'7747

[Ken Kelly]

>>Are you interested in using a 7747, or an 8746, or???
The information for both ecms is available.  Are you planning a swap from
one ecm
to the other?

I'm interested in the '7747 as a retrofit to the '5550; I have an '82
Corvette. I'm trying to get all the wiring down; it has the two A.I.R.
valves, which concerned me.

> 1. C8;PSPS - what the heck is this? (Power steering?) What does it do? How
> does it work? (It's labelled as an input..)
closes when power steering system is pressurized.  Consider it a load sensor
to
help prevent stalling.

Hmm.. could this be wired to something else that tends to load down the
engine? I assume it just bumps up idle by X amount..? If so, where is that
amount determined (or is it preset, not in the PROM?) Or does it just bring
idle up to where it should be, if this switch is set?

> 2. A2;A2OUT - listed elsewhere as "A/C Control" .. how is this wired in
with
> the A/C? What does it do? Are you supposed to wire your A/C switch into
the
> ECM, and the ECM to the compressor (so the ECM controls the compressor?)
I'm
> only assuming that it cuts the compressor off at higher throttle settings
so
> you get more power? (y/n?)

>>It's not used in all applications.  If you're installing a 7747 in a
system with
"self contained" a/c, it's not necessary to connect this.  Although it might
be a
nice touch to make a "professional" job out of it.

Okay, so I could wire it in as I described (switch to ECM, ECM controls
compressor) and it would cut off the A/C .... at what point? Is it
determined by load, or by throttle position? I like the sound of that, so I
don't have to shut my A/C off if I punch it.. (I know, sounds like I'm
lazy!) BTW, what do you mean by "self-contained A/C" ?

>>If you haven't already found it, there are wiring diagrams there for both
ecm
types.

That's where I found the diagrams.. :D

Thanks again VERY much for the reply; just these little tidbits have helped
tremendously.

Ken


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