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Re: Injector opening time



On Mon, 7 Aug 2000 bcroe@juno.com wrote:

> I wonder if someone could clue me in on the part of
> fuel injector pulsewidth that is lost to just opening
> and closing, no fuel delivered?  What I mean is if
> an injector pulsed for 7 ms had an effective open 
> time of 5 ms, then a 12 ms pulse (2 ms opening
> plus two times 5 ms open) would deliver exactly
> twice the fuel of 7 ms
> 

I was tuning in my SpeedPro ecm using Delphi 50 # injectors and
the Typhoon would hardly start and idle. Had to tell the software that
inj were 40 # units to get to idle using reasonable VE numbers and a
starting a/f of 13 to 1 in a/f target table. I had a 1.0 ms opening
time in the configuration. Turns out that was too SHORT. When I raised
the opeming time to 1.5 ms, it got real rich and I could go back to
nominal (normal) settings for inj size etc. The Delphi injectors are 
supposed to be pretty linear but that 0.5 ms change in opening time made a
giant difference in a/f. ( As measured by the SpeedPro wideband sensor and
a separate NTK I have- they agree)

regards,

frank parker


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