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Subject:Re: strange idling behavior ? (long post with plenty of diagnostic hints)
From:neil N
Date:Fri, 14 Nov 2008 18:43:53 -0800

Don.

I'd check for a vacuum leak first. I don't know Digifant, but vacuum
leak is my first thought.

Also check out the Vortex.com They should have a section dedicated to
your fine 1.8 8V. Not mentioning that it's in a Vanagon may help,
though the guys on the 2.0 list have been most helpful and some were
even interested in my conversion.

Cheers,

Neil.

On Fri, Nov 14, 2008 at 6:17 PM, Don Hanson <dhanson@gorge.net> wrote:
> 84 vanagon with an inline VW 1.8 motor.
>
>  Not really a vanagon question, I guess but many on the list seem pretty
> familiar with the little inline 4 VW motors.  They also have the same or
> similar fuel injection to vanagons, so Helpful hints would certainly be
> appreciated as to where I might look.
>
> This little 1.8liter, 8-valve, from a '92 rabbit cabriolet (Digifant II
> injection) , has always behaved perfectly until just this morning.  Upon
> start up..not super cold or anything, the idle didn't drop like it always
> has after the motor warmed up.  It usually runs at like 1200rpm for a few
> minutes, then drops down to a normal idle..This morning it seemed to be
> idling a little higher than normal, and it didn't fire up and settle right
> into it's pace, but kinda stumbled around a bit, then settled in at it's
> warm up RPM.  (no throttle from the gas pedal, ever)
>
>  No dash warning lights, no abnormal driving preceded the onset of the
> problem, all the gauges read the same as always.  I did run the tank dry a
> few weeks ago and I have noticed my fuel pump is slightly more audible than
> before, but I've had no indications that the fuel pump is having
> problems...yet.  And it does run fine down the road..
>
>  I headed out, with the high idle,  and at my first normal stop sign, the
> idle was still up at around 12-1500rpms.  It normally would have gone to
> it's regular idle (about 7-800rpms, I guess)  mode by that point, but not
> today.  Then, as I came into the next stop-after about 20 miles of highway
> speeds,( totally normal behavior, other than the high idle between shifts)-
> the idle was "hunting"...it was doing about 3-second cycles...Up to
> 1500......down to normal....up......down... up..I blipped the gas pedal
> without any effect to the hunting...It did that for my cross town trip of
> about 3 miles and a couple of stop signs, then I shut it off and went bike
> riding...It cooled down for about 2 hours then.
>  Under throttle, when driving, everything seems to be running properly.  No
> smoke, no missing, no detectable loss of performance.  Weird... I drove
> around town and put about 45 miles on today with no problems other than the
> high/and or/hunting idle..
>  Just now, coming home, the 'hunting' has stopped again, but the idle
> remains much too high...1500+ rpms (guess-ti-mate)  I left the van running
> and went round to check the exhaust...smells normal..not super-rich or in
> any way stinky.
>
>  So, any guesses or suggestions?  First thing I'll be looking at will be
> the Temp II sensor, my guess.  That seems to cause all kinds of weirdness in
> the Digifant II system and other VW injected vehicles.  I have never been
> able to find a 'throttle position switch' on this vehicle...but then the
> Bentley I have (for the Cabriolet motor) is not worth squat on that
> particular point..I may not have one, who knows..I wouldn't think that would
> cause the "hunting"...Hope it isn't the EMS Brain...
>
>  Thanks in advance...Hey, it's even Friday so if this isn't list
> appropriate..it's at least posted properly..

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