Date: Fri, 14 Nov 2008 19:30:08 -0800
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: strange idling behavior ? (long post with plenty of
diagnostic hints)
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Did you do a careful visual inspection of the engine, and ALL hoses and
fittings in the air intake system ??
if it uses an auxiliary regulator fast idle system...........I'd be looking
at that device and the hoses to it.
Intake manifold leaks come to mind.
Or a vacuum hose off.
if it has electronic idle control, like a 2.1 waterboxer engine.........the
Idle Control Valve with a 3 wire connector in it.........
I'd be thinking about that part and system too.
I'll tell you ..................I only occasisionally find that it's one
'faulty part' ............as in one failed part that's causing 'the issue'
............I only find that that's what it is a very small percentage of
the time.
The majority of the time..............it's about connections, and leaks.
In hoses, in electrical connectors etc.
Or............I find about 7 'half tired' things. or 10.
It must be that I mainly see the abused and neglected vanagons, since I buy
them sometimes dead - but............I swear, on most vanagons engines I
see.............I find 10 things wrong on them.............whether loose, or
missing, or the wrong or cheap part..............or just old and warn out.
It's seldom that an engine is in perfect tune and well sorted
out.............then 'one thing' fails completely, while the other 50 things
involved are all still perfect.
It's a 'collection' of things that have gotten out of spec, or just tired in
general.
'air leak' ...........air leak fits your symptom, and I'd go looking for
those to start with.
Let us know what you find Don !
Scott
----- Original Message -----
From: "Don Hanson" <dhanson@GORGE.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, November 14, 2008 6:17 PM
Subject: strange idling behavior ? (long post with plenty of diagnostic
hints)
> 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..
>
> Don Hanson
>
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