Date: Sun, 12 Apr 2015 09:19:52 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Idle Stabilizer System Delete. Cause Bog Off Idle?
In-Reply-To: <CAB2Rwfh86v0G6C_83+JXHnGnHHh_sqeHTo0289pMFOXi7HdFAA@mail.gmail.com>
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Bogs off idle are often a fuel delivery or mechanical problem. Excessive valve deposits, poor injector spray patterns and even worn valves/guides are common culprits. Unplugging the throttle switch will completely remove that as possible issue as the only time it will cause a problem is if it does not open fast enough when the throttle is opened causing the system to go into fuel cut off while trying to accelerate. In my years of repairing Vanagons I have only replaced three air flow meters and all of them were tampered with. Having the idle control unit unplugged has an effect on the temp 2 circuit. That sensor is shared with the ECU and ICU.
Dennis.
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Neil N
Sent: Saturday, April 11, 2015 5:44 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Idle Stabilizer System Delete. Cause Bog Off Idle?
Hi all.
This is for an '88 2.1 WBX with Digifant. The idle stabilization valve and control unit are currently unplugged. (see below).
However. If: engine systems are working correctly, IS system is connected, no other loads are on engine (AC, PS, heater etc.), when accelerating from a dead stop, does the throttle switch act as an input? i.e. if that input were missing, would this cause an occasional bog when accelerating from a dead stop?
I would think it doesn't make any difference given that the IS system should only affect the engine at idle, but then I have to wonder if there's a transition of sorts that happens when accelerating from a dead stop. i.e. at idle, air that is bypassed into intake plenum via ISV is closed off as the throttle opens. (throttle switch input?)
Regardless if engine off (ign. on) or "1" wire connected or not, engine running, the valve draws far less than the ~ 420 mA spec. Like around 130 mA VAC. The valve buzzes and I can blow air through it when it's operating. The engine runs ok otherwise but has the occasional minor bog accelerating from a dead stop. The worst bog so far, was during a trip in Harrison Lake area here in BC. While traveling back out of camp, we pulled over on a hill. When I went to accelerate from dead stop up the hill, the van took some time before accelerating.
Accelerator pedal about 1/2 down made no difference. In a second or two, the engine "caught up" and accelerated. I can't see how the idle stabilization valve would figure into this though.
FWIW, my local parts guy pointed me towards the Audi 5000 as a possible parts source for a used valve. I'll search more on this, but found this page interesting:
http://vnc.thewpp.ca/stuff/bentley/ep0niks.ctech.ca/vw/eva2/FU01/ch6.3.2.html
Via a linked page there, I see mention of 2 and 3 pin valves. I don't know if all 2.1 WBX digifant engines have this, but the ISV connector on my '88 has a 3 pin housing with only 2 pins being used.
I would think a CIS-E ISV is harder to find than the Vanagon part but it may suffice?
Neil.
--
Neil n
Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca>
1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy>
1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/>
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