Date: Sun, 12 Jul 2009 16:07:47 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: 91 Westy, idle problem
In-Reply-To: <13340009.9315.1247422461912.JavaMail.mcneely4@127.0.0.1>
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The idle control valve rarely goes bad. Sometimes the idle control fails but usually it will fail so there is a low idle or no idle boost. The idle control is a current pulse device that is normally closed with current applied to open it to boost the idle when needed. It is fairly easy to trouble shoot with the right equipment. Usually idle speed issues really start elsewhere.
The connector at the end of the idle valve should disconnect easily. Push the metal clip down and un plug it. Remove it check to see that it is almost closed. Block of both hoses and start the engine. If it is idling fast the valve and controller is not the issue. In fact on a cold engine it should have trouble idling. Check the ignition timing and try to set the idle speed around 800 with the valve still blocked off. Next look for vacuum leaks and a check the mixture control by measuring O2 sensor response.
In addition to the idle bypass screw on the throttle housing, you may need to check the throttle stop screw. The throttle plate may not be closing. Of course make sure you don’t have a cable or linkage issue holding the throttle slightly open.
After you get the idle under control with the ICV blocked, re-install it but leave the wire off. Again start the engine. Should be the same as with it blocked. If not, valve is probably bad. Broken spring or it is stuck open. If good, reconnect the wire. Should be a slight idle speed increase. If it runs away next step is to check wiring to the temp 2 sensor and the speed feedback (ignition coil). If either of these signals is bad ICU will up idle speed. If al checks out good and you still have a high or run away idle then most likely you have a bad ICU. You can also test the current and duty cycle of the ICV. Final setting should be around 130mA or 20-50% duty cycle under normal conditions. I like to set base idle speed around 900 rpm which leaves valve closed except for warm up or AC/PS support.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Dave Mcneely
Sent: Sunday, July 12, 2009 2:14 PM
To: vanagon@GERRY.VANAGON.COM
Subject: 91 Westy, idle problem
Well, many, many have queried and prescribed regarding this. My 2.1
idled way too fast, sometimes. A good mechanic said (as have many of
you) idle control valve (he called it idle air controller, but it was
the same beast). I left the van with him, asking him to do all usual
"tune-up" things like plugs, wires, rotor, distributor cap as well. He
did those, but only cleaned the icv, telling me that a new one cost
$550, that there were only two available in the U.S., and it would take
him several days to get one. I found one on-line at United Auto Parts
for $222. Has anyone had any experience with them? Are their parts any
good? I haven't ordered it yet. He did not mention the idle control
unit. I found that it costs another $280 or so. I drove the van 30
miles, all seemed well. But after reading all the past posts, I thought
I'd set the idle myself, following instructions several have given.
I found two significant things as I attempted to do so: (1) The
electronic unit on the end of the icv is very difficult to remove, and I
was afraid I'd break it. How to remove it?? (2) Looks like my
mechanic had simply turned the idle down to the lowest level the set
screw will go to. At that position, my van is idling at about 1100 rpm.
That is, in fact, why I was going to set it myself. But, it is as low
as it will go, and I cannot disconnet the icv anyway.
So -- do I need an icv, and an icu, one or the other or both? The icv
does hum (or has a very slight vibration that I can feel).
Any help appreciated.
David McNeely
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