[V8] no start sometimes

[Ingo Rautenberg]

Oh, Dave!  I like your WAG. And sensor testing methodology. Seems probable
to me.

Ingo

On Mon, Aug 10, 2009 at 10:10 AM, Dave Saad <dsaad at icehouse.net> wrote:

> Yes they can be tested!
>
> If you can get them off the car, all you need is an ohm meter and a
> hot air gun.  By the way, you could probably pull codes to get the
> same info.  The ECU probably knows why it is unhappy, but anyway to
> test, remove the sensors and gently hold one in a vice.  Connect an
> ohm meter to the two signal wires and you should read about 1000 ohms.
> As you heat the sensor tip up with the hot air, you will see a gradual
> rise in resistance, then it will begin a sharp increase, then it will
> open up.  As it cools, it will eventually go back to 1K ohm.  Don't
> get crazy with the hot air either or you may just accelerate the
> already common fail mode for this sensor.  My bet is that you have 4
> intermittent sensors.  Audi/VW seem particularly clueless in the
> design of this part as it is a problem on other newer motors as well.
>
> I agree with a previous post (Steve?) that using starting fluid should
> not fix an open sensor, but how about this WAG: maybe the starting
> fluid ignites from compression - like a diesel, and the increase in
> RPM allows the ECU to use the cam position sensor for timing reference?
> Then the motor could magically begin to run.
>
> I should probably drink more coffee before tossing WAGs around - but
> it is kinda fun.
>
> Dave
>
> btw, WAG = wild assed guess.
>
>