I have had the 3/4-power problem hit my van several times.  Latest was a few
weeks ago and everything concerned (including the block) was new last
summer.  I found that the #3 plug wire was the culprit.  Connector to the
spark plug was heavily corroded.  Wire set this time was Beru, but I have
also had it happen with Bosch wires.  Replaced the bad wire and problem went
away immediately.

John Lauterbach
Macon, GA
'84 7-passenger

----- Original Message -----
From: "Shiva Polefka" <shiva@EDCNET.ORG>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, August 24, 2004 2:14 PM
Subject: '84 1.9: 3/4 power and running ugly

> Hello again-- many thanks to those that replied to my previous post.  I
> realize I should consider searching the archives more extensively, but I'm
> already $300 and many hours in to this problem without any improvements
and
> would like to be tossed a bone.  In advance please pardon the lengthy
> narrative and request for help that follow.
>
> My 1984 GL has been maintained attentively and pre-emptively during its
> entire 120k.  Last month, as i ascended Wyoming's Big Horn Mountains (up
to
> 10000ft) , the engine switched from a smooth running hum to a rougher but
> regular throaty purr.  The next day, back at 3000ft, the van continued to
> make this more ugly sound, and felt like it was running on 3/4 power --> i
> couldnt drive faster than 55mph, and it took a long time to get up to that
> speed.
>
> Wyoming's local garage monkeys claimed they could fix vanagons.  They
> replaced the fuel filter, the spark plugs and the distributor rotor, and
> claimed the problem was fixed.  As soon as i hit the road again however, i
> discovered that in fact the problem appeared to have not even been
addressed,
> with all symptoms essentially unchanged.  Needing to return to the job
> however (rather than wait any more in WY), i crossed my fingers and
> continued, and wound up limping slowly but succesfully all the way back
> across the Western states to Southern California.
>
> That experience allowed me to log with some exactitude the symptoms of my
> van's malaise, which follow: in the morning, when starting cold, the
engine
> runs somewhat smooth and fully powered, but displays the infamous chugging
to
> a significant degree.  After ~5minutes of running (after the thermostat
opens
> up?) power drops off dramatically, and the engine switches from smooth hum
to
> throaty purr.  In fourth gear, at ~50mph, the "miss-y" (but regular)
> throatyness and diminished power are particulary acute, and getting above
> this speed is really difficult.  A long hill here in town that used to be
> ascended in 3rd gear at 35 is now a humiliating second gear, ~20mph
> experience.
>
> Once this apparently temperature-induced transition occurs,
lurching/chugging
> ceases.  A couple times while at highway speed, i've felt a temporary
surge
> as throatiness disappears and full power resumes.  each time this lasted a
> couple seconds, no more.
>
> My local mechanic, who is widely considered trustworthy and experienced,
was
> unable to figure it out.  He changed the sparkplug wires and added German
> fuel-injector cleaner, to no effect.  If memory serves, his compression
test
> yieled 165 on two cylinders and 135 on the others.
>
> My internet searching has lead me to suspect my air flow meter, dirty
> grounding wire attachments, a need for a $190 "wiring harness," or a
vacuum
> leak issue.  Any clues as to where to look next would be -greatly-
> appreciated.  Thanks in advance--  my combination of frustration and love
> evoked by my van makes me really look forward to getting it back up to
full
> speed.
>
> sp.