[T3] Head Sensor...

[J. Jonik]

Just tightened the head sensor 13 mm nut.   But, the head sensor wire connection above is one of the routine connections I tidy up, just in case, when engine is funny. Doesn't always work.   But how to know which connection of many did the trick to make car run better?  I rarely would do One at a Time.  

Previous symptoms included some trouble starting, not great acceleration, a bit of roughness at gear change, etc....BUT, often, suddenly, the car would suddenly Cure Itself, for no apparent reason, and run like a champ...til the next day.
  Now that the sensor nut is tightened just a little (making cleaner connection?), it's fine every day....for now.
   No bent sensor wire....but I adapted a socket wrench small extension to allow the wire to pass unharmed through the 13mm socket so I can tighten/remove that sensor nut. (Just ground a metal notch on one side of the male part of the short extension.)  Easier than trying to jam a 13mm wrench somehow under the engine tin or whatnot to get to it.

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On 9 Sep 2018 at 4:13, J. Jonik wrote:

>  I thought to just tidy up and re-tighten the Head Sensor. Bingo. <

(J.A.)  I gather that you did this again and now your engine is running. Is that 
correct?

What did you tighten, the threaded part into the head, or the 1/4" spade 
connection at the end of the wire?

One problem that happens with those sensors is that the wire gets bent 
sharply where it exits the sensor. At some point, the insulation breaks and 
the wire shorts out to the sensor body, making the sensor resistance zero. 
That will bring the engine to an instant halt. This was a big problem 
especially with the 68-9 engines, where the sensor was installed below the 
#4 exhaust port and had no choice but for the wire to bend sharply where it 
exited. I always recommend that those early engines be converted to the late 
head sensor location, which means installing a different left head.

Even for the late engines, '70-on, I recommend being careful of that wire and 
making sure that it comes straight out of the sensor and never gets bent 
there.