Crank Position Sensor

[Clifford Pope]

I am posting this just in case of general interest.

This morning the car suddenly cut out without warning, and wouldn't restart.
I checked fuses, then replaced the fuel pump relay and Ignition Amplifier Module, but to no avail.
After more fruitless turning, giving up, then trying again, it sort of stumbled into life, and I was able to limp back home, cutting out once on the way.

Knowing that the next on the list is the Crank Position Sensor, I replaced that, having fortunately a spare one at home, and the engine immediately sprang into life. A test run confirmed all is well.

The CPS had cracked insulation around the wires just by the sensor itself, and was surrounded in muck as a result of a long-standing small coolant leak from the heater pipe behind the engine. (see other thread).
So the leak had undoubtedly contributed to the failing.

It was interesting that the car I realise now runs much better than in recent months. I had thought of the CPS either working or not working, but it seems a slow deterioration can simply take the edge off performance long before it actually fails.
Suddenly the car pulls much better at lower revs.

So perhaps replacement ought to be a regular preventative maintenance item?

The best way to get at the CPS I found was to loosen the 10mm bolt with a small ring spanner, then use a small 10mm socket to give a better grip to one's fingers.
The best position is to stand on the nearside of the car, facing forwards, and use the thumb and 2nd finger of the right hand to turn the socket.
1st finger doesn't work because the knuckle is too close to the thumb and rubs on the bulkhead.

Re-starting the bolt after replacement is tricky. Spread something underneath to catch it if (when!) you drop it. Having got the threads engaged, change to the socket in fingers as far as possible, then tighten with the ring spanner.

Possibly a series of socket extensions with universal joints would work, but they would need to be 1/4" drive and very slim to fit down the back.
I did find a long snake-like flexi-connector in my tools box, but unfortunately with a hexagon not square end, so no use for anything.

[stephend]

Out of interest, which engine has yours got?

[Clifford Pope]

Originally Posted by stephend

out of interest, which engine has yours got?

b230f (1992)

[Derek UK]

When refitting, use some Blu-Tak to hold the bolt in the socket. Clean bolt and socket with brake cleaner to maximise the sticking properties.

[heckflosse]

I have had them seize in the housing, which can even mean 'box out, so be gentle...
TDC sensors do go wrong, there were even recalls for them back in the day, as the saying goes.

[Clifford Pope]

Originally Posted by Clifford Pope

stand on the nearside of the car, facing forwards,

I've just re-read that.
What I meant of course was stand beside the car on the near side, not stand ON the car.