Date: Mon, 4 Aug 2008 10:12:35 -0700
Reply-To: Mike Elliott <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike Elliott <camping.elliott@GMAIL.COM>
Subject: What a difference an ECU made
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...seventy-two little hours.
Those who have been following my quest to fix the poor idle and flat
spot when accelerating that have been plaguing my 84 1.9L will know that
the shop tried this and that to fix the problem, then plugged in their
one good working ECU and the problems vanished. With my ECU they found
the engine went very lean when the engine was circling the drain.
So working on the theory that the ECU was the problem, I asked them to
tune the engine with their working ECU, and pop in my suspect ECU so I
could limp home then find a good one.
(As an aside, I see that they removed the blanking plate as shown on
Bentley 24.30 to access the CO adjustment screw on the AFM, I reckon
they did that during the process.)
One ECU was kindly loaned to me by Bryan Feddish, it arrived on Saturday
but things intervened so I could not install it. A second one turned up
in a 84 that had been newly-delivered to an Ecology wrecking yard near
San Diego.
With the old ECU, after the engine had been on for about a minute, it
started to slow and hiccup a bit, the mixture went a little lean, the
engine started to miss more, the mixture went leaner, and the engine
eventually died. The O2 monitor showed little activity during this process.
This morning the suspect ECU was swapped out with the wrecking yard one,
the engine started strongly, and after about a minute, the engine
started to slow, with a hiccup or two, then the mixture went richer, and
the engine returned to a strong, smooth idle.
Took the van for a drive and it was strong, it didn't want to die when
idling at a light, and it showed no sign of any flat spot. While
driving, the O2 readout was peppier. As a test I installed Bryan's
loaner, with the same excellent results. Then I put in the old one, and
the funky behavior returned. It wanted to die, and the flat spot was so
severe that the van didn't even want to pull out of the driveway.
The problem she seems to have been fixed! Thanks all for supplying
additional troubleshooting ideas.
Bryan: request permission to haul your ECU along with me on the drive to
Bend as a backup?
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR