I am embarrassed to admit that I have owned my LJ for nearly 10 years and I have only just now noticed that there is an intake sensor on my 4.0 that isn't plugged into the intake. While removing the throttle body for cleaning I was moving several wires out of the way when I found myself holding an obvious sensor of some sort that been tucked under the fuel injector wiring. It didn't take long to figure out that it was p/n 56028364AA, the Intake Air Temperature sensor. A little more digging revealed that there was no place on my intake manifold to plug the sensor into, even though my copy of the service manual clearly showed where it was supposed to go. The engine is at 130,000 miles and runs fine, no codes/CEL's, the only functional engine issues since I have owned the Jeep have been with the PCM connectors, which I replaced last year. For now I have simply tied the sensor up out of the way and left it connected to the wiring. The engine/PCM doesn't seem to care, so why should I?
The part in question. It was hiding under the fuel rail and caught me completely by surprise. It was dirty but apparently undamaged.
The connector for the IAT sensor, evidently part of the fuel injector wiring harness.
The intake manifold. According to the manual the IAT sensor should be plugged into a fitting screwed into the manifold in the area circled in red. Or not...
The part in question. It was hiding under the fuel rail and caught me completely by surprise. It was dirty but apparently undamaged.
The connector for the IAT sensor, evidently part of the fuel injector wiring harness.
The intake manifold. According to the manual the IAT sensor should be plugged into a fitting screwed into the manifold in the area circled in red. Or not...