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Date:         Tue, 11 Jun 1996 10:39:20, -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         TVCR50A@prodigy.com ( MICHAEL G BENTHIN)
Subject:      Re: HELP, 78 westy, 2L FI trouble (high

Arnold Schultz  tried everything to reduce idle (1700) on 78 FI engine:


I'm mystified too- have 78 with 167,000 mi on original engine (and I mean
original- ONLY thing done besides tuneups was pushrod tube seals and I
pulled it at 150,000 to prophylactically replace clutch disk which still
had a mm of lining before the rivets!  My only FI problems related to the
wierd right angle connector coming out of that flat little box on top in
center of engine (hidden behind distr.)- had a crack and was letting extra
air in.  You MUST be getting a source of extra air or extra air/gas!
   The official troubleshooting guide VW put out lists the following as
causes of fast idle-


1.Throttle valve not closing - guess you checked this.
2. Idle adjustment- if fully turned in, check:
3. Aux. air regulator not closing-block hose-if it drops, it's dead wire or
 bad regulator>>>  doesn't drop >>>
4. Deceleration valve not closing ()block hose between it and intake air
distr- if idle drops, replace decel. air valve. No speed drop>>>>>
5. Fuel pressure in ring main too high (26-31 psi, check with gauge), could
be due to leaky hose between intake air distr. and pressure regulator, or
pressure regulator bad, if pressure OK,>>>>>>>>
6. Ignition problem- excessive advance, sticking spark control ?


Sounds like you checked most things- possibly you are getting a combination
of unmetered air leak and leaky injector(s) causing this?
 I'd also check for secondary air sources like oil filler pipe, dipstick
cap, valve cover gaskets, crankcase ventilation hoses, and if present, PVC
valve CLOSED at idle.. If there is an EGR connection (I've never seen an
intact one!), exhaust may be fed back at idle speed- manual says to check
pipe between egr valve and intake air distr. should not get hot (mine's
been blocked off forever) -if there & blocked, make sure this pipe is not
leaking. Other sources include throttle valve shaft and between throttle
valve housing and intake air distr.  Also, how do you know idle adjustment
screw is doing what it should? Let us know!   MB in NJ
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