GM ECM injector driver capacity

[Bruce Plecan]

-----Original Message-----
From: Jennifer and Brock Fraser <fraser at forbin.com>
To: diy_efi at esl.eng.ohio-state.edu <diy_efi at esl.eng.ohio-state.edu>
Date: Monday, August 24, 1998 12:30 AM
Subject: GM ECM injector driver capacity


>Does anyone know what the injector driver capacity is on GM ECM's?

On the Howell four barrel Holley conversion he wires the the injectors
to two groups of two.  Meaning 2 in series, and then in parrarellelllel
witha second group, BTW they are Peak+Holds.

 To be
>specific, I'm curious about the 165 ECM.  I see that on a multi-port V8
>application, all 8 injectors are batch-fired by 2 outputs.  Is it possible
>to attach 8 more injectors to these two outputs (series, parallel??) to
fire
>16 injectors simultaneously?

So far, in my limited testing the outputs of both the 165 and 730
while they use two terminals, they tie to one driver.  Also, several
other folks have said this.  On the one chip I have had run on the
730 it does fire all 8 at the same time, once per crank revolution.

  Info pertaining to the 730 ECM would be good
>as well...  The injectors would be high impedance (12-14 ohm) ones just
like
>the stockers.
>
>If this isn't feasible, what would it take to make the GM driver(s) also
>trigger another external driver for the extra injectors?  Again, the desire
>is to fire the second batch of 8 at the same frequency and P.W. as the
stock
>batch of 8.

As testament to the the gm ecms I've run two IACs off the stock
ecm that only had one, with not problems.

If you can set up a resistor network for what you want to fire, send it
to me, and I'll bench run it,  but you'd have to stand good for replacing
the ecm if it dies,  usually they cost me $50-60.

You might consider using two ecms.
>
>
>Thanks,
>Brock
>
Cheers
Bruce