Engine sensors

Since my Jeep Liberty is a diesel I have experienced first hand the negative effects emissions controls can have. The soot from the EGR system mixed with the oil vapor from the crankcase ventilation creates a sludge that ruins sensors. During my HDT research I paid special attention to recommendations about the engine sensors.

A positive aspect about the Cummins ISX 870 I have is the crankcase is vented to atmosphere and not mixed with the soot. Soot is still a concern and will eventually block sensors and/or cause degraded performance. The pressure sensors on my motor appeared to be the originals so I decided to replace them. I cleaned the temperature sensors. All the pressure sensors were restricted with soot but as far as I could tell they were not blocked.

The Intake Manifold Pressure (MAP) sensor is on the right and very easy to get to. The original part number is 4087987, but the lastest P/N is 4928593. The other sensor is the Intake Manifold Air Temperature sensor. I cleaned it off and it looked good as new.

The Exhaust Gas Pressure sensor (P/N 4928594) was a little more work. I had to remove the air filter intake tube.

I also cleaned the tube that feeds the exhaust gas pressure sensor and the tunnel in the block that leads to it. I used carb cleaner and blew it out with compressed air. They needed cleaned. The tunnel in the block was almost closed shut.

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