Date:         Thu, 20 May 1999 13:12:48 -0500
Reply-To:     "John Y. Hung" <jhung@ENG.AUBURN.EDU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "John Y. Hung" <jhung@ENG.AUBURN.EDU>
Subject:      interesting problem ... solved
Content-Type: text/plain; charset="us-ascii"

Dear Fellow Listers,

Had an interesting problem with our '84 Vanagon GL (145,000 miles on
original engine).  Occasionally (cool weather), the engine would not
restart after shutting down less than 15 minutes.  If one waited longer
(engine cooled down), the engine would start.  Starter cranked just fine.
The problem became worse with warmer weather.  Checked ignition wires and
computer connections per Bently manual instructions.  Replaced spark plugs
and distributor cap, and problem went away for a few days.  Wife was
stranded last month (not a happy camper!), and we ended having to push
start the van (manual transmission).  The engine also missed at highway
speeds, even slowing down, then would rev back up as if nothing happened -
really weird.  I couldn't find anything wrong when we got home.  Of course,
my wife is distrustful.  Last week (warm weather), the van got stranded
again - my wife declared it was time to buy a Chevy Suburban (gasp!).  No
amount of waiting helped, and the push start was needed to get home.  I
waited a few days, and the engine still would not start.  By this time, the
battery was weakened from hard cranking, and the engine barely turned over.
So, I push started again, and the engine fired right up!  Shut off the
engine after recharging the battery ... it would not restart.  Push start
worked right away.

Solution:  Replaced all ignition wires (get them from Bus Depot - about $65
w/ shipping).  The old set was the original set.

My hypothesis:  The electrical tests recommended by Bentley are static,
"DC" tests.  When the engine is running, the dynamic electrical properties
are much different, so marginal wires may not show up in the DC tests.  In
cooler weather, or with a cold engine, the computer slightly enriches the
mixture to help starting.  With warm engine, no enrichment occurs and the
marginal ignition system prevented the engine from running.  I attribute
the intermittent engine missing to the old wires as well.  Why does push
starting work, but not cranking?  Apparently the starting load draws the
electrical system down sufficiently to further weaken a marginal ignition
system.  Changing the spark plugs and distributor cap earlier probably
"cleaned up" some old connections, but that wasn't sufficient long term.

We've been running almost a week now with no problems.  Wife is not talking
about Chevy Suburbans as often.  I'll let you know if the problem
re-surfaces.

John Hung
Auburn, AL
'86 GL