Date: Fri, 27 Nov 2009 08:26:22 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: revving idle --> 83 Westy gasser
In-Reply-To: <34475.66733.qm@web56408.mail.re3.yahoo.com>
Content-Type: text/plain; charset="us-ascii"
Most likely one or more of the "Basic" settings are off and/or you may have
a week O2 sensor. Here is the cause.
When the throttle is closed, (switch is being made) and the engine for any
reason goes above 1,300 rpm the injectors get turned off. As the engine
speed falls the injectors turn back on back the O2 sensor is ignored for 30
crank revolutions. If the uncontrolled mixture is rich enough for the engine
to drift up to a fast idle at 1,300 rpm the injectors shut off and cycle
goes again.
Things you need to check:
Throttle, Is it closing properly and consistently?
Auxiliary or warm up air regulator? Does it work and is it getting power?
Take it out and test it.
Distributor, Do all the advance mechanisms work? Is the vacuum chamber good?
How about the mechanical advance? Does it work freely? I have seen the shaft
sieve from lack of maintenance. Yes, you need to occasionally oil that felt
under the rotor. Turn the rotor and look down, see if it moves in relation
to the lower shaft and pull on the springs in there. Test function with a
timing light. Set basic timing to proper spec. Over advancing to improve
performance will add to your woes here.
O2 sensor, is it working? As an upgrade consider going to a 3 wire sensor
such as used 86 and later. Also cover it to keep the wheel spray off it.
Idle mixture, adjust the air bypass screw if needed. Hopefully your AFM have
not been tampered with. With the engine warm and O2 sensor disconnected set
so that you have ~.4 volt at the O2 sensor with idle speed at 850-950 rpm.
No higher!
This should take care of your idle woes. It is common for the idle l occur
after a warm restart. This is due to the warm up regulator sometimes causing
a fast idle when the engine is still warm enough to go closed loop. It
should return to a normal idle quickly.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Matthew
Sent: Wednesday, November 25, 2009 1:07 PM
To: vanagon@GERRY.VANAGON.COM
Subject: revving idle --> 83 westy gasser
folks, I'm stumped.
83 1.9 bare bones stock engine. Runs like a champ with ~22mph religiously.
But at idle, it 'revs' or cycles rpm.
i've replaced (From a well running engine, or new at time)- both temp
sensors, replaced and re-adjusted both throttle body position switches,
ensured no leaks in the air intake (post AFM), replaced the idle controller
(bypassed it too), inspected as many wires that i can get to, big honking
grounds from head to block to head to tranny to body...
I think it is the throttle body stuff- maybe the wires? Anybody have
suggestions, other than tracing the wires back to the ecu, and cutting and
splicing?
Or suggestions of something else to look at / into?
thanks
matt
"may the four winds blow you safely home"
