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Replaced the crank sensor. Still won't start.

newjeepowner

NAXJA Forum User
Location
Roseville, MI
Saturday I was driving home and the check engine light came on. Got home and parked it. 3 hours later got in it and would not start. Borrowed a scan tool and got a Crank sensor error. I disconnected the battery and then climbed underneath to install a new sensor. Reconnected the battery which cleared the engine light. Tried starting it. Would not fire up. Does not seem to be getting spark from the coil. No check engine lights have come up. What should I do/replace next? This is on a 1999 with a 4.0
 
Ensure that the "connector" for the crank sensor is clean. A can of spray electrical contact cleaner is good for that purpose. Also, there is a crank sensor connector inside the engine bay near the firewall/#6 injector. Unplug that and clean that too. If it is dirty, it can inhibit the crank sensor signal from making it to the computer.
 
Cam position sensor will do this. If it goes out while the engine is running, the ECU uses a pre mapped curve to run the engine. This will work until the engine is shut off, then it will not re-start.
 
Cam position sensor will do this. If it goes out while the engine is running, the ECU uses a pre mapped curve to run the engine. This will work until the engine is shut off, then it will not re-start.

It was the cam sensor/pickup coil. The little magnet fell off the unit. Thanks everyone.
 
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