Date: Thu, 11 Sep 2008 12:47:49 -0700
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: Question about temp II sensor and bad running
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probably no harm done, but I sure would not jumper the temp sensor wires .
the ECU expects to see a resistance value there.
if you suspect the sensor itself, and wanted to use a substitute appropriate
value as a test, that's a fine idea,
and get a 2,000 ohm resistor or whatever ohm value the chart in Bentley says
is mid-range.
or for cold temp, that would be fine too, for testing purposes.
the contact at that sensor too............I have messed with 1.9 waterboxer
engines for a long time, only to eventually find the problem was poor or
intermittent contact there, although it's a much better connector on the
2.1.
and you're sure it was the ECU temps sensor you played with, and not the
gauge temp sender ?
I can easily imagine an electronic component, or a soldered connection
working fine, then going off once even a little warm.
If you were local, I'd say come over and get another ecu to try.
There is nothing like having several good test units on hand, for each part.
IF I was concerned about the temp sensor connection and
values..............the more definitive way to test it is undo the connector
at the ecu, and measure resistance all the way from the ecu connector,
through both wires, to the sensor.
Nothing has to be powered up to do this reading.
but that way you are continuity testing the whole length of wires through
the ecu wiring harness, the connection to the temp sensor, and the sensor
itself. And if you get a correct reading, you could also wiggle wires while
watching the ohm meter, looking for a open or poor connection.
it's also a much faster and easier test to pop in an approximate value
resistor. That could get you useful info very quickly and easily.
i.e.. if it still 'does it' when you substitute a proper value resistor,
it's likely not the temp sensor circuit and input to the ecu.
I diagnosed a clogged cat or muffler once by removing the oxygen sensor
..............that made it run perfectly, as having that hole in the exhaust
relieved the pressure from the clogged muffler. Look for simple easy tests
like that that match the symptom.
there's this 'cost/likely benefit' ratio scale - there are some tests that
you don't think are really very likely to reveal anything, but they are so
quick and easy to do ...........that they should be done anyway. Trying it
with the oxygen sensor disconnected is one .........only takes a
second...........
and if things don't change..................that means it's likely not
related to the 02.......but if they do change ..........it probably is.
My point is............( I like that one guy said check the cheap stuff
first ) ..................do the easy tests first.
I think our focus is on the ecu/distributor and ignition stuff.
now if you can catch it when it acts up and see what is missing then
..........that would sure help.
well, get her studying the Bentley !
She's got a brain too, right ? and she's the one that needs it working. she
could/should be in on this.
and........I'm serious...........
when I just don't know what else on earth to do .........I'll ask a non-tech
person for ideas, or a child........
you never know what they might come up with, that will move your mind in the
right direction.
Scott
www.turbovans.com
----- Original Message -----
From: "Jim Felder" <jim.felder@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, September 11, 2008 10:18 AM
Subject: Question about temp II sensor and bad running
> I'm starting a new thread on this because I am desperate to get the
> van running... wife doesn't have a car without it right now.
>
> In the earlier threads I started on this subject, I had the car
> stranded at walmart. Removed the distributor for examination and when
> I went back this morning, it started right up... meaning that
> something in the car cooled down and the start was a coincidence or
> else fiddling with the distributor connection solved the no-start
> problem.
>
> Then another problem appeared or else there was a related problem I
> don't get. The car ran great for less than a minute and then started
> running horribly. I barely made it home two miles away with a spot or
> two of running great, but mostly horribly.
>
> I have started it many times through the morning and afternoon. Same
> thing always happens: starts great, runs strong, 30 seconds or a
> minute later it's stumbling and then it stalls. I can do this until
> the engine gets warm or let it cool and try it, the same thing
> happens.
>
> I removed the wires to the temp II sensor and jumpered the sensor
> connections. No change. I removed the jumper. No change.
>
> Ken Lewis has written and says it may yet be the hall effect sensor or
> the ECU, but I don't understand how a bad connection or failed sensor
> could create such a predictable situation of starting and then running
> more and more poorly until a stall. Maybe it could, but I don't get
> how.
>
> Any ideas?
>
> Thanks for hanging in there with me,
>
> Jim
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