Date: Wed, 30 Apr 2008 21:57:44 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: 87 Wolfsburg persistent hesitation problem (confusing)
In-Reply-To: <989ea5a20804301809v1f0d51f8h5a9a29841fc573ed@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
The crazy tach is a symptom of a bad pick up (hall sensor) in the
distributor. It could also be caused by bad distributor bushings and/or a
wiring problem.
If so, the sensor if giving extra and incorrect spark information. Each
extra pulse is also a false signal to fire the injectors so you have bad
spark timing, extra sparks, and extra fuel.
A real mess. Get another distributor for testing or replace the pick up
sensor within yours.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
TJ Hemrick
Sent: Wednesday, April 30, 2008 9:09 PM
To: vanagon@GERRY.VANAGON.COM
Subject: 87 Wolfsburg persistant hesistation problem (confusing)
All,
I've been having on/off problems with my 87 Vanagon for several months
now
and need some (more) help. It's on/off as I get disgusted with not being
able to figure out what's wrong and just park the old "box" for weeks at a
time and curse at it loudly. It was running fine for many months and
especially so since it had not had any real tune-up to speak of. I
collected all the replacement parts since the water pump was going I
decided
to give it the full makeover. I did the radiator, the pump, filters (oil,
air, ps, & fuel), plugs, rotor, cap, wires, and replaced some vacuum hose.
Now, it runs like $h1t and has for many months since that day.
So, I figured, I must have dislodged or bumped something since I was in
the area. I have this terrible off idle hesitation and then stalls. It
runs fine as long as your above 2500-3000 rpm. I ended up manually
shifting
the automatic trying to keep that rev's up just to keep it running.
Now, after checking all I could, I got desperate, I swapped the AFM (no
change), I swapped the ECM (no change), I swapped temp sensors 1&2 (no
change), I swapped distributor caps, (no change), I swapped spark plug
wires
and yet NO CHANGE.
The one thing that really mystified me was the tachometer. It would
swing
wildly up to 3500 and stay there or bounce around even at idle. I would
be
driving and the needle would move up to 3000 and just bounce around while
I
was driving. It's weird, the van runs fine when cold but the tach is
occasionally crazy. Once it warms up, the tach is fine and it runs
horribly. I check the grounds all over the engine bay, the wires on the
distributor, I jiggled every wire I could find while running (again, no
change).
One thing has been constant- It's running rich, really rich. You can
smell the fuel and see it running puffs of black (not the oil black but
the
poor combustion burn dark grey-black) smoke. So I'm racking my brain the
other day, trying to figure out what it controlling the rich fuel mixture
and it hits me like a freight train, the O2 sensor. I'm certain it should
run (but somewhat crappy) with the thing out of the loop but I say, "Wait,
check the net, ask the group, then get the tools". So I test it-It
runs the same disconnected or connected but it's probably bad and never
changed since new. Not much help there. Oh, I have to cut it out to
replace it. It's either welded in there by the PO or it's seized. I used
a
LOT of tools on it and it is NOT moving.
So, the floor is open. I've gotten suggestion before and they were damn
good ones at that but yet, my van's engine still runs like a POS. It's
very
discouraging. I work on my own rides, I work on other peoples rides (for
money), I have other vans (same year, same engine) to pull parts from and
I'm still getting my @$$ handed to me by a 20+ year old brick.
Fuming in Florida,
TJ
|