Understanding Fuel Pressure: Cfe0113 Pump Performance

The Delphi Gasoline Fuel Pump CFE0113 is an electric fuel pump designed to operate under extreme temperatures and quick engine starts, including with alcohol fuels and blends. The Delphi CFE0113 is a standard replacement pump that comes with a wiring harness and is designed to OEM standards. Fuel pressure is an important aspect of the Delphi CFE0113's performance, as fuel pumps supply fuel to the engine's injectors.

Testing fuel pressure

Step 1: Check for Gas in the Tank

This may sound obvious, but it's a good first step to take before you rent or buy a fuel pressure tester. Even if your fuel gauge shows a full tank, it could be faulty. Add at least two gallons to the tank and try to start the engine. If it works, check the fuel gauge for internal failure and replace it if necessary.

Step 2: Verify the Fuel Pump Works

Head to the fuel tank and ask an assistant to turn the ignition switch to "On". You should be able to hear a two-second whir, hum, or series of rapid clicks as the fuel pump pressurises the fuel line to the engine. If you don't hear any noise, this means the pump is not getting power or has failed. Check the fuel pump fuse and relay. If both are good, check the wiring to the pump. If voltage is present when turned to "on", then the pump has failed and should be replaced.

Step 3: Connect a Fuel Pressure Tester

Pop the hood and find a Schrader valve fitting on the fuel rail. Remove the Schrader valve cap and attach the appropriate fuel pressure tester fitting. Ensure it threads on properly for a leakproof fit. Do not start the engine, but turn the ignition to "on". Check the psi reading and wait. If the psi drops, this indicates a leak in the system. If the fuel pressure remains the same after 5 to 10 minutes, the system is holding pressure well.

Step 4: Start the Engine

Once the engine is started, let it idle and check the psi reading again. You should see a steady fuel pressure, within a few psi of the recommended pressure. Once the engine is warmed up, slowly rev the engine and check that the pressure rises with the RPMs. If your fuel pressure holds steady, rises with engine speed, and is at the recommended pressure, then your engine problem does not seem fuel-related.

Understanding Fuel Pressure Readings

If you have zero fuel pressure, this means the pump is dead or not getting power. Check the fuel pump fuse and then verify power to the pump with a multimeter. If it's good, swap out the fuel pump.

Low fuel pressure could be caused by a clogged fuel filter or a failing pump. If it is a serviceable type filter, replace the fuel filter. It could also be caused by improper tank venting or an emissions issue caused by a loose gas cap. Check that the cap gasket isn't damaged, and tighten it until it clicks.

High fuel pressure could be caused by a clogged or kinked fuel return line, a bad fuel pump driver module, or a powertrain control module. These would likely be indicated by a "check engine" light. High fuel pressure can also be caused by a faulty fuel pressure regulator.

Testing fuel volume

A simple volume test involves opening the fuel supply line at the injector rail and measuring the volume of fuel during a timed, power-on fuel pump test. This involves pumping gasoline into an open container at a high rate, which can pose safety risks. Dedicated equipment is available to safely and conveniently test fuel pressure and volume.

The most accurate method of testing volume is to measure the flow exiting the pressure regulator with the pump activated. For most applications, the fuel pump should produce at least three pints of fuel in 30 seconds. On single-line systems, the volume can only be measured from a disconnected fuel line.

To perform a volume test, you will need to disconnect the line and direct the flow into a vessel. This will allow you to measure the volume of fuel pushed by the pump in a set amount of time.

It is important to note that a fuel pump with low volume may still maintain pressure, making this condition harder to diagnose. The symptoms of this type of failure are usually related to drivability. At idle, the engine uses a small amount of fuel and runs fine. However, when fuel consumption exceeds what the pump can provide, the pressure drops, resulting in drivability issues.

In addition to volume testing, it is crucial to test fuel pressure to ensure accurate fuel pump diagnosis. This involves measuring both regulated and unregulated fuel pressures to determine if they are up to specifications. The unregulated fuel pressure indicates how much pressure the pump will deliver while the engine is under full-load, low-manifold-vacuum conditions. Reinstalling the pressure regulator vacuum hose will return the fuel pressure to the manufacturer's idle specification.

By performing both fuel volume and pressure tests, you can comprehensively evaluate the performance of your fuel pump and identify any potential issues.

Electric vs. mechanical fuel pumps

Fuel pressure is an important aspect of a vehicle's fuel system, and the choice between an electric and a mechanical fuel pump can impact performance and maintenance requirements. Here is a detailed comparison between the two:

Functionality:

• Mechanical Fuel Pumps: These pumps are mounted on the vehicle's engine and use a lever that rides on a cam lobe or a pushrod to create suction, pulling fuel from the tank to the carburetor. They have a pre-set fuel pressure suitable for typical two and four-barrel carburetors.
• Electric Fuel Pumps: Electric pumps can be found inside the fuel tank or mounted externally. They push the fuel towards the engine and must be positioned lower than the fuel tank to prevent fuel starvation and pump burnout.

