Date:         Mon, 13 May 1996 14:35:34 -0500 (CDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Gerald Skerbitz <gsker@lenti>
Subject:      Re: Re- Continuing Engine Troub

Everyone else must have thought so too because I didn't get any replies.
:-)

On the other hand, there needs to be a test to find what I found (O2
sensor wire shorted (?) with the shielding for that wire (said shielding
being tied to pin 6 of the ECU connector and from there to the Air Flow
Meter)
You are probably right that it might not be a good idea, but it WAS the
key to finding the problem.  In the future, I will recommend checking
impedance between pin 5 and 6 on the ECU connector with the ECU
disconnected and the Air Flow Meter connector disconnected also. 


On 13 May 1996, Harvey Chao wrote:

> Gerry - you requested folk to :  With everything else connected and the
> ignition off disconnect the O2 
>     sensor wire.  
>  Connect the Digital Voltmeter up to the ECU O2 wire (not the O2 sensor
>     wire) in resistance mode.  
> Check:  I would like to know what resistance you get on this. "
> 
> I have a modest concern about this.  In essense you are probing a very high
> impedence input channel with an ohmeter.  Depending upon the meter and
> resistance range selected on the meter, such action imposes a voltage into
> this input channel that may not be compatible with the circuit under test. 
> Without know the components, meter, and circuit,  there is some potential risk
> of damage in this process.

Of course, in my case it wasn't a high impedance channel -- it was 20ohms.
Which was the problem.   :-)

I'm cc:ing the list so the concerns are heard.
--
Gerry
Gerald Skerbitz <gsker@med.umn.edu> U of MN Med School Admin 6-5379
Home St. Paul,Ramsey County,Minnesota, USA