as soon as I did that I am seeing constant INJDC variation between the banks again even though it is still in Open Loop/SD! Only 22 channels being logged. This the reason I unplugged them in the first place. It was the only way I could get the expected congruent INJDCs in Open Loop/SD. Something happens when the PCM sees input from the O2s even though trimming is disabled.