AW4 sensor questions

OK I dont know what this sensor is but here is the deal. I took the transmission out last week well some how I lost this rubber piece that sits will a sensor that sits on top of the bell housing. The sensor runs from the flywheel and plugs in up by the throttle body, and it attaches to one of the studs on the fuel rail. Ok so is that the TPS? What I really need is that rubber piece does anyone know where I can get it?

That sensor is the Crankshaft Position Sensor (CPS) and is used by the engine computer to determine just about everything regarding the rotational speed and position of the crankshaft. You lost the rubber plug that fills the gap between the sensor and the bellhousing - I'd recommend you try to find one in a junkyard just to keep crap out of that area.

More info - http://www.yuccaman.com/jeep/cps.html

That sensor (should have been at 11:00 on the bellhousing, looking forward) is your Crankshaft Position Sensor (CPS) and you just CAN'T run without it! Its signal is used by the ECU/PCM to generate basic fuel injection and ignition timing.

That "rubber bit" you lost was probably the dust plug for the sensor hole - I've not seen one in person yet. Is it necessary? Given that I've got five XJ's that all run just fine without that plug, I don't think so. If you keep tossing crap up on top of the bellhousing, you might want to think about replacing it, but I haven't bothered yet. I'm fairly sure it's OEMR only tho - certainly haven't seen it anywhere loose.

If it makes you comfortable, you should replace it - but I haven't bothered to just yet. Maybe later...

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Ok thanks for the advice maybe I will get one soon but I need to get my Jeep running. So I will put the sensor and hope it runs.

It should run without the cap - as long as you haven't screwed up the sensor itself. As I'd said, I've got five rigs, and none of them have that cap - so it's not functionally necessary. You can always stick it in later, once you pick it up.

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