1985/1986 Fiero ECM pinouts wanted.

[Ludis Langens]

Terry Kelley <terryk at foothill.net> wrote:
> Anybody have the 1985 and 1986 Fiero ECM pinouts. I have a copy, but it
> is not that readable. Any help appreciated.

It looks like your request has been covered, ...

I assume you are interested in the 1226869/1227170 V6 ECM pinout, and
not the 1226864 L4 pinout.  Either way, I've traced out the complete
schematic of these ECMs.  If you have any questions about what a given
pin connects to, ask.  (These tracings also apply to the 1226870 V6 MPFI
/ V8 TPI and 1226156 L4 ECMs.)

If your pinout data is from any sort of official source, beware, GM has
propagated errors.  In particular, be careful with the paired injector
driver outputs.  My factory service manual shows the wiring harness
grouping the outputs in a way that doesn't make sense with the actual
ECM circuit board.  I suppose I should ohm out a real wiring harness.

Also be careful with the ground connections.  Two of them are power
supply inputs into the ECM.  Several others are meant to be outputs to
sensors like the TPS.  The O2 and EST/Distributor grounds are actually
the inverting input side of a differential circuit.  Finally, the ECM
has several mode selecting inputs that can be grounded.  Many service
manuals simply show all of the above as chassis grounds.

               unsigned long BinToBCD(unsigned long i) {unsigned long t;
Ludis Langens     return i ? (t = BinToBCD(i >> 1), (t << 1) + (i & 1) + 
ludis at cruzers.com            (t + 858993459 >> 2 & 572662306) * 3) : 0;}