32 minutes ago, cycleguy said:

would you know off hand what inpedance reading that sensor should be ?

It will be an electronic unit, connections are:

1 VOUT. Will be a voltage, probably in the range 0v to about 4.5v when the sensor has VREF applied.

2 Gnd. Should be the car earth.

3 VREF: Should be 5v when the ECU is active.

Connector pic below.

So any ohms readings will be highly dependant on the multimeter used, and are not diagnostic unless comparing a suspect unit to a known good unit with the same multimeter. (Multimeters use different voltages to energise circuits when testing ohms.)

The best way to test it would to the backprobe the signals with the ignition on, and either engine off (no DP) or engine idling (some small DP). Backprobing with the engine at full power is not very practical! It involves inserting a thin needle down next to the wire from the back of the connector to touch the crimp terminal inside. Google can explain better.

Alternatively, many diagnostic systems, including Forscan, can display the signals as read by the ECU in real time. This can be used up to full power, max gas flow, so max DP.

 

if it wont run after changing the fuel filter. pop the breather hose off the inlet pipe to the turbo and spray something flammable down it like break cleaner whilst you crank the engine over on the key. it will cough splutter and run on the cleaner till it pumps enough diesel through to run on that. don't spray too much or it will rev the engine up a lot.

 

dirty fuel filter cause all kinds of weird faults.

For what it's worth ... I had random "limp" problems with my Mk2 1.6 Diesel and after many attempts at diagnostics and  changes I took the advice of a bloke and had the glow plugs replaced (despite tests saying they were perfect). I thought it cheap enough to try. And yes, it fixed it.  Then the turbo went (again) but that's a different story.

 

1 hour ago, mredowns said:

For what it's worth ... I had random "limp" problems with my Mk2 1.6 Diesel and after many attempts at diagnostics and  changes I took the advice of a bloke and had the glow plugs replaced (despite tests saying they were perfect). I thought it cheap enough to try. And yes, it fixed it.  Then the turbo went (again) but that's a different story.

 

From reading these forums over the course of a few years, it seems that a change of fuel filter of glow plugs sorts many problems relating to EML or sluggish running...and it has worked for me both times I have had such issues.