Injector Pulse Width.

[green]

|Hi All,
| I measured my pulse width at idle on an oscilloscope and it is
|1.2 ms. Yes I have 4 X 720 cc/min injectors. On a Diacom log it shows
|0.6 ms at idle. Why the difference ?

Could this be the Quasi asynch mode in the syty program? (you mention
promgrammer below, i assume you are using 7749 ecm and syty chip?)
I've used this mode, it does *seem* to work.  (seems to work =  i change
back and forth between exact programs, except with one has quasi asynch
enabled, one doesn't , and i notice a difference in idle quality)
It's supposed to use 2x the pulsewidth every other rotation, rather than
regularly calculated pulsewidth every rotation - for better injector control
at short pulsewidths.  FWIW, diacom showed no change in pulsewidth when
switching between QAS on and QAS off chips....

KAPLL/KAPLH are the thresholds in promgrammer to change to use this
function.


| I have been looking at the 'Promgrammer program' a little closer
|and want to know what effect changing KDISFS (Injector Flow Rate) loc
|328 in the memcal will do. I have read the GM Doc and it does not seem
|to mention KDISFS.

I've not seen it in the code at all.  I'm wondering if it's a value used for
MPG calcs used in GM test equipment??
Or a reference for whoever's tuning on that software program?

| I am wondering why the difference with true pulse width and what Diacom
|displays. Could KDISFS have some effect on the difference or is there a
|logical explanation.
|

Good question, doubt it's KDISFS. I'd like to hear that it is the quasi
asynch mode working, then we'd have some more faith in that ecm and diacom's
values  ;-)

Brian Green
91 Syclone #160