Date: Thu, 31 Jul 2008 18:12:01 -0700
Reply-To: Evan Mac Donald <vanagon_dad@SBCGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Evan Mac Donald <vanagon_dad@SBCGLOBAL.NET>
Subject: Re: ECU and lean idle
In-Reply-To: <48924AC8.4050801@gmail.com>
Content-Type: text/plain; charset=iso-8859-1
Have you looked at the contact surfaces on the ECU, where the wiring harness connects? If there is any corrosion / crud on the contacts, that may cause this. I also had a heck of a time once with mine, when I found the contacts were bent up, and were only making intermittent contact at the ECU. Drove me crazy, because it was on-again-off-again. I had never had the ECU off, so I never suspected the contacts were messed up. Your "magic" ECU may have cleaner contacts, or it may just have the contacts in a slightly different aliggnment, and so makes better contact.
Mike Elliott <camping.elliott@GMAIL.COM> wrote: Yesterday I posted about the problem I have with my 84: after it's warm
(barely), it doesn't idle well, it starts to act like it's missing, the
rpms spiral downward, and it dies. It also has this huge flat spot when
accelerating from a stop. Usually. Not always.
This is something I'd like to have tidied up before I head out of here
and begin our move to Bend, Oregon, on August 10.
So my local shop stuck a sniffer on it and found that when it gets weird
like that, the mixture is way lean. They tried this and that, including
another O2 sensor, jiggered with the air flow meter, then eventually
popped in their test ECU and the problem went away, the van drove great.
Put mine back in, and the problem returned.
So okay, the problem is the ECU, right?
Not necessarily.
I have two other pieces of information that suggest otherwise. First, a
loaner ECU from a nearby Vanagon guy didn't fix the problem (although I
was really paying more attention to fuel economy at that time, so maybe
it helped? Don't recall). Second, the O2 gauge on the dash doesn't show
any lean condition.
So maybe the loaner ECU was also whack in the same way, and maybe the
dash O2 meter is not seeing what their sniffer saw for some reason?
That's two out of three ECUs that show the problem. A small sample with
a 66% failure rate.
I can't deny the fact that the engine was much happier with their ECU.
So here's my plan:
1. I asked the shop to tune the engine to work well with their ECU, had
them put mine back in, and drove it home this afternoon. Boy it runs
like doo-doo right now, but the shop owner is willing to pop his back in
and show me what a peppy little puppy the van is with everything working
so I think I'm ready for:
2. In a couple days, I'll be receiving a couple more loaner ECUs from
fellows here on the list (thanx, guys!) and also hope to visit the
automobile graveyard in Otay Mesa (near San Diego: wrecking yards
covering hundreds of acres, cars packed behind chain link fences --
that's a Superfund site in the making!) and if I'm lucky I can pull a
couple more ECUs.
So unless my service shop has a magic ECU, I'll find one that works
swell. But even if I don't find a good one, (and here's the cool thing)
the shop owner is willing to let me borrow his ECU for my drive to Bend
and ship it back when I get there. Nice guy.
Once there, I can try a few more ECUs, and if that don't work, then
maybe even buy a rebuild. Looks like Bus Depot has the best price, at
$300 vs $405 (Bus Boys) and $430 (GoWesty).
BTW, they put the van on the lift and poked around and didn't find
anything that might cause worry on a 1,000 mile drive towing a little
utility trailer. Other than the fact that I'll be doing that in 24
year-old vehicle.
--
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
