Haltech (the bad word)

[Rex Weatherford]

----- Original Message -----
From: "Bruce Plecan" <nacelp at bright.net>
To: <gmecm at diy-efi.org>
Sent: Friday, December 29, 2000 10:37 AM
Subject: Re: Haltech (the bad word)


>
> This is a blind guestion.
> What are you trying to actually do?.

I want the GMECM to be able to compensate for AC compressor load, PS load,
(run IAC if possible).  I want the GMECM to run the tach and gauges, start
safety switch, ABS (if it even cares about ABS) and all gauges.  I want a
programmable way to adjust spark and fuel and have data logging ability to
track things.  I don't have cruise control or an automatic tranny to worry
about.  But I would like to retain my stock gaunges and AC would be nice.
These things are in a fantasy setting.. I'm willing to comprimise!  (such as
tossing AC all together in the name of a stable idle and performance)

> While the sensors are the same, they might use different
> pull up resistors, and give confusing signals to each ecm.

Definately a concern....

> 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.

OK.

> 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.

Yes the aftermarket ECM "can" be used in closed loop with a standard 0-1
volt O2 sensor.  I'm a little confused with your answer?  Is the answer that
I can't get the GMECM to stay in closed loop mode if I use one sensor for
both?  What if I used two, one for each?

>
> 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.

If that is possible I'm open to all suggestions, but I dont' know of any...
It's for a Quad4 and I have found practically nothing to help me.  I've
think I have found the SA and VE tables, but I'm just guessing in the dark.
I have found 18 possible tables between $040-$756 on a Quad4 chip and then
gave up because I was finding tons of stuff, but have no way of knowing what
they are without a disassembly, and I have no idea how to do that.  I was
doing good to be able to decipher HEX code...  So now I feel rather lost and
I am trying to weigh the options before proceeding in either direction.

> For the price of the new Haltechs ($1100) you can buy alot.
> Bruce

I have found the E6GM for less then $700 and I may be able to better then
$600 with some connections.  Diacom Pro alone is $480...  The E6GM will do
everything I want except for IAC compensation for loads (such as AC),
possible loss of gauges, and some other things I am forgetting... but
nothing I can't live with if I have to..  I'm want to do this right.  I feel
that I could probably just slap a fuel pressure regulator on the car to get
enough fuel at WOT (but not necessarily everywhere I need it) and hope that
the SA and BLM's can adjust enough or don't cause problems..  But I'm doing
a somewhat radical engine change (ported head, different cams, up from 212
duration to 226).  I will need to change timing, fueling, RPM limit, and the
idle may be all but impossible without a separate 0 TPS fuel/ignition map
(which Haltech supports as well as WOT)  I also want to get this done by the
month of May and tune it by the end of June.  (is that pushing it?)

So I have a few legitimate problems right?  What about just being able to
swap the 2 different ECM's for everyday driving and racing?

Thanks for the help!

Rex

----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org