T3: Re: General SOS :( - a plea for help

[Greg Merritt <gregm@vwtype3.org>]

	(Be careful with the I & II designations--I can quote you, in
print, totally opposite labels for the head & intake temp sensors!  I find
it safer to use the names "head temp sensor" or "intake air temp sensor".)

>Before we had had problems with tempurature sensor II, but we fixed
>that....now it's tempurature sensor I that is giving us the infinity
>reading...

	I recall that you made a repair w/ the head temp sensor.

	Now you're having trouble w/ the intake air temp sensor, right?

	An otherwise well-running car can run with the intake air temp
sensor disconnected.  In fact, one book cites disconnecting this sensor as
a way to make a rough car idle better.  Clearly a kludge--it'll run
rich--but it shouldn't kill the car, I think.


>and when we checked the wiring, it gave us an infinity
>reading too...but the wire that sticks out of the harness is
>complete, which means the break is somewhere inside the harness, and
>I don't know how to tackle that sort of problem.

	Don't mean to be rude, but I thought it would be a good idea to
confirm your testing of the harness.  How did you test the harness?  With a
good harness & a good temp sensor, you could of course take off the big
harness plug at the brain & measure resistance across the correct pair of
leads.  A busted (open circuit/infinite resistance) temp sensor would of
course give an infinite resistance at the big harness plug.  Now, removing
the sensor--good or bad--would give an infinite reading.  To test the
harness, you'd have to check each of the two leads separately.  One end of
your tester would be at the big, huge brain plug end and the other end
would be at the corresponding lead on the sensor connector plug at the
other end of the harness.

	I would suspect that 99.9% (don't quote me;) of damaged harnesses
are damaged right at the connector.  (It sees all of the action; all the
rest of the harness pretty much just sits there.)  I would pull back the
rubber sleeve over the connector to expose the hard plastic plug & the
leads.  If you need to "rebuild" the connector, you can slip the individual
skinny, skinny spade connectors out of the plastic plug by inserting a
stiff wire or pin or something into the hard plastic plug at the business
end--you need to depress a little tab on the back of the spade connector,
and it'll slide right out the back of the plug.

>But we're concerned
>that that's not all of the VW's problems...can tempurature sensor I
>be responsible for the car not starting?

	See above... I don't *think* so, but I've been known to be wrong.
:)  I'm assuming you mean the intake air temp sensor.  If the sensor were
bad & the harness good, you could rig a resistor (Radio Shack!) of
appropriate value in there to tie you over until you replaced the sensor.

>Paul is worried that my car's brain died.....is there any way to test
>the brain?  Is there anyone in Southern California I can seek help
>from?  :(

	It is exceedingly rare to have a failed computer.  Really, really
rare.  Super rare.

	I know of several people who have taken their Type III to a VW
dealer(!) and paid for the 60 or 90 minutes of labor for them to hook it up
to their diagnostic equipment & give a complete report of the injection
system.  Tell them thank-you-very-much, pay your bill, and go find your
parts elsewhere & install them yourself.

	You'll find that this costs much less than a brain--particularly if
you find out the hard way that the brain isn't the problem!

Persevere...

-Greg
'69 & '71 Squarebacks
'63 Beetle