Haltech (the bad word)

[Bruce Plecan]

>  I'm going to ask a question and I know most won't like the word..  What
> about the aftermarket ECU's like the Haltech?  Can I have that unit take
> over the fuel and spark control, but leave the GM ECM there and wired up
to
> take care of the other things?  What kind of problems would I likely run
> into?

This is a blind guestion.
What are you trying to actually do?.  You want the ecm to control what the
CCP, and TCC?.   While the sensors are the same, they might use different
pull up resistors, and give confusing signals to each ecm.  Like on my ecm
bench, I wound up having to use ganged pots to get two ecms to *see* the
same thing.   Even things like min TPS can get sorta confusing.

  I would think that I might end up with some BLM type codes (if there
> are any) because the computer will loose the control to effect the spark
and
> fuel, but I would fool it into thinking that the injectors were still
there
> (resistors?)  I'm not sure on the spark portion of this problem..  I will
> also loose the knock sensor from what I currently understand and would
like
> to create one of the KS lights that I have heard talked about so that I
can
> have that as a back up when tuning to catch a timing problem..

If the ecm you want to piggy back to, expects a AFR correction read back
from the O2, the whole idea crashes right there.  No hac, no way to stay
closed loop, usually.

> I have gotten some info from a person that did this and I am waiting on a
> response from them for more details, but I wanted to get your feedback
too!
> I think you guys are the experts on the GM units and could probably think
of
> more problems that I might have then I can.  I have a time table for my
ECM
> changes and would like to get everything worked out by May so that I can
> tune all June (or before)  I have a gathering to go to in late June and
> would like to be running well...
>
>  I'd like to talk off line with someone with experience with any
aftermarket
> units..  Sorry this is a bit off topic of GMECM's.  I really want to have
a
> customizable ECM, and for me an aftermarket unit might be a better
financial
> route since I don't already have all the hardware equipment that is
required
> for what I am trying to do now. (laptop, Diacom, chips, burner, eraser,
mask
> id, etc...)  Not to mention the dissasembly work etc...

I had a Haltech GM6E, and after seriously looking at it, sold it.  There are
just too many downsides.  Running two ecms is possible, but means maybe
having to run two of all sensors.
  You'd long term probably be way further ahead to convert to some ecm that
is hac'd and follow that route, if possible.
For the price of the new Haltechs ($1100) you can buy alot.
Bruce
>
> Thanks and I appreciate all the help and knowledge that you guys have
given
> me!
>
> Rex

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