Repair 7

When the oil pressure starts to drop in a diesel engine, problems set in. First, the oil is not fully spread across the engine, which contributes to further problems. Shaft bearings start to wear as a result, including the camshaft. Piston rings start to wear, leading to excessive oil burning. Overall, a snowball effect takes place, leading to eventual engine destruction. When the oil pressure goes low, all additives claim to "fix" the problem instantly. Correctly fixing the problem, however, involves extensive diagnosis, including analyzing the oil pump closely.

False Claims

Low oil pressure in a diesel engine indicates something is seriously wrong. Trying to use additives to correct low oil pressure is like putting a band aid on a broken leg. Some additive makers have been known to make false claims of correcting engine problems. For example, the Federal Trade Commission in 2001 brought charges against Zmax oil additive for deceptive advertising.

True Causes

The true causes of low oil pressure in a diesel engine are serious. First, check the oil level and type of oil you are using. The oil should be rated for diesel engines, and the proper viscosity must be used. The service department of the dealership that sells your make and model of vehicle can help you choose the right oil. If you are using the right oil, the next step is to suspect a faulty oil pump. Furthermore, Machinery Lubrication Magazine states that diesel fuel dilution causes low pressure at startup. A qualified diesel technician can assist you in diagnosing and correcting the problem.

Simple Cures

If the oil pressure is a little low, try some simple fixes. Using a thicker viscosity of oil might help. For example, suppose the manufacturer calls for using 5W-20 to 20W-30 for the oil weight. If you use 20W-30, this is slightly thicker. You are still staying within the recommended guidelines, but are using oil at the upper range of the recommended thickness scale. If you suspect fuel dilution, drain and change the oil and oil filter. This will get rid of the thinned out oil. You oil pump may be sensitive to changes like this, and perhaps the problem will self correct.

Steps To Take

Try the easy solutions first. If the oil pressure is just starting to go low, you may have to change the oil more often to overcome fuel dilution. Try to start your engine less frequently, as the experts state this leads to fuel dilution, particularly in cold weather. If the simple solutions do not resolve the problem, then professional expertise is needed to diagnose the root cause of the problem. Additives claim to correct problems, but these claims should be looked upon with skepticism.

The SRT-4 is a sportier version of the Neon that the Dodge division of Chrysler produced from 2003 to 2005. The primary difference between the SRT-4 and the base model Neon is that the 4-cylinder 2.4-liter engine in the SRT-4 is turbocharged. This does not affect the fuel pressure regulator installation, as this procedure is the same for all Neons made from 2000 to 2005. The fuel pressure regulator in an SRT-4 is part of the fuel filter assembly.

Instructions

1

Remove the filler cap on the fuel tank to relieve the vapor pressure in the fuel tank. Take the relay for the fuel pump out of the fuse box located in the engine compartment.

2

Start the engine and let it run until it stalls. Repeat this procedure until the engine fails to start to ensure you have removed the fuel from the fuel system. Detach the cable from the batterys negative terminal with a socket wrench to ensure you dont start the engine while replacing the fuel pump.

3

Press down on the quick-connect fittings for the fuel line and disconnect the fuel line from the fuel filter. Hold the locking spring tab on the fuel filter down and turn the fuel filter 90 degrees counterclockwise. Detach the fuel filter from the fuel pump and discard the fuel filters O-rings.

4

Lubricate the new fuel filter O-rings with engine oil and place them on the fuel filter. Place the fuel filter into its socket on the fuel pump so that the the hold-down tabs on the fuel filter align with the fuel pump flanges. Hold the fuel filter down as you turn it 90 degrees clockwise to lock the fuel filter into place.

5

Connect the fuel line to the fuel filter, then attach the cable to the batterys negative terminal with a socket wrench. Start the engine and check for fuel leaks.

Toyota has used the Celica name for a variety of sedans since 1970. The most recent version of the Celica is a 3-door hatchback that was in production from 1999 to 2006. These vehicles have 4-cylinder, 1.8-liter engine with multi-port fuel injection. The fuel pressure regulator in a late-model Celica attaches to the fuel filter and is accessible with an access panel under the rear seat. The replacement of the fuel pressure regulator in a Toyota Celica also requires the removal of the fuel pump assembly.

