This is an article for cleaning the IAT sensor on the 1998-2002 24V diesel engine.
The IAT sensor measures the temperature of the intake manifold. The ECM uses this sensor reading to set injection timing and adjust the air-fuel ratio. If the fuel mileage and power output of you engine seem low, some owners have found improvement in EGT, fuel economy, and power after cleaning carbon from the IAT sensor in at the rear of the intage manifold. Engine with exhaust brakes are particularly prone to IAT sensor fouling because soot is blown back into the intake during valve overlap. Smokingdiesel.com has an information page about problems caused by the IAT sensor.
The only tool you need is a 3/8″ ratchet with a 6″ extension and 13/16″ socket.
The IAT sensor is found on the driver’s side of the engine, almost at the back of the intake manifold.
Unplug the electrical connector from the sensor. You will need to spread the connect tab away from the sensor body to unplug the sensor. After the connector has been removed, use a 13/16″ deep well socket, 6″ extension, and ratchet to unscrew the sensor from the manifold.
The sensor on the left had 20,000 miles on it, and it was covered with soot. After a shot of carburator cleaner, you can see the sensor element inside the cage. Screw the clean IAT sensor back into the manifold, torque it to 10 ft-lb, and reattach the connector.
Pics below by Engcogod…
After seeing how much carbon was on after 20k I figured mine was going to be 5 times as worse being that my truck has over 130k on it. Too my surprise it really wasn’t bad at all. I’m sure it depends on what mods you have done & how you drive your truck. I got my truck used with 120k but don’t think the previous owner did too much maintenance to the truck, but I could be wrong. It doesn’t take long at all to clean the hardest part is getting it off the truck.
*Note – If you are double jointed the job will go a lot faster…. :)
Temperature |
Resistance |
30° |
40K |
32° |
30k to 36k ohms |
76° |
13K ohms |
77° |
9k to 11k ohms |
81° |
6.87K ohms |
122° |
3k to 4k ohms |
130° |
4K ohms |
167° |
600 to 675 ohms |
212° |
600 to 675 ohms |
Replacement Sensor:
[thanks to Fritz]Cummins PN 3408345
Dodge PN 05014197AA Sensor, Temperature (SEN, TEM)