Finding the CKP Sensor:
* 4.0L Inline-6 Engine: The CKP sensor is usually mounted on the engine block, near the passenger-side (right-side) of the bellhousing, fairly close to the crankshaft pulley. You'll likely see a single-wire connector attached to it.
* 2.5L Inline-4 Engine: The location is similar to the 4.0L, but specifics might differ. You'll need to consult a repair manual specific to your engine for precise placement.
Replacing the Crankshaft Position Sensor:
This is generally considered a relatively easy job, but always disconnect the negative battery terminal before starting.
1. Locate the Sensor: Use the information above to find the CKP sensor. A repair manual with diagrams is highly recommended for precise location.
2. Disconnect the Electrical Connector: Carefully unplug the electrical connector from the sensor. Sometimes, it helps to spray a bit of electrical contact cleaner into the connector before disconnecting.
3. Remove the Sensor: The sensor is usually held in place by a bolt or a couple of bolts. Use the appropriate size socket and ratchet to remove these bolts. It may be a bit tight, so use a breaker bar if needed.
4. Clean the Mounting Surface: Once the sensor is removed, clean the mounting surface on the engine block. Any debris or old gasket material could interfere with a proper seal on the new sensor.
5. Install the New Sensor: Carefully install the new crankshaft position sensor, ensuring it seats correctly. Tighten the bolts to the manufacturer's specified torque (check your repair manual).
6. Reconnect the Electrical Connector: Firmly plug the electrical connector back onto the new sensor.
7. Reconnect the Battery: Reconnect the negative battery terminal.
8. Test the Vehicle: Start the engine and ensure it runs smoothly. If you have a code reader, scan for any diagnostic trouble codes (DTCs).
Important Considerations:
* Repair Manual: A repair manual specific to your 1991 Jeep Cherokee (including the engine size) is incredibly helpful. It will have detailed diagrams, torque specifications, and troubleshooting steps.
* Tools: You'll need basic hand tools, including sockets, a ratchet, and possibly a breaker bar.
* Safety: Always disconnect the negative battery terminal before working on any electrical components.
* Sensor Type: Make sure you buy the correct crankshaft position sensor for your specific 1991 Jeep Cherokee engine. Using the wrong sensor could lead to further problems.
If you're not comfortable performing this repair yourself, it's best to take your vehicle to a qualified mechanic. Misdiagnosis or improper installation can lead to more extensive damage.
