Re: New to the group..

[Shannen Durphey <shannen@grolen.com>]

Ken Kelly wrote:
> 
> Hi everyone, I'm new to the group and I wanted to introduce myself.
Hi, Ken Kelly (#2). ; )
> 
> I'm working on a couple of projects, but my main focus is on the '7747 ECM
> (which is apparently the best hacked ECM so far.) I have a 1982 CrossFire
> 'Vette that I'd like to tune, but the 1225550 ECM is apparently more
> difficult to hack, so I opted to convert to the '7747 instead. (Per Bruce
> Plecan's suggestion.)
> 
> I have a few questions though; I looked at the website and found the pinouts
> for the '7747, but there are a few things I'm confused by:
> 
> EAC - Electronic Air Control? (What the heck is this?) What affects it?
> 
> ERVR - ???? What is this? What controls it?

These are in the DIY_EFI archives:
EAC= Electronic Air Control(yup, diverter
valve), and EVRV= Electronic Vacuum Regulator Valve for EGR
control. (why didn't they just say that??).
Notice that the circuit number and pin designation are the same for
EGR and EVRV?

Now they're also in the GMECM archives. : )


> 
> I have a solenoid-operated ram-air door in my hood, that is controlled by
> what's labelled as "load temp function 2" on the 1225550. The "load temp
> function 1" goes to the TCC. Is there an equivalent to the "load temp
> function 2" pin on the '7747? It's controlled by TPS% I believe on the
> 1225550. (I'm not totally sure of this.) Would the ERVR possibly be similar?
> (Whatever that thing is?)

Posssibly, sort of.  It's controlled by engine temp and MAP.  It might
be easy to change it to operate your solenoid, but EGR operation is
somewhat inverse to cold air door, ie it's not operating at low
map/high throttle conditions.  I don't remember if the crossfire uses
an electrical solenoid for the EGR valve either.
I might be tempted to try to use the a/c clutch control.  I think a/c
is stand alone on your car.

> 
> Is there a better diagram of the '7747 pinouts?
How much better do you need?  Are they incomplete or too blurry?
> 
> If anyone's interested in my project(s) - you can take a look at
> home.houston.rr.com/ken73 (no www) and it will direct you to my server at my
> house.
> 
Too cool.  Do you have info for the 5550 ecm?
Shannen
> Thanks!
> 
> Ken Kelly
> 
> ken73@houston.rr.com