[xj] '86 SIII Federal water rail question

Yesterday, I fiddled a bit with the car, replacing a vacuum line and
repairing some brittle wires. I ended up using some plain automotive
wire (losing the color coding). While studying my repair manual and
the electrical manual, I couldn’t figure out what these wires were
attached to. The wires in question are:

  1. A pair attached to the negative terminal of the coil. One (White or
    maybe Pink/Black) goes to a bullet connector towards the end of the
    valve cover, and I think it’s probably for the tach? The other
    (Pink/Blue) disappears down below the intake manifold.

  2. There was a solid pink attached to the positive terminal of the coil.

  3. And there was a wire (Green/White) attached to a sensor on the
    water rail immediately aft of the coil. One book seems to suggest it’s
    the water temp sensor. Another shows a larger sensor, one location
    further aft, and states that’s the temp sensor. So what’s the sensor
    my green wire is attached to?

I really loved reaching down under the manifold! Particularly since I
had a valve cover leak up above…

Regards,

Peter Morris
Vista, San Diego County
California
'86 Jaguar XJ6 SIII
'78 Fiat Spider
'93 Ford Escort

Peter: the green wire aft of the coil IS for the temperature gauge sensor.
The other “temperature sensor” further back on the water rail is the coolant
temperature sensor connected to the ECU. This enables the ECU to determine
the correct mixture (pulse duration) during the warm-up period. If this
fails, a typical symptom is stalling during the warm-up period because it
tells the ECU that thengine is warm when it is not! A faulty reading here
can be cause if an air lock is induced at the time of coolant change (don’t
ask how I know).
Gregory----- Original Message -----
From: Peter Morris pmorris@tfb.com
To: xj@jag-lovers.org
Sent: Monday, November 08, 1999 5:35 PM
Subject: [xj] '86 SIII Federal water rail question

Yesterday, I fiddled a bit with the car, replacing a vacuum line and
repairing some brittle wires. I ended up using some plain automotive
wire (losing the color coding). While studying my repair manual and
the electrical manual, I couldn’t figure out what these wires were
attached to. The wires in question are:

  1. A pair attached to the negative terminal of the coil. One (White or
    maybe Pink/Black) goes to a bullet connector towards the end of the
    valve cover, and I think it’s probably for the tach? The other
    (Pink/Blue) disappears down below the intake manifold.

  2. There was a solid pink attached to the positive terminal of the coil.

  3. And there was a wire (Green/White) attached to a sensor on the
    water rail immediately aft of the coil. One book seems to suggest it’s
    the water temp sensor. Another shows a larger sensor, one location
    further aft, and states that’s the temp sensor. So what’s the sensor
    my green wire is attached to?

I really loved reaching down under the manifold! Particularly since I
had a valve cover leak up above…

Regards,

Peter Morris
Vista, San Diego County
California
'86 Jaguar XJ6 SIII
'78 Fiat Spider
'93 Ford Escort

Peter,

Our 79xj6 with EFI has:

  • coil terminal, 3 wires: Wht with 2 Blk stripes from down below (ign. amp.),
    Blk with 2 Wht stripes and Wht with Blk from harness.
  • coil terminal, 2 wires: Wht from down below (ign. amp.), Wht from harness.

Green wire to temp sensor for temp gauge, no rear sensor on rail.

Anyone, please let me know if something’s wrong with this too. Thanks,

Alex
79xj6

Peter Morris wrote:>

Yesterday, I fiddled a bit with the car, replacing a vacuum line and
repairing some brittle wires. I ended up using some plain automotive
wire (losing the color coding). While studying my repair manual and
the electrical manual, I couldn’t figure out what these wires were
attached to. The wires in question are:

  1. A pair attached to the negative terminal of the coil. One (White or
    maybe Pink/Black) goes to a bullet connector towards the end of the
    valve cover, and I think it’s probably for the tach? The other
    (Pink/Blue) disappears down below the intake manifold.

  2. There was a solid pink attached to the positive terminal of the coil.

  3. And there was a wire (Green/White) attached to a sensor on the
    water rail immediately aft of the coil. One book seems to suggest it’s
    the water temp sensor. Another shows a larger sensor, one location
    further aft, and states that’s the temp sensor. So what’s the sensor
    my green wire is attached to?

I really loved reaching down under the manifold! Particularly since I
had a valve cover leak up above…

Regards,

Peter Morris
Vista, San Diego County
California
'86 Jaguar XJ6 SIII
'78 Fiat Spider
'93 Ford Escort