Problems with Haltech F7 at high RPM's

[Doug Yip]

> 
> stop me any time if i'm wrong....  I am assuming that the injectors fire
> 1.5 times per rpm, ie. it takes two revolutions for all cylinders to fire
> once....
> 
> 7800 rpm  *  1.5 cyls....
> 
> = 11700 injector pulses per minute....
> 
> = 195 pulses per second
> 
> = .195 pulses per millisecond
> 
> = 1 pulse every 5.128 milliseconds
> 
> and you say 5 ms is 75% duty cycle ?
> 
> actually 3.846 ms pulse width would be 75% duty cycle at 7800 rpm for a 3
> cylinder 2 stroke engine.....
> 
> or am i wrong somewhere.....
> 
> This would mean the reason for it working on the test bench and not on the
> road would be because of the additional load on the engine.  On the test
> bench with no, or little load, the injector pulse width would not be as long.
> 

Injectors are batch fired once per rev.  At 9000 RPM this is 150hz, or
6.67 ms max per injection.  75% duty cycle = 5 ms.  Problem seems to be
that we're feeding Haltech normal tach signal of 3x/rev.  Will try to
change this to 1x, then change divisor on Haltech.

Douglas A. Yip
Digicon Engineering Inc.
http://www.digiconeng.com