peak-n-holds

[Bruce Plecan]

-----Original Message-----
From: Mike Pitts <mpitts at emi.net>
To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
Date: Saturday, March 20, 1999 10:42 PM
Subject: Re: peak-n-holds

I'd venture a guess it's also, got alot to do with the injectors closing
faster.
It would be interesting to hook up a good scope, and actually look at the
injector's signal.  Having the same chip, and two ecms you should see
(at least I'd imagine), a marked difference in the opening spike, and
closing
"waves".
Bruce
   I'm jealous.........


>>So to change to Peak+Holds was just a simple R+R of the transistors?.
>>I was under the impression that it took a "board" with at least a sense
>>resistor, and some support electronics
>
>It wasn't that simple, but close.
>
>For these particular drivers, a sense resistor is not required.
>They are the same type of driver as the Motorola MC3484S4-2.
>It's a rather self-contained driver, with the only external additions
>being a resistor on the supply voltage and a zener between the
>output and ground.
>
>On the 1227148, there's already a zener in the original circuit,
>shared by all the drivers, isolated by other diodes.  I had to find
>a source for the supply voltage, but that was easy by just following
>a trace and double checking with a meter.
>
>I installed my brand new completely modified ECM a few minutes
>ago and the car fired right up.  Is it possible that the car would idle
>smoother from this change, or am I just imagining things? I'm
>thinking that at the super low pulsewidths required for these big
>injectors at idle, the flow is more uniform with the peak current
>yanking them open harder than the saturation drivers did...just
>a guess.
>
>-Mike
>
>