ECM Fault?

[Ludis Langens]

"Akselrud, Boris" wrote:
> 
> What I found by
> looking at the signal with an oscilloscope is that there is an additional
> abnormal impulse approximately 0.1 .. 0.3 ms wide in between the normal
> impulses opening the injector. This abnormal impulse comes and goes,
> perfectly corresponding to idle rpm fluctuation. Even when I step at the
> accelerator pedal, up to a 2500 rpm I can see the abnormal pulses and again,
> they are not always there, they come and go with 1..2 sec interval.

These pulses are the result of "acceleration enrichment".  Your ECM is
sensing the TPS opening, and/or the MAP pressure increasing, and/or it
is opening the IAC.  All three events will cause extra fuel to be
injected asyncronously of the normal injection.

The question here is - is the AE the cause of your unsteady idle, or is
the unsteady idle causing the AE?

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/