Si Click

Well-Known Member
A week or so ago my son's D90 TD5 (10p) lost power, the MIL came on and it threw up a code along the lines of poor crank position signal high. It was close by and driveable at slow speed so it limped home.

When I swapped in a new crank position sensor the plug off the loom basically came apart in my hand. The wire was heavily corroded and one became completely disconnected, I put the failure down to dodgy wiring but left the new sensor in place just in case. There was very little uncorroded wiring from the loom, and trying to crimp terminals to what was left and assemble a new socket in the cramped space behind the engine was impractical. So I acquired some twin core screened cable specified as suitable for CPS, wired it into the ECU plug (including the earth screen), armoured it, routed it neatly to the sensor with a new plug. At each end I kept the screening in place as close as possible to the plugs. All seemed well.

I then replaced the exhaust manifold (which did not go so well), also installing a pyrometer for a 52mm EGT gauge which replaced the clock in the dash. I test drove it for about 5 miles and it was fine.

My son picked it up this afternoon and as soon as the engine started the MIL came on with the same poor crank position signal high code. However, this time there is no loss of power and the MIL is intermittent, not illuminating on every start.

The new sensor is an aftermarket one from Bearmach, so I guess it could be faulty out of the box. If it is still throwing up codes next weekend I will put the old sensor back on.

The only other thing I can think of is that the wire I used has too low a gauge. It certainly seemed thinner than the original wiring. Does anyone know exactly what specification the wire should be and where I can get more suitable screened wire? This is the wire I used; https://www.efi-parts.co.uk/index.php?productID=324

Any other thoughts as to what the problem might be?
 
Does anyone know exactly what specification the wire should be and where I can get more suitable screened wire?
I doubt that the wire's gauge is the problem there, it's rather a contact or bad sensor issue provided you didnt mix up the polarity
 
Another problem which will yield similar symptoms is failure in the wiring loom between the accelerator pedal (or 'driver demand') and the ECU. I know because it happened to mine. So it could be another fault happening simultaneously rather than the same thing. Land Rover seemed to have a batch of wire that is apt to go very brittle - both the insulation and the conductors - in the TD5 period.
 
I doubt that the wire's gauge is the problem there, it's rather a contact or bad sensor issue provided you didnt mix up the polarity

You were right. I replaced the new sensor with the old one and the fault has cleared and not returned. Another thing to add to the list of things not to buy aftermarket. Glad I put the old one aside as a spare rather than binning it.
 
Another thing to add to the list of things not to buy aftermarket.
yes, the CPS is way too important to mess with aftermarkets, though this is universally valid when it comes to any sensor involved in the engine management. I'm glad it's sorted
 

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