Date: Fri, 22 Aug 2003 17:57:56 -0700
Reply-To: Tom Young <tomyoung1@COMCAST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Young <tomyoung1@COMCAST.NET>
Subject: Re: start - won't sart - solution
Content-Type: text/plain; charset="iso-8859-1"
From: "Eric McRae" <dadofanna@COMCAST.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, August 22, 2003 4:45 PM
Subject: Re: start - won't sart - solution
> I'm a new listmember and I have an '89 Wolfsburg that won't start before
> I replace the ECU I wanted to eliminate everything else. This thread
> caught my attention and I have a few questions. First which temp sensor
> did you replace? So far I have eliminated the plugs, wires,
> distributer, and coil in the ignition system as possible causes.
> Fuel/air mixture is making it into the cylinders but there is no spark
> to ignite it. Please tell me an inexpensive temp sensor could be at
> fault instead of the $$$ ECU.Sorry if this has already been answered and
> I missed it.
Eric:
As you can see from my sig below, I know *nothing* about water-cooled
Vanagons, so...........
First, as far as the air-cooled Vanagons go, the ECU has *nothing to do*
with ignition. It controls only the FI system. You could take the ECU from
an air-cooled Vanagon, throw it in the bushes, and the engine would "spark"
just fine. Now, maybe it's different on the water-cooled beasts, but the
ECU would be about the *very last* thing I'd ever replace on a Vanagon
engine. Generally, the ECU's in the Vanagons are very robust and very
rarely go bad. If the ECU has a role to play in the ignition some of my
water-cooled brethren will chime in here.
Second, and again limiting myself to air-cooled Vanagons, a temperature
sensor gives information to the ECU which enriches or leans out the basic
fuel/air mixture in response to the ambient air temperature (the "Temp1
sensor" in the AFM on an air-cooled Vanagon) and the temperature of the
engine (the "Temp2 sensor" on an air-cooled Vanagon). It has *nothing* to
do with "spark" and I can't think of any way this would change with a
water-cooled engine.
Third, (and I'm assuming the ECU doesn't play a role in the game here), when
you don't have "spark" you work logically backwards: if no spark at plugs,
then check for no spark at wire to distributor, then check for power to the
coil, and so forth. Modern ignition systems have made the logical
"backward" check a little more difficult than it used to be in the days of
points and condensers, but the methodology is the same.
No spark could be as simple as a loose wire or a faulty ignition switch.
Have you worked backwards to see where the fault lies?
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Tom Young '81 Vanagon
Lafayette, CA 94549 '82 Westfalia
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