2000 jeep grand cherokee oil pressure gauge high

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Table of Contents Show

What causes high oil pressure in a Jeep Grand Cherokee?
What would cause the oil pressure gauge to read high?
How long can I drive with high oil pressure?

09-09-2020

Oil pressure is determined by the resistance oil faces when flowing through the oil passages of the engine. Oil pressure is indicated by the oil pressure gauge and should show a steady value around 20 minutes after engine start-up, when the oil has reached its operating temperature. The unit of measurement is either PSI or Bar.

The ideal oil pressure varies depending on the car brand and model, but generally, the ideal oil pressure is between 25-65 PSI. To an extent, oil pressure is required for the oil to be able to reach all components of the engine, however if the oil pressure reading is outside of this range, it is usually considered too high or too low. Since the oil pressure depends on how much resistance the oil faces when flowing through the passages, factors like the size of the engine, the diameter of the bores, and the viscosity of the oil have an impact on oil pressure. A PSI over 80 is usually considered too high for the engine to properly be protected from damage. High oil pressure is an indicator that the oil is not able to properly pass through the bores and reach all parts of the engine effectively. An engine that is not lubricated correctly can face (sometimes instant) wear through friction, damage to its components, and in extreme cases, it can lead to engine failure.

What are the causes of high oil pressure?

Oil pressure sending unit malfunction: The oil pressure sending unit is responsible for measuring the oil pressure and controlling the oil pressure gauge on the dashboard. When the engine is cold, it is normal for the oil pressure to be higher. However, if the oil gauge reading is at its highest reading even after the engine has had time to warm up, the oil gauge may be defective. This can be diagnosed with a manual oil pressure tester, either at home or by a mechanic.

Dirty or contaminated oil filter: The oil filter is there to filter out impurities from the engine oil. Over time, particles from dust, soot, rust, and gum get deposited in the filter and begin clogging the system. This leads to more resistance and higher oil pressure.
Blocked passages: Once the oil has passed through the filter, it flows through a series of passages to the crankshaft. If these passages become blocked, the oil would not be able to pass through efficiently and effectively lubricate all parts of the engine. The resistance the oil faces in flowing through a partially or completely obstructed passage could be one reason for high oil pressure.
Relief valve malfunction: The purpose of a relief valve is to provide a place for the oil to flow when the pressure gets too high. Usually, these valves are set up to open and allow oil through once the pressure reaches a certain level of PSI. If the relief valve experiences a malfunction, the oil pressure can quickly rise to a level that is not safe for the engine.
Oil quality and viscosity: When oil is thicker (i.e: more viscous) it faces more resistance when passing through the engine's passages, leading to higher oil pressure. Changing the viscosity grade to a thicker or thinner oil has an effect on the oil pressure. If the oil is too viscous or not viscous enough, it might be the wrong oil for your engine. The temperature of the engine also has an effect on oil pressure. Since oil becomes thinner when it heats up, and thicker as it cools down, the oil pressure in the engine may be higher than normal during start-up. For this reason, it is recommended to wait 20 minutes after starting up the engine to gain an accurate PSI reading.

1. If a problem is truly gone, the check engine light will go OUT, but the code remains stored for a period of time unless you clear it. If you still have a light, you still have a problem. Read it again and post the EXACT codes here for comment. Don't describe the codes, post the exact code numbers. With OBD, the devil is definitely in the details and interpretation is very often NOT straight forward.

2. Most high oil pressure issues are not truly an oil pressure issue at all. They are the fault of the oil pressure sending unit, located directly above your oil filter. If you buy it, buy it directly from Jeep for the best reliability/accuracy/mating with your factory gauge. Well worth the extra $20....

3. For your bogging symptom, first review tuneup hardware status. Fresh Champion copper plugs gapped to .035, new plug wires, distributor cap and rotor. If symptom continues, clean both the throttle body and idle air control and test your "throttle position sensor". More on that below.
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.

The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -

NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!

• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted acordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the deined acceptable range causing the ECU to incorrectly fuel the engine. This is noticable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.

What causes high oil pressure in a Jeep Grand Cherokee?

Dirty or contaminated oil filter: The oil filter is there to filter out impurities from the engine oil. Over time, particles from dust, soot, rust, and gum get deposited in the filter and begin clogging the system. This leads to more resistance and higher oil pressure.

What would cause the oil pressure gauge to read high?

High Reading The pressure relief valve could be stuck or faulty, or there could be a blockage in the oil delivery lines. Since high pressure could cause your oil filter to burst, switch off your engine as soon as you notice the reading. Your car's gauges, indicators, and lights were made to help you!

How long can I drive with high oil pressure?

In this case, you should stop driving as the engine can only work for about 30 minutes without oil before complete failure, but even if you drive for 5 minutes the damage could be major and very expensive. What is this? If the oil level is high, the pressure relief valve near the pump and filter is probably stuck.

jeep grand cherokee oil pressure gauge high