Problems with Haltech F7 at high RPM's

[Matthew Harding]

At 01:00  22/06/98 -0700, you wrote:
>> the injectors are probably running at 100%(+) duty cycle !, they
>> wouldn't
>> have even closed, and they'd be trying to open again......
>
>> What sort of injector pulse width (ms) is it trying to ouput at 7800 +
>> rpm,
>> under WOT ?
>
>> and is it running simultanious or sequential injection ?
>>
>
>Pulse width is being kept under 75% duty cycle (5ms).  Injection is
>simultaneous.  Looks like problem was with our particular Haltech unit
>(or revision) though.Thanks


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.

Matthew Harding
---------------

reply to any of these....

mharding at qonline.com.au
bernie at ronscomputers.com.au
bernie at browse-cafe.com.au