Instructions

1

Open the gas cap to relieve the pressure in the fuel tank. Disconnect the negative battery cable with a socket wrench to avoid starting the engine accidentally. Remove the rear seat cushion and disconnect the screws on the service hole cover. Remove the service hole cover.

2

Detach the electrical wiring to the fuel pump assembly. Disconnect the fuel outlet pipe from the fuel pump bracket with tool SST 09631-22020. Remove the retaining screws for the fuel pump bracket with a socket wrench and detach the return hoses from the fuel pump bracket. Pull the fuel pump assembly from the fuel tank.

3

Remove the fuel suction support from the fuel pressure regulator with a socket wrench and detach the fuel pressure regulator from the fuel filter. Remove and discard the O-ring for the fuel pressure regulator.

4

Coat the new O-ring with a thin layer of gasoline and mount it on the new fuel pressure regulator. Attach the fuel pressure regulator to the fuel filter and install the fuel suction support.

5

Install the fuel pump assembly into the fuel tank and connect the return hoses to the fuel pump bracket. Fasten the retaining screws to the fuel pump bracket and connect the fuel outlet pipe to the fuel pump bracket with tool SST 09631-22020.

6

Attach the electrical wiring for the fuel pump assembly. Replace the service hole cover and fasten the retaining screws for the cover with a socket wrench. Install the rear seat cushion and connect the negative battery cable.

A vehicles oil pressure switch keeps track of the oil pressure that the oil pump creates. This is important because low oil pressure can severely damage a vehicles engine due to the fact that the engine needs adequate lubrication at all times.

Functions

On older model vehicles, an oil pressure switch will send a signal to the oil pressure light. This warning light comes on when the car is cranked but goes off as the pressure builds. The oil pressure switch on newer model vehicles will signal its computer, which can cause a car not to start if it has low oil pressure.

Pressure

In addition to an oil pressure warning light, some automobiles also have a gauge which the oil pressure switch can inform of the vehicles current oil pressure levels. The pressure levels typically range from about 7 psi to 12 psi when the automobile is idling and 40 psi to 60 psi when the automobile is being driven.

Tips

When it has been determined that an oil pressure switch needs a replacement, there are a few things that should be done in advance. Have a reputable mechanic check that oil levels are correct. The vehicles oil pressure should also be checked to make sure it matches specifications required by the vehicles manufacturer.

The fuel system pressurizes fuel from the fuel tank to the engine. Fuel-injection systems meter the fuel injected for the cylinders by controlling the length of time the injectors are open. To inject the correct amount of fuel, the pressure must be constant. The fuel pump contains a check valve to ensure a rapid start next time the vehicle is started by maintaining fuel pressure throughout the system. Depressurize the fuel system to prevent spraying highly flammable gasoline before replacing fuel system components such as a fuel pump.

Instructions

Stall Method

1

Place the vehicle in park. Set the parking brake to prevent vehicle movement. Open the hood.

2

Open the gas filler door. Remove the gas cap to relieve fuel vapor pressure from the fuel tank.

3

Locate the fuel pump fuse. Generally, the fuel pump fuse is located in the underhood electrical distribution center near the battery. Remove the plastic cover protecting the distribution center. The fuse location should be labeled on a diagram on the plastic cover.

4

Start the vehicle and allow the engine to idle. Remove the fuel pump fuse. The engine will run normally for several seconds. The engine will start to hesitate and misfire. Allow the engine to stall.

5

Turn the ignition key off. Disconnect the negative battery cable with a metric wrench to prevent accidental re-pressurization of the fuel system.

Fuel Gauge and Test Port Method

6

Park the vehicle. Engage the parking brake to prevent accidental vehicle movement. Open the hood. Disconnect the negative battery cable with a metric wrench. Open the fuel filler door. Open the gas cap to relieve pressure inside the gas tank.

7

Locate the fuel pressure test port. The test port has a screw on protective dust cap and looks almost exactly like a tire valve stem. Remove the protective dust cap by hand.

8

Place a rag around the fuel test port to catch fuel leakage. Screw the fuel pressure gauge onto the fuel pressure test port.

9

Place the end of the clear plastic line of the fuel pressure gauge into a gas can. Depress the pressure relief button on the fuel gauge to bleed the fuel system pressure into the gas can. Release the valve. The fuel pressure gauge needle should register zero.

10

Remove the fuel pressure gauge and reinstall the dust cap on the fuel pressure test port.