So replaced my crankshaft sensor and now it’s idles really rough! Could be a bad sensor? Is it possible that it jumped timing?

 

OEM sensor ?

Was the sensor bought from a legit vendor? Amazon & eBay are full of crooks nowadays.

 

Got from advance auto parts. Really weird. It was running fine before I changed the sensor.

 

Wire might be melting on exhaust after installing new one

 

Could the computer have learned the old sensors habits and its trying to learn the new one? Or does that sensor not have any effect on that stuff and the computer just reads what the sensor is putting out...???

 

Why did you replace it? If the OEM crank sensor wasn't bad, I'd put it back in.

The Chinese sourced sensors are very poor quality, and lots of people have posted about getting bad ones right out of the box. What year? The Renix is more sensitive to quality and wiring. A weak sensor will have issues starting and idling but run okay at high rpms. You could also try the mods that Cruiser54 recommends at http://cruiser54.com/?p=50 to move it slightly closer to the flywheel..

 

Aftermarket crank sensors are, for the most part, crap. Weak magnets. They might last a couple minutes, months, years, or die as soon as you turn the key. Thats how unreliable the aftermarket crank sensors are. However, crank sensors for older XJ are getting harder to find so aftermarket is becoming the only option.

I am curious as well. If it was running fine before replacing it, why was it replaced?