

| Subject: | Re: Vanagon Syndrome |
| From: | Shawn Wright |
| Date: | Sat, 12 Apr 2003 10:18:27 -0700 |
On 10 Apr 2003 at 7:34, Steve Delanty wrote: > 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. Steve, I did the capacitor fix and extra ground from the AFM a few years ago, and it seemed to make no difference also. <snip> > 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. My alternator appears to have only one ground stud, right beside the larger + stud. Is this normal? I don't have a capacitor, so I will search my electrical junk for a suitable one. > 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. I assume you're suggesting using the ground stud again here? Mine seems rather small, so I'm not sure a #2 wire connector will fit. It appears around an M6 size stud. Any ideas on a good place for grounding to the body on the right side? I'd rather not drill if I can avoid it. I was thinking there must be a bolt on the frame somewhere I could use. I could not see anything obvious when I looked today, at least not within the engine compartment. Shawn Wright, I.T. Manager Shawnigan Lake School swright@SLS.bc.ca http://Zuiko.sls.bc.ca/swright http://www.sls.bc.ca
Have something to add on this topic today? Revive this thread in the forum »