Thread: 2000 Discovery 2 TD5 - Wont start after head gasket replacement :(

Have you had had the sensor out sometimes they are not at
the correct depth.
They will run but not rev past 2500

How to test
Resistance [Ohm]: 1290,

The CKP sensor is the only sensor on the TD5 that does not have a default in ECM if the sensor or wiring are damaged the engine will NOT run.

The ECM measures the outputs from the CKP.
The values expected from a good CKP sensor
are as follows:
2 to 3 volts with engine cranking.
Rising to 6 to 6.5 volts from 1000 rev/min upwards.
The above readings are dependent upon correct air gap between the tip of the CKP sensor and the passing teeth of the reluctor ring.

How to check the CKP sensor's wiring.
Common faults are damaged wires or oil contamination.
Unplug the ECM red plug (C0158) and check between pins of the sensor connector...it must be open circuit.
then bridge the pins in it and measure between pins 13and 36 of red plug ... this must be closed circuit.

How to check the CKP sensor's output take out the ECM as to have access to C0158(ECM red plug)
set voltmeter to AC up to 10V range, dont disconnect the plugs,
identify Red/live on pin13(pink/black trace wire)
Black/negative on pin36(white/blue trace wire),
insert a thin sewing needle through the insulation in each wire as to reach the 'core' and measure on the needles while somebody cranks the engine.
You must read between 2 - 3 V (AC) there... different voltage would not allow ECM to start the engine.

Hope this helps

I have done my head gasket replaced did it myself and it took a lot of cranking to get it to fire I put it down to the injectors being full of air and taking awhile to self bleed.


In reply to above post it is never a good idea to poke holes in the insulation as this allows moisture to get in and corrode the wiring can be a pain to fault find later on as I have repaired a few faults for this very reason.

thanks again guys,
i replaced the crank angle sensor today, as well as all the glow plugs (all tested bad)
engine now coughs and splutters, but will not start, UNLESS i spray some aerostart into the intake. In this case it will start, idle around 1000rpm , pressing the accelerator does nothing and the engine is making a horrible knocking noise - and blowing a hell of a lot of white smoke out the exhuast.

Will run the checks on the wiring scots , but it does seem to me like the ecm is trying to start the engine...

im really at my wits end with this - i double checked my adjustments on the injectors and im sure they are correct!

I read a article about a td5 not starting and when they could fire it up it would cough n splutter, ended up being the injector harness oil problem iirc

check the wiring to the crank angle sensor.

Ive been caught out by nudging it about and breaking a wire inside the corro wrap before today...

but by your last post, its sounds like you have the cam a tooth or 2 out.


the field check I use for combustion gasses into the fuel tank is to fill the tank to the absolute brim and then start it, if it blows bubbles up the fillerneck then you have a combustion leakage problem into the injectors.

if you have froth on the top of the injectors once its started you have a body seal issue.

its also worth trying a leak down test. (on the 4 pots you can pull the glow plugs from.

ill check the wiring tomorrow but i am starting to suspect the fuel pump and/or regulator is faulty.
Although there is fuel coming out of the hose going into the regulator when i disconnect it and turn the ignition on, perhaps the pressure isnt enough.
Does anyone know how i would go about testing fuel pressure on these cars - there doesnt appear to be a test port.
Also what pressure should i be getting ?

Im thinking a fuel pressure test kit would be a wise investment!

Tank to FPR should be arround 6bar after FPR 4bar if you can get
a oil pressure gauge hooked up to a m14x1.5 male conection you
can just unscrew fuel temp sender in the FPR should be 4bar
guage needs to be rated more than expected so use 10bar gauge.

If you have an old FPR or cooler you could make up a quick connect
gauge using the pipes from FPR/cooler ideal for testing pump and
fuel in head pressures.