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So I wanted to put together a series of posts briefly going over different areas of our Nitro's. This is a very basic overview of certain areas, but that's where we need to start.

In this first post I have pointed out some very basic underhood components. This is only a short list and anyone who has questions on components not listed or further technical descriptions please ask here. :smileup:

I don't have a picture of the 4.0L, but there are no differences in the components I've listed.

1. A/C Expansion Valve

The A/C expansion valve controls the high-pressure, low temperature liquid refrigerant from the A/C liquid line and converts it into a low-pressure, low-temperature mixture of liquid and gas before it enters the A/C evaporator. A mechanical sensor in the A/C expansion valve monitors the temperature and pressure of the refrigerant leaving the A/C evaporator through the A/C suction line, and adjusts the orifice size at the liquid line port to let the proper amount of refrigerant into the evaporator to meet the vehicle A/C cooling requirements. Controlling the refrigerant flow through the A/C evaporator ensures that none of the refrigerant leaving the A/C evaporator is still in a liquid state, which could damage the A/C compressor.

2. Heater Hoses

3. Transmission Fill Tube (No Dipstick included - Special Tool Required)

4. Exhaust Gas Recirculation Valve/Soleniod (EGR) is used to reduce the amount of NOx created by the engine. It does this by diluting the air/fuel mixture with a small amount of inert gas (usually less than 10% of the total mixture); exhaust gas is used since it contains only a small amount of oxygen (and is readily available). Adding it has the effect of lowering the combustion temperature below the point at which nitrogen combines with oxygen to form NOx. When working properly, the EGR does not open when the engine is cold, at idle or WOT. A defective EGR can have a severe impact on the quality of idle.

5. Engine Oil Dipstick

6. Intake Air Temperature Sensor

7. Fuel Supply Line

8. Engine Oil Filler Cap

9. A/C Compressor

The A/C compressor is driven by the engine through an electric clutch, drive pulley and belt arrangement. The A/C compressor is lubricated by refrigerant oil that is circulated throughout the refrigerant system with the refrigerant.

The A/C compressor draws in low-pressure refrigerant vapor from the A/C evaporator through its suction port. It then compresses the refrigerant into a high-pressure, high-temperature refrigerant vapor, which is then pumped to the A/C condenser through the compressor discharge port.

10. Alternator

11. Power Steering Fluid Reservoir (requires ATF+4 fluid)

12. EVAP/Purge Soleniod

The solenoid regulates the rate of vapor flow from the EVAP canister to the throttle body. The PCM operates the solenoid.

During the cold start warm-up period and the hot start time delay, the PCM does not energize the solenoid. When de-energized, no vapors are purged.

The proportional purge solenoid operation is controlled by an engine controller circuit that senses the current being applied to the purge solenoid and then adjusts that current to achieve the desired purge flow. The purge solenoid controls the purge rate of fuel vapors from the vapor canister and fuel tank to the engine intake manifold.
Thank you for the detail...
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