Yet another injector timing thread

[LS_Coyote]

Hello all,

After having thought that I have figured out the Gen4 injection timing, I am pretty much at nill again. General understanding is that:

EOIT = Boundary - (Normal ECT + Normal RPM)

My car runs great if I set my Boundary at 470* the Normal ECT to 0* at operating temps and the Normal RPM to 0* at and below 896 RPM yielding a 470* EOIT at idle. If I change my Boundary to 520* and the Normal ECT to 50* at operating temps, while keeping the Normal RPM at 0* at and below 896 RPM, which also should yield an EOIT of 470* at idle, the car runs horribly.

This leads me to believe that there is quite a bit more to EOIT tables than assumed so far, or the definition that we think assume to be valid in the formula above is simply not correct. Another thought I am having is that most other vehicles define the EOIT at x* BTDC compression, while we define it at x* in a cylce of 720 crank degrees where 720* would be TDC compression. Could this be where the bug is hiding?

Any input or experience with this is greatly appreciated, especially if someone from HPTuners could chime in with some more info on these tables

[RobZL1]

Change your makeup pulse to "none" and see if that changes anything when you are at the 520 setup. When you move the boundary in to 470 and zero the ECT and RPM, you are effectively eliminating the makeup window. With the 520 setup, you still have time between 470 and 520 to fire makeup pulses if deemed necessary by the ECM. Set it to "none" at 520 and see if it runs the same as the 470 setup.

[07GTS]

dont worry about the maths adding up as it wont cos there is a little more going on then we can see, just let your trims or wb tell u how idle is with getting fuel into the chamber then u have your base point then u can adjust it for rpm on the boundary table after that, normal rpm zero it, normal ect set to stock and lower/raise it to get your trims richest, boundary have all 520 for tests then once u move normal ect to good u can adjust the boundary after that for the higher rpms

[LS_Coyote]

Change your makeup pulse to "none" and see if that changes anything when you are at the 520 setup. When you move the boundary in to 470 and zero the ECT and RPM, you are effectively eliminating the makeup window. With the 520 setup, you still have time between 470 and 520 to fire makeup pulses if deemed necessary by the ECM. Set it to "none" at 520 and see if it runs the same as the 470 setup.

Interesting! I'll definitely give this a try and report back. Thanks!

[LS_Coyote]

dont worry about the maths adding up as it wont cos there is a little more going on then we can see, just let your trims or wb tell u how idle is with getting fuel into the chamber then u have your base point then u can adjust it for rpm on the boundary table after that, normal rpm zero it, normal ect set to stock and lower/raise it to get your trims richest, boundary have all 520 for tests then once u move normal ect to good u can adjust the boundary after that for the higher rpms

Yea, I am sure also that we can't see everything that's going on in the background... I'll try this as sort of last resort, but what worries me is that I want to understand what is going on and not getting it right by luck without knowing when really my EOI is happening. It would be nice if one could at least log the EOIT in the scanner to verify these numbers.