Astro Van PCM was--->Running a 305 with '747

[Ludis Langens]

"Kurek, Larry" wrote:
> 
> This is an 88 4.3 TBI engine, FWIW. It is NOT a 747, but probably
> a derivative...:
> 
> ECM: 1227137
> Cal Code: FJD  also had 8515 on the chip.
> 
> So...any thoughts? Will 747 calibrations work on the ECM? I just need to
> change the backup chip and the main PROM and away I go...right?

Nope.  Someone changed ECMs in your van.  The 1227137 is a 1986 4.3 only
ECM.  It is a predecessor of the 1227747.  To use any '747 chips, you'll
need a real '747.

I'd be interested in seeing a dump of the FJD chip.

> How do I
> select a V8 vs a V6 with this ECM? The wiring diagram doesn't show a
> cylinder select pin I ground or leave open...

For TBI, there is no cylinder select.  The injector(s) fire with every
reference pulse.  The ECM hardware doesn't care about the number of
cylinders.  Only the software in the PROM needs to know so that it can
calculate engine RPM from the reference pulse interval.

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


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