can i by pass my crankshaft positioning sensor on my ztec engine it keeps getting worn down

I believe that sensor is needed for spark timing.

I don't think it wqill run without it. What's wearing it down? I didn't think anything touches it.

It shouldn't be touching anything. I have never had one go bad either.

How do you know it needs to be replaced?

It shouldn't be touching anything. I have never had one go bad either.

How do you kno w it needs to be replaced? the car wont crank does the crankshaft touch it

The CPS sends an electrical impulse to the ignition control unit. I don't think it has anything to do with cranking.

Have you checked for codes, gotten a check engine light? The CPS/CKP if not working right will create codes. I thought it is thru bolted so it shouldn't rub the crankshaft trigger wheel. Is yours different? Is it coming loose? It is not clear to me when reading the purpose of the CPS, that it is used when starting and without it, it wouldn't start. Quoting chapter and verse:

The Ckp sensor provides information on crankshaft position and the engine speed signal to the PCM. It detects when the engine is at TDC so that the PCM can control ignition spark advance. The CKP is also part of the misfire monitor circuit. You should have battery voltage at the disconnected sensor with key on eng off. You can use an ac voltmeter connected to the sensor to measure voltage fluctuations when turning the crankshaft slowly with a wrench. No reading, bad CKP.

Your starter won't turn it or it won't fire? You may have ignition issues - plugs, wires, coil. Starter, battery, wire connections. Hows battery voltage, spark? Try starting fluid.

Please elaborate more on your problem.