injector scaling

[sprattzvx]

hi all,
just remembered reading this;
"On some later model PCMs you can use the injector monitor feedback wire and connect a wideband to have it displayed - some vehicles work fine while others do some funky stuff to the inj scaling. Not sure on the VX, will have to check."
can anyone give me a basic description of injector scaling and its function/affect on a/f ratio.
thanks,
ken.

[Holden202T]

what it does is it use the injector line voltage to detect if the alternator is failing, so as the volts drop it offsets the injector pulse width to keep the AFR where its supposed to be....

VL400 has modded a heap of factory bins to use the battery voltage input into the pcm for the injector line functions so that then frees up the injector line wire to be used as a wideband input.

the issue is if you leave it as it is when you go lean the computer will try to offset the tune to make it richer cause all it sees is low injector voltage, so this then means any wideband reading you get is going to be wrong and you'll never get a decent tune!

see this thread for the info and modded bins - https://pcmhacking.net/forums/viewtopi ... itor#p7149

[VL400]

And the VX should be fine with a standard bin, but make sure you leave the fault code handling enabled for code 57 - you actually want it to get a fault so the code substitutes in regular battery voltage to use for the injector voltage scaling.

[sprattzvx]

what it does is it use the injector line voltage to detect if the alternator is failing, so as the volts drop it offsets the injector pulse width to keep the AFR where its supposed to be....

VL400 has modded a heap of factory bins to use the battery voltage input into the pcm for the injector line functions so that then frees up the injector line wire to be used as a wideband input.

the issue is if you leave it as it is when you go lean the computer will try to offset the tune to make it richer cause all it sees is low injector voltage, so this then means any wideband reading you get is going to be wrong and you'll never get a decent tune!

see this thread for the info and modded bins - https://pcmhacking.net/forums/viewtopi ... itor#p7149

ok just had a quick flick through the topic, and i feel like a dick for not picking this up earlier . ive had dramas with choppy a/f ratios and always rich first gear a/f since having the wideband. it seems i cant correct these probs using any modifier tables.bogs badly in first with wot a/f in the 10s. this maybe the gold right here.
im on a ddrj based tune, so i can use vl400s modified ddrj hsv tune and carry over my values right?

[sprattzvx]

And the VX should be fine with a standard bin, but make sure you leave the fault code handling enabled for code 57 - you actually want it to get a fault so the code substitutes in regular battery voltage to use for the injector voltage scaling.

Too fast for me, disregard my last post then. I guess ill keep hunting down the issue as i get the fault injector monitor line failure so i guess the system is resorting to batt voltage. Ive never adjusted fault handling im guessing its on by default?
Thanke for the info guys.