Yes,the magnet is pressed into the end of the compressor nut. I've run the sensor in a few different positions and it doesn't appear to matter where you bolt it in at. However, it is recommended that it be just counter-clockwise to the main fuel pipe. The main thing is that the sensor is positioned as close to the top of the retaining bolts as possible as to get it as close to the end of the compressor nut as possible. For the best performance from the rpm sensor twist the Glow Plug wires like a rope and then route them as far away from all other wiring as possible. Check the connector end of the EGT probe. If the wires are just crimped, soldering them to the connectors will avoid any intermittent operation down the road.

<span style="color: rgb(153, 51, 0);"><span style="font-family: Verdana;">"Just out of interest, does the sensor pick up the north and south poles of the mag or just the one, I was just wondering how the system works..."</span></span><span style="font-family: Verdana;">
</span>
I do believe the sensor detects the vairation between the north and south pole so it needs both.

Xwing