[Diy_efi] 749 tweaks

[James Panter]

Bill  I've had so much trouble getting my twin turbo to run with a 749 it 
almost gives me a small bit of pleasure to see one of my mentors have some 
fruntration!!!   Good luck on the tune.        Jim Panter
----- Original Message ----- 
From: "Bill Shaw" <b.shaw at comcast.net>
To: <diy_efi at diy-efi.org>
Sent: Saturday, July 07, 2007 2:20 PM
Subject: [Diy_efi] 749 tweaks


> 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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