Date: Thu, 10 Oct 2013 20:08:10 -0500
Reply-To: Jim Felder <jim.felder@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jim Felder <jim.felder@GMAIL.COM>
Subject: Re: Runaway Engine RPMs
In-Reply-To: <CAHTkEuLmbfm5u3E9roh-CFGjtG+sy5SfW3oF6TOQRCj6qhUyig@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
10-4 to that.
Although after following this list for eleven or so years, I have
discovered more about 12 v electronics than in the previous 50+. And my dad
was an electrical engineer and a damn good one... not much rubbed off on me.
Jim
On Thu, Oct 10, 2013 at 8:02 PM, Don Hanson <dhanson928@gmail.com> wrote:
> I always check the mechanical stuff first...because I am not comfortable
> with Ohms, watts and that stuff...Eventually I can get through the
> electrical parts, but geeze! it seems like every time I pick up my
> multimeter or try to read it and follow a Bently or other factory
> electrical trouble shooting guide, about half of my readings are not even
> found in the same units I am looking for or the fuse is blown or a wire is
> loose...Tedious is what I find messing with resistors and relays. Give me
> a torque wrench or a die grinder and I am ok to go...give me 2-1-2 blinks
> of my Check engine diagnostics and I get frustrated pretty quickly...
>
>
> On Thu, Oct 10, 2013 at 5:56 PM, Don Hanson <dhanson928@gmail.com> wrote:
>
> > I think it sounds like something in the throttle body or the
> > linkage...Perhap the TB is getting worn and allowing the throttle plate
> (is
> > that what you call it?) to stick or get pulled open due to wear and or
> > loose something... might be worth looking at the condition of the
> > mechanical part of your intake...
> >
> >
> > On Thu, Oct 10, 2013 at 4:28 PM, Larry Alofs <lalofs@gmail.com> wrote:
> >
> >> John,
> >> If you have access to an ECU to swap in, it might be worth a try. I
> was
> >> struggling with a '91 about a year ago. It had various running/idling
> >> problems that I gradually solved; during which I put in an ECU that I
> had
> >> once tested and found to be OK. Suddenly the van refused to idle down
> >> properly and nothing I did could fix it until I put the original ECU
> back
> >> in. The idle was not 3K, more like 2300, but way too high. I repeated
> >> the
> >> swap to be sure and retired that ECU. I looked at the circuit board,
> but
> >> could not see anything suspicious.
> >>
> >> Larry A.
> >>
> >>
> >>
> >> On Thu, Oct 10, 2013 at 4:54 PM, John Meeks <vanagon@gmail.com> wrote:
> >>
> >> > Thanks Scott -
> >> >
> >> > I'll try unplugging the ISV next time it does this. I think that's a
> >> good
> >> > troubleshooting first step. Not sure yet what it will tell me. I think
> >> that
> >> > valve just add more more less air to the mix. You can hear the little
> >> motor
> >> > running in there with the key on.
> >> >
> >> > It's probably worth inspecting the ECU solder joints with a strong
> >> > magnifying glass too. I'll be able to do that this weekend.
> >> >
> >> > John
> >> >
> >> >
> >> >
> >> > On Thu, Oct 10, 2013 at 3:28 PM, Scott Daniel <
> >> scottdaniel@turbovans.com
> >> > >wrote:
> >> >
> >> > > I sure wouldn't call 3K rpm 'runnaway' ..though it does sound
> really
> >> > > dramtic to discribe it that way.
> >> > > if it was really runnaway ..
> >> > > it would be screaming at 6,000 rpm or so.
> >> > >
> >> > > I wouldn't think that the TPS telling the ecu that your at full
> >> throttle
> >> > > would do this.
> >> > > I believe all that does is bypass 02 input at WOT.
> >> > >
> >> > > And ..I have seen the electronic control unit and/or idle air valve
> >> cause
> >> > > this.
> >> > > I've had a vanagon sitting in a bay of my shop idling ..
> >> > > suddenly jump to very high rpm all by itself.
> >> > >
> >> > > Unplug the Idle Air Valve right there on top of the engine.
> >> > > ISV valve sometimes called too. Idle Stabilizer Valve.
> >> > >
> >> > > Scott
> >> > >
> >> > >
> >> > >
> >> > > On 10/10/2013 9:44 AM, John Meeks wrote:
> >> > >
> >> > > Yesterday I was in a 2 mile stop and go traffic jam. About 3/4 of
> the
> >> way
> >> > > the low speed fan came on as expected. A minute later the engine
> >> revved
> >> > up
> >> > > tp 3K rpm and stayed there. The gas pedal was all the way up.
> Couldn't
> >> > get
> >> > > off the road so I turned off the engine when there was a stop
> >> situation.
> >> > > Turning it back on the engine revved right up to 3K again.
> >> > >
> >> > > Finally pulled into a parking lot and waited about 15 minutes.
> Started
> >> > > normally with no recurrence the rest of the way home.
> >> > >
> >> > > I had this same problem about a year ago (intermittant) and 'fixed'
> it
> >> > with
> >> > > a new throttle cable and cleaning out the rust and dirt from the
> >> pedal to
> >> > > cable housing. Now it's back!
> >> > >
> >> > > Side note just put the engine in after head gaskets and ring
> >> replacment
> >> > > and It was running great for the past week.
> >> > >
> >> > > Could the TPS be the culprit if it made the ECU see full throttle
> and
> >> ECU
> >> > > then enriched the mixture?
> >> > >
> >> > > Any ideas are welcome.
> >> > >
> >> > > John Meeks
> >> > > '91 Vanagon MV Phoenix
> >> > > Stock 2.1 250K miles
> >> > > Northern Michigan
> >> > >
> >> > > Vanagon Rescue Squad <
> >> > http://www.vanagonauts.com/Vanagon-Rescue-Squad74.htm> <
> >> > http://www.vanagonauts.com/Vanagon-Rescue-Squad74.htm>
> >> > >
> >> > > Android and iOS apps
> >> > > www.vanagonauts.com
> >> > >
> >> > >
> >> > >
> >> >
> >>
> >
> >
>
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