Date:         Sun, 5 Nov 1995 17:39:09 -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         SyncroHead@aol.com
Subject:      Re: cold start/idle problems with 2.1 digifa

In a message dated 95-11-01 16:25:48 EST, Porter_Fred%PAX9@mr.nawcad.navy.mil
writes:

>When I start my engine after it has sat all night (ie. a cold start) it will

>not stay running unless I keep slight pressure on the gas pedal.  It will 
>also stall while idling at a stop light.  This behavior continues until the 
>engine has warmed up, then it runs fine.
>
>I think this is because of a bad coolant temp sensor (sender?).  Since it is

>bad, the default setting is for a running engine and when cold the engine 
>requires a richer mix.  Without the input from the temp sensor the engine 
>runs as if it were warm (to lean) and stalls.

Since the operation of the temperature sensor is a variable resistance you
can diagnose it (roughly) by removing the temperature sensor wire.  When the
sensor is cold it has a high resistance and as the engine warms the
resistance drops.  You can create an artificially high resistance (infinite)
by disconnecting the wire.  This infinite resistance will be much higher than
a properly operating temperature, but the computer should be tricked into
thinking that the engine is very cold and richen the mixture.

G'luck!
Jim Davis
87 Syncro
88 Wolfsburg