Date: Thu, 10 Apr 2003 14:14:39 -0400
Reply-To: Laurence Smith <laurence@ALANASMITH.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Laurence Smith <laurence@ALANASMITH.COM>
Subject: Re: Vanagon Syndrome
In-Reply-To: <5.1.1.6.0.20030410062207.00a89660@mail.gct21.net>
Content-Type: text/plain; charset="US-ASCII"
Right on Steve! Grounds, grounds, grounds!
I learned this the hard way. On my first Vanagon I had very rich
running problems. I changed out many Digifant components only to find
cleaning of a simple ground wire fixed the problem.
When I bought my second Vanagon I was a "grounds" convert. The guy
selling me the van complained about rough running. Not much of a
salesman, but it was obviously rough. Got it for $1500. I
immediately fixed all the grounds (for $zero) and it ran like a champ.
- Laurence
> -----Original Message-----
> From: Vanagon Mailing List
> [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
> Of Steve Delanty
> Sent: Thursday, April 10, 2003 10:34 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Vanagon Syndrome
>
>
> >I have lived in denial for three years. This is what
> happens, after about
> >1 - 2 hours of driving, the darn thing would just quit on
> me (like its out
> >of gas or lost its spark).
>
> Uh huh...
>
> >After replacing all these parts and still fighting with the darling
> >beastie, I discovered this list and have spent a couple of
> hours reading
> >the "Vanagon Syndrome" archives and found two promising
> fixes; a new
> >wiring harness for the air sensor and a capacitor installation.
>
> I have the fancy wiring harness. I also added the AFM
> capacitor. In my case it
> didn't help.
>
> >Can anyone tell me what size capacitor and where and how
> to install it? I
> >assume I can get the wiring harness from a parts store or dealer.
>
> Here's the scoop on the capacitor:
> http://www.geocities.com/harald_nancy/intermitt._syndrome.htm
>
> The capacitor allegedly does the same thing as the harness.
> The capacitor will cost under $2. The harness will most assuredly
> cost more. Try the capacitor first. Neither helped me.
> -----------
>
> I'm certainly not a digifant expert, and I've only owned a vanagon
> a couple months, but I'm not a stranger to electrical
> troubleshooting
> and based on a bunch of hours with a scope and VOM peering into
> the engine hole, and from what I've read on the web, here's MY
> OPINION about vanagon syndrome.... FWIW
>
> I think that "vanagon syndrome" can be caused by a wide range
> of things, all of which confuse the AFM until it blows it's mind.
> A quick key-off reset clears it's mind and all is well...
> until next time.
>
> It's also my opinion, from all I've read on the web, and from my
> own testing that a large percentage of the time this is caused
> by flaky electrical connections and especially by insufficient
> grounding. Many folks have apparently fixed their problem by
> finding and repairing a missing/broken/loose/corroded ground
> connection. The 2 flat ground braids, one on the left side head
> and one on the nose of the tranny are the 2 major ground points
> between the engine and body and MUST be clean, tight, and in
> good condition.
>
> Check these items FIRST, before you spend money and time
> replacing parts !!!
>
> In *most* cases, random replacing of parts; O2 sensor, AFM,
> fuel filter, etc. doesn't seem to help except to lighten the wallet.
>
> Unfortunately, the stock grounding mat be barely adequate at best.
> I did some careful measuring with an oscilloscope and found an
> amazing amount of voltage measured between the engine block
> and the body. When the alternator is charging at moderate current,
> there was over 1/4 volt of DC voltage between engine and body and
> another 1/4+ volt of 3-phase alternator noise riding on top
> of the DC
> voltage.
>
> Since the O2 sensor output voltage is only around 1/2 volt, it's not
> hard to see how a 1/2 a volt of DC offset and AC noise on the engine
> ground would screw the ECU bigtime...
>
> The fact that these noise voltages increase with increased
> alternator
> output explains why some folks find that vanagon syndrome gets
> worse when lights, cooling fans, AC, etc are on.
>
> So. After my findings with the oscilloscope on the engine ground I
> did 2 things. First, I added a noise supression capacitor on the
> back of the alternator. This capacitor is stock equipment, but they
> have a tendency to disappear with time, as people forget to put
> them back on during an alternator replacement. Mine was missing.
>
> I don't know the value for the stock capacitor, but I used 0.5 uF
> 250 volt ceramic disc capacitor on mine. Or you can goto the
> FLAPS and buy one for almost any make and model of car
> and it should work fine. Even the condenser from a points type
> distributor will work good. These are typically 0.25 - 0.5 uF at
> a couple hundred volts.
>
> The capacitor connects from the + output stud on the back of
> the alternator to one of the ground studs on the alt.
>
> Whatever else you do, if your alternator is missing this capacitor
> GET ONE! I was rather surprised at how much it reduced the
> electrical noise resident on both the engine ground and on the +12
> volt line. It's the first line of defense for providing a
> clean noise free
> environment for the ECU. I think it is VERY important.
>
> The second thing I did was to add a #2AWG wire directly from
> the back of the alternator to the body at the front of the engine
> compartment, well away from the stock ground points on the
> left side. This gives the alternator charging current a nice direct
> path to the body of the vehicle and reduces the current thru the
> stock ground braids, which helps reduce the DC voltage drop
> problem I was seeing across the stock flat braid.
>
> These 2 "fixes" reduced the electrical noise by a factor of about
> 10:1 and has made my wasserboxer run noticeably smoother,
> and I believe it has also cured my vanagon syndrome.
>
> Since the price of 2 feet of #2 wire and some fat crimp lugs for
> the ends is only a few bucks, and the alternator capacitor is
> probably a few bucks from the FLAPS or less from a wrecking
> yard, I think it's probably a worthwhile shot for most syndrome
> sufferers to try. What else can you do to a vanagon for under $20 ?
>
> Sorry for the length of this, but I'm hoping it might help some VS
> sufferers out there.
>
> Please keep me informed of any results, good or bad from
> trying these 2 things.
>
> Happy motoring,
> Steve
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