Date:         Sun, 12 May 1996 20:21:19
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         EXPRES@gnn.com (RON SALMON)
Subject:      Re: Cold Start Valve



>Recently the engine began cutting out roughly 1-2 minutes after
>a cold start. The engine would restart but only after cranking
>continuously for about 20 seconds. The engine starts and runs fine
>otherwise. The problem only occurs when the engine is cold
>and not hot. I haven't yet run a diagnostic test yet 
>but am guessing one of the following:
>
>a) cold start valve - not sure what the connection might be here;
>b) aux air intake - it is either not closing or closing too early;
>c) gas pump relay - again a guess;
>d) idle stabilizer.
>

Another possibility is the Temperature Sensor.  After a short 
warm-up period, the temp sensor is supposed to vary resistance 
based on head temperature, causing the computer to alter the fuel 
mixture.  If the temp sensor is defective or not properly grounded, 
the motor will shut off after it warms up. I have seen this happen 
a few times on '75-79 busses, either because of a bad sensor or a 
bad harness connection to it.  I imagine that the fuel injection on 
an air-cooled Vanagon isn't much different.

I would try disconnecting the sensor and connecting an alligator 
clip directly  between the wire going to the sensor and ground.  If 
the motor runs this way, this means one of two things:  the sensor 
is bad, or by richening the fuel mixture (which is what happens 
when you ground out the sensor) you compensated for a problem 
elsewhere.

Also, I would thoroughly check all fuel injection system grounds.

You could try swapping the dual relay ("gas pump relay"), as you 
mentioned, but I believe it is time rather than temperature 
controlled, so this is inconsistant with the motor running 1-2 
minutes just when it is cold.  The cold start valve could be 
leaking, and thus flooding the motor, but again I don't think your 
symptoms are consistent with this problem.  (This again just from 
emperical experience with F.I. problems; I'm not an expert.)

Good luck,
Ron Salmon