[Diy_efi] 749 tweaks

[Bill Shaw]

My biggest problem this afternoon was from a completely unexpected 
source, the ignition bypass was open.  Once I plugged it in things 
started behaving much better (Doh!)

It ran good enough for me to take it out on the road.  Idle and very 
light throttle are much better,  I can accelerate slowly but it goes 
lean pretty quick once I start opening it up.  Still more work to go but 
definitely an improvement today. 

Thanks for all the suggestions and input.

Bill

DORENE MIRCHANDANI wrote:
> 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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