Performance:

• Mechanical Fuel Pumps: These pumps are generally quiet and do not contribute to engine noise. However, they may not provide sufficient pressure and volume for fuel injection conversions. Additionally, extended cranking periods may be required if the vehicle has been sitting for a long time, as they only pump fuel when the engine is cranking.
• Electric Fuel Pumps: Electric pumps can deliver higher pressure and are suitable for both carbureted and fuel-injected engines. They can prime the carburetor before starting, which is beneficial for vehicles that sit for extended periods. However, they may produce more operational noise, especially if mounted externally.

Maintenance and Installation:

• Mechanical Fuel Pumps: These pumps are easy to test with a vacuum and fuel pump tester and do not require a fuel return line to the tank. However, they may not be suitable for fuel injection systems without modifications.
• Electric Fuel Pumps: Electric pumps often require a regulator, especially for fuel injection systems, to control fuel pressure. They can be more challenging to install, requiring careful mounting to prevent fuel starvation. In-tank pumps are generally preferred for their quieter operation and ease of fuel supply to the pump.

Fuel Filtration:

• Mechanical Fuel Pumps: A simple inline fuel filter between the pump and carburetor is usually sufficient. A pre-filter is typically not needed due to the in-tank pickup assembly's filter sock.
• Electric Fuel Pumps: For inline electric fuel pumps, a pre-filter is necessary to protect the fine internals of the fuel injectors. A finer post-filter is also recommended to ensure ample fuel filtration.

Horsepower Considerations:

The impact of switching from a mechanical to an electric fuel pump on horsepower is minimal. While electric pumps may provide a slight increase in horsepower due to lower fuel charge heating, the overall difference is negligible. The choice between the two should be based on compatibility, performance requirements, and personal preference rather than horsepower gains.

High-pressure fuel pumps

The Delphi Gasoline Fuel Pump CFE0113 is an electric fuel pump that is installed in the fuel tank. Fuel pumps can be categorised as either regular or high-pressure. High-pressure fuel pumps are an essential component of modern direct petrol injection engines, which have a fuel system consisting of a low-pressure system with a high-pressure circuit.

In a low-pressure circuit, fuel is drawn from the tank by an electrical fuel pump and then sent to the high-pressure pump. The system pressure in the low-pressure circuit is controlled by the engine control unit and can reach up to 6.0 bar. In the high-pressure circuit, the high-pressure pump pushes fuel through high-pressure fuel lines into the fuel distribution pipe (also known as the rail), where it reaches the cylinders via electrical high-pressure injection valves. The engine control unit monitors the fuel pressure in the high-pressure circuit, adjusting it from 50 to 350 bar as needed.

The high-pressure pump's delivery rate is proportional to the engine speed since it is driven mechanically by the camshafts. The engine control unit uses a pressure sensor to monitor the fuel pressure and adjusts it via a flow control valve installed in the pump. This demand-based control ensures that only the required high pressure is generated in the pump.

Fuel pump replacement

A fuel pump is a small electric motor that transfers fuel from the fuel tank to the engine. Fuel pumps are durable but not indestructible, and they will likely need to be replaced at some point. The average price of a fuel pump is around $350, but it can range from $15 to over $2,000. If you are bringing your car to a mechanic, you will also need to account for the cost of labor.

Step 1: Park your vehicle and locate the fuel pump

Park your vehicle on a firm, level surface and engage the parking brake. The fuel pump is typically located inside the fuel tank, so you will need to open the fuel cap. Turn the key to the "on" position and listen at the filler opening. If the fuel pump is working properly, you should hear a hum for two to three seconds. If there is no sound, the pump may need to be replaced.

Step 2: Check the fuel pump fuse and relay

Find and verify the fuel pump fuse and relay. If the fuse is blown, replace it with a fuse of the same amperage and check if the fuel pump is now operational. If the fuse and relay are functional, move on to the next step.

Step 3: Check for power and ground at the fuel pump

Remove the fuel tank or the back seat to access the fuel pump. Check for power and ground at the pump. If there is power and ground, the pump is likely faulty and needs to be replaced.

Step 4: Prepare the fuel tank for removal

Relieve the fuel system pressure by disconnecting the negative battery cable. Siphon or drain as much fuel as possible from the fuel tank. Disconnect the filler tube hose and the electrical connection to the pump. Support the fuel tank with