Timm's M60/M62 Camshaft Sensor Replacement

So, there I was, trundling along nicely when the engine decided to produce absolutely no power at all - then it pickup again - and then it stopped again, you get the picture. Pulled off the road and the engine stopped dead. It would start again, sound OK for a few seconds, then make awful popping noises and fizzle out. There was also a smell of raw fuel from the exhausts - it certainly seemed electrical rather than a fuel starvation problem. So, engine covers off, camshaft sensor loom disconnected from the Bank 1 loom box and the engine would run again. Not a great deal of power but enough to get me back on the road again.

Disconnecting the camshaft sensor makes the engine run in 'wasted spark' mode where the plugs fire every rotation of the crankshaft, as there is no camshaft signal, the timing information is taken from the crankshaft sensor which does not have information regarding the current camshaft cycle  - this means that the plug will fire at the top of the exhaust stroke as well as at the top of the compression stroke, hence the 'wasted spark' name. It also means that the injectors will fire on each crankshaft rotation rather than on the induction stroke. This wastes fuel and reduces power - but it does mean you can get home.

If the camshaft sensor completely fails while you are on the road, the engine will stop - but it will run again when re-started in wasted spark mode. However, if the sensor produces a signal when the engine is re-started and then that signal is lost, the engine will do what mine did - go one second and then fizzle out the next. Right, let's get on with it.

Only purchase the sensor from BMW, the copies often fail to work at all, or worse, produce erroneous signals, especially at higher revs. This seems an unnecessary expense as surely the copies work - I'm afraid that a lot of them don't, and at 100 it is an expense worth paying. The part number for my '99 M62 is 12141742185 and the o-ring is 12141748398:

Loosen these two large Jubilee-clips:

Remove the engine cover and the acoustic insulation (10mm nuts on the E31/E32, quick-release buttons on the E38):

Loosen the ICV hose Jubilee-clip and carefully pull the hose from the valve:

Disconnect the camshaft sensor loom at the front of the wiring box above Bank 1 by pushing the metal clip inwards and lifting:

Remove the large-bore inlet section from the throttle body and MAF - note that there is a clip that secures a loom behind the hose:

Using an Allen-key, remove the single bolt securing the camshaft sensor (sorry for the poor picture), then twiddle the sensor out of the cavity:

Carefully unthread the loom from the tangle of cables, unclipping it from this clamp:

...and slipping the connector behind the dipstick tube:

Before there is a chance of getting dirt in the timing case - use silicone grease on the new o-ring and insert the sensor:
P.S. It's a darn sight easier greasing the o-ring when it isn't fitted to the sensor - but I only remembered to stage the picture later

The single Allen bolt has Loctite on the threads, this usually remains active enough to stop the bolt coming undone. However, if there is any doubt, use Loctite 222 on the threads for security. The bolt only needs to be nipped-up, the Loctite stops it coming undone. Tightening too much may damage the sensor:

Thread the loom back behind the dipstick tube, under the other looms, remembering to clip the loom in place here:

And then plugging the sensor back in:

Lubricate inside of both ends of the large-bore inlet pipe and the hose that goes onto the ICV with silicone grease - get the pipework in position but ensure that the loom that clips into the back of the pipe does not get trapped underneath the pipe:

Pop all three ends in place and nip-up the Jubilee-clips, they don't need much pressure to be held in place. Fit the (optional) cruise-control cable over the ICV hose and clip it into this clamp :

Refit the acoustic layer and the covers and that's it. It is best to clear the error code with diagnostics, but the DME will accept the signal from the new camshaft sensor anyway.

All done, time for a cup of tea


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