Date: Thu, 17 Jun 1999 09:38:46 -0700
Reply-To: Karl Wolz <wolzphoto@WORLDNET.ATT.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Karl Wolz <wolzphoto@WORLDNET.ATT.NET>
Subject: Re: Connector contact intermittant--Digitool to the rescue
Content-Type: text/plain; charset="iso-8859-1"
OK. I've searched my records and don't have time to use the archives right
now. Who do I order the digitool from?
Karl Wolz
----- Original Message -----
From: Tom L. Neal <jneal@NETCOM.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, June 17, 1999 9:19 AM
Subject: Connector contact intermittant--Digitool to the rescue
> Learning summary: Hotter weather and the associated mechanical
> expansion/contraction and corrosion has been triggering electrical contact
> failures in many list vans in the past several weeks. Coils, AFM,
throttle
> switches, others.
>
> One PREVENTATIVE measure is to clean connector contacts by
> 1)pushing connector on and off or
> 2)clean contact by scraping with something like steel wool
> then mate the connector with a little contact grease like the formula made
> for spark plugs.
>
> The story below shows how the digitool can catch some contact problems
> and can prevent big trip disasters and high cost troubleshooting
> ---------------------------------------------------------------------
>
> Symptoms: Started south from Sacramento on warm June 11 day. Temp 2
> started at 1.1V cold and nicely declined to .21. In heat of San Joaquin
> Valley sometimes reading would jump from .21 to .35 to .5 to .21 then
> after a while stabilize at .21. Between LA and San Diego in stop and go
> traffic, jumped to .95V while stopped. Could barely get the van to move.
> Should have checked O2 right then but didn't. Went back to .21. Slight
> correlation of voltage bouncing around with road roughness, and problem
> seemed more likely when engine or outside temperature was higher.
>
> Research:
> 1)Read the Bentley diagram and Temp 2 location and removal.
> 2)Very helpful list member (that I was trading shocks for hubcaps with)
> pointed out location of Temp 2 since I'd never touched it
> 3)Consulted the oracle of vanagon fuel injection (Darrell Boehler)
> about the problem. Darrell noted that the feedback loop opens with
> Temp 2 above .3 v which is very bad since the engine will run rich.
>
> Most likely (and easiest to fix) theorized failure mode: Connector
contact
> slightly intermittant (higher resistance sometimes which would cause the
> symptoms) due to corrosion, vibration and heat.
>
> Experiments:
> 1)Had son watch reading while jiggling the connector. No change.
> 2)Unplugged Temp 2. Digitool reading 4.5V (!)
> 3)Plugged Temp 2 on and off about 20 times, put some contact grease
> on (thank you Debi), drove 2000 miles to Austin without a flicker of the
> Temp 2 reading.
>
> See PREVENTATIVE measures in the Learnings summary at the beginning.
> Key learnings for me:
> 1)Every couple of years clean and put a tiny amount of dielectric grease
> (to keep corrosion elements like oxygen out) all
> interesting looking electrical contacts. Haven't done that yet since
> am still on a trip and don't want to break something that currently
works.
> 2)DIGITOOL: DON'T LEAVE THE DRIVEWAY WITHOUT IT! It pointed to the
problem
> before the van performance had given any symptoms whatsoever.
> 3)I'm real appreciative for all the help from the list. The combination
of
> about 10 people's inputs, plus knowing far more than I ever wanted about
> connector failure mechanisms at work, really nailed this problem at the
> start and added one more item on my long preventative maintenance list.
>
> Given the vanagon caused chaos that has taken place on some other trips,
> I'm thrilled to have....
>
> Ducked a big one, Tom Neal '87 syncro
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