Hey,

Little background needed here.  I have an '87 Vanagon that's supposed to 
have the 2.1 w/Digifant.  However, the PO had a crapped out 1.9 w/Digijet 
installed when the original motor died, burned etc.

Since this was done, the setup in the engine compartment is a bit cobbled 
up.  With the help of Fast German Auto I now have a fully rebuilt 1.9, 
clutch, etc. and she's running beautifully.  However, when the engine is 
idling and the AC is turned on she wants to die.  Now the reason for this 
is that the PO removed all the Digifant idle compensator circuits when he 
pulled the 2.1.  However, it looks as if the vacuum hose setup is from 
what the wonderfully thick Bentley Vanagon manual says is an "Early 
Digijet" set-up meaning there's no IDLE SPEED BOOST VALVE for the AC.  
Well, I'm going to call VW on Mon. and see how much the valve is.  If 
it's reasonable enough, I'll be buying from them, if not I'll be scouring 
junkyards.  

NOW, MY QUESTION IS THIS:  WHERE does this elusive IDLE SPEED BOOST VALVE 
live on the Vanagon.  If any of you listees out there could take a look 
at your AC equipped'83, '84, '85  DIGIJET (not Digifant) Vanagon and tell 
me where it should be I would be much obliged.  
If you have the Bentley manual look on pg. 24.24b to find out how it 
hooks up.  However, if you do not have the manual then track down one of 
the wires that comes out of the AC compressor (1.0 Black (on my Digijet 
motor with a Digifant AC compressor(don't ask) it is 0.5 Red/Black)) and 
leads to a small boxish object with 1 or 2 vacuum hoses coming out of 
it. The 2 vacuum lines should hook up to either side of the Auxiliary air 
regulator. Where is this thing on your vehicle.

What the IDLE SPEED BOOST VALVE seems to do is when the AC is turned on 
it opens the valve and in conjunction with the auxiliary air regulator 
lets more air in bypassing the throttle valve altogether thus causing the 
fuel injection to compensate for the added load of the AC compressor 
preventing your motor dying on you at idle with the AC on.

I know some of you hardcore types will tell me to unhook that wimpy AC.  
Well, I drove cross-country (coast to coast) in a rusted out '78 Westie 
with no AC with daytime temps in Arizona reaching a record 125 F and let 
me tell you, it was an adventure.  So I've paid my dues and the next time 
I have to do it, I'll do so with the AC blazing away and a stupid grin on 
my ugly face ;).

Thanks to everyone who has answered my previous postings. And beware all 
those out there looking to buy that 2.1.  From what I understand, so few 
were brought over that if the motor has been rebuilt, chances are it was 
replaced with a 1.9.  Buyer beware!!

Thanx,

Perry

'87 Vanagon (w/1.9 Digijet)
'81 BMW R80 G/S w/ '90 Paris/Dakar pkg.
'83 Moto Guzzi LeMans III
'77(?) Laverda 1200 Triple (soon to have SFC livery)

                                            no1ukn0@netcom.com