Have checked the Crankshaft Position Sensor (CPS) and it has shorted out. What do you need to do to replace this part?

* Buy a new position sensor. When you match the new part to the one on the engine, you'll see what you're up against. It's not a difficult job. Just a little time consuming to route the nearly 3ft of attached cable under the intake manifold and over to the ignition control unit. The little "omega" clips that position the cable will probably break, so you might want to pick up 4 or 5 of those.
* Don't try to splice the cable. Replace the new sensor with it's new cable, just as it comes in the box. There's an allen head bolt holding the sensor itself. Get a good fit with your allen socket; i.e. don't round out that bolt head. Once the bolt is out, if the sensor is hard to get out, use some penetrating oil and work the sensor back and forth, gently pulling it out as you go (of course, you've already removed the oil filter to make more room). Then, with a bore cleaning wire brush, clean out the sensor bore. The new sensor should slide in easily.

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ASE Master Tech
Quality Enterprises
Mercedes Svc. & Restoration
Sheridan, IN
317.769.3536

Sadly there are two parts known as the CPS, one goes to the front of the crankshaft, the other goes from the EZL on the left fender well down to the top of the bell housing.

* The second pick-up, the one that lives on the timing cover next to the front crank pulley, should go directly to the diagnostic plug X11. It forms pins 7, 8, and 9 and doesn't connect to anything else in the car. If you have the appropriate tester, you can read rpm (anything else?) with it. I read rpm a different way so don't use pins 7, 8, and 9.
* I've never encountered the need to replace the sensor on the front crank pulley. But the position sensor (L5) at the back of the motor is a common problem and my comments refer to that. Sorry for any confusion.

__________________
ASE Master Tech
Quality Enterprises
Mercedes Svc. & Restoration
Sheridan, IN
317.769.3536

Thanks for the input!!

When I did mine (or tried to atleast) it was easier to get to the sensor from underneath the car.

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87 300E
202k on the clock