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

[Ken Kelly]

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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