new member....backfire prob.

Ludis Langens ludis at cruzers.com
Thu Nov 19 20:08:25 GMT 1998


David Curtis <spdrcr at flash.net> wrote:
>   I have a '67 Camaro with a '97 LT1.  I run a '95 Z28 computer.
> The copmuter has had the airpump and passkey programmed out.
>
>   When I acclerate like I mean it, I get a good, single
> bang out the back end when I hit the clutch on the upshifts.
>   I notice it does this when ever I'm around 4k rpm and higher.
>
>  Also, if i let the car decelerate in gear..I get some not-quite rapid
> fire pops out the tail pipes.

It sounds like your Deceleration Fuel CutOff isn't working.  The ECM is
acting like it thinks you are in neutral.  Do you perhaps have an
automatic calibration in the ECM?  Or if you have a manual calibration,
the transmission gear ratio tables in the ECM don't match your actual
transmission.  Also, check that your VSS is hooked up correctly.

As to your last item, the Fiero V6 ECM has a real live software bug that
can cause the decel popping:  Acceleration Enrichment can turn on even
during DFCO.  This same bug might exist in your ECM.

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





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