[Diy_efi] 749 tweaks

[DORENE MIRCHANDANI]

Bill,

It sounds like you are possibly idling in asynchronus mode and it's 
switching to synchronus mode when you get on the throttle.  I can't  imagine 
needing to idle at 4ms pulse widths in synchronous mode injector 
firing....especially with "bigger injectors".  My guess is due to the larger 
injectors (smaller bpw vs %egr value) it requires a smaller synchronous 
pulse width than the minimum sychronous base pulse configured(KAPLL).

Depending on your injectors, they may or may not be able to reliably fire 
small pulsewidths.  If they can, you can test by setting KAPLL to 0 which 
will keep you out of async injector firing mode.  You can also disable async 
by setting KQASPRMD to 0 rpm.  In my experience, I have not been able to 
idle in async as the transition to sync in anything but smooth.

Hope this helps.

Brent


>From: Bill Shaw <b.shaw at comcast.net>
>Reply-To: diy_efi at diy-efi.org
>To: diy_efi at diy-efi.org
>Subject: [Diy_efi] 749 tweaks
>Date: Sat, 07 Jul 2007 15:20:13 -0400
>
>I'm working on a cal for my new 5.0L 928 engine and I'm having some 
>trouble.  I've had this basic setup running pretty good for several years 
>and dozens of track days now - Porsche 4.7L V8 with LT1 throttle body, SyTy 
>ecm (1227749) running a max of 9 psi from a Vortech blower.  Recently I've 
>'improved' things - bigger 58 mm throttle body vs stock 48 mm,  bigger 
>cams, bigger injectors, extrude honed heads, headers, bigger exhaust.  I 
>started with the same bin I ran on the previous motor and dropped bpw vs 
>%egr a bit to compensate for the cumulative engine/injector changes then 
>tweaked F31E base VE vs RPM & Map, and  F30 base VE vs RPM to get it to 
>start and idle.
>
>It's starting and idling pretty good now,  but as soon as I touch the 
>throttle the injector pulse width goes from about 4 ms at idle to about 
>1.5ms. It spits & pops as long as I keep the throttle open and won't rev 
>past about 2k.  As soon as I close the throttle I see the injector pulse 
>width jump to 6 ms or so.   I've tried increasing the AE delta throttle and 
>AE delta map tables with no real change.  Any ideas why it's shortening the 
>pulse width when I crack the throttle?  Where should I look to  increase 
>the pulse width?
>
>Thanks,
>
>Bill
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