'7747 & two A.I.R. valves - CrossFire retrofit

[Shannen Durphey]

Good idea, and great way to use the resources.

There's more than a dozen calibrations for that engine!  AKAJ/1147 is used in 1987+
1988 trucks w/ 700R4 trans and federal emissions, AMUR/0055 is also used in 87 and
88 trucks w/auto trans.  In 88 they're listed as pickup calibrations, but in 87
there's no distinction between suburbans and pickups.

Hopefully someone else can be more help with the air valves.  I'd need to see more
than an electrical diagram to understand which valve does what. Sometimes one valve
performs multiple functions.  There have been too many variations over the years. 
I don't remember them on a year by year basis, and I definitely don't remember the
name changes GM has applied to the different valves through the years.  

 Hmm...  Later factory replacement convertors for the 82 Vette may not have come
with the AIR tube.  There was trouble in the early days with the convertors failing
due to excessive heat.  With the 7747, emissions may be good enough that additional
air isn't required to light the convertor.  The xfire runs extremely rich at idle
and when cold with the OE ecm, the 7747 won't be this way.

You need a calibration for a 90=91 Suburban?  Well, let's go with federal
emissions, a/c, auto trans, 350, and 1/2 ton suburban.

  part no	bcc	superceded
 16139558   ASDT/9560     NO
 16139566   ASDU/9567     NO
 16130167   ANSY/0168     YES
 16132726   ANTA/2727     YES

ASDT and ANSY are for a 2.73 rear gear ratio, ASDU and ANTA are for all others.
Good luck.
Shannen

Ken Kelly wrote:
> 
> Duh. Kinda answered my own question, sorta. I jumped on CarParts.com and
> selected different vehicles that I knew used the '7747, and looked in the
> AIR/CAT replacement part section to see if the two valves were listed.
> (Yikes.. they're almost $200 each!) The '88 C1500/350/VIN"K" Suburban
> apparently had both valves. Going over to Ludis' C3 crossreference, there's
> over a dozen calibrations just for the "K" VIN.
> 
> I just looked at the two 1227747's I have that I yanked at the junkyard;
> they are both listed (externally, on the box) as AKAJ, yet one of them has
> an AMUR PROM in it (the other one actually has the AKAJ PROM in it.) They
> both came from 1988-1990-ish Suburbans, 350 TBI. (I can't remember what
> year, and I kick myself now for not noting it!) Apparently the '88 Sub used
> two valves, one being the AIR control valve, and the other being the AIR
> "diverter" valve. The '89, '90, and '91 Subs used an AIR control valve and
> an AIR "bypass" valve. (Which is which??)
> 
> The CrossFire schematic for the emissions shows an AIR "control" valve which
> is the main valve off the pump - it switches between the air cleaner or the
> second valve, called the AIR "switching" valve - which I'm assuming is
> probably going to be the "bypass" or "diverter" valve equivalent. (y/n?)
> 
> Also, Cannister Purge Solenoid is apparently used only on '90-'91 Subs.. so
> I need a '90-'91 Suburban PROM to start with.. any ideas?
> 
> Ken
> 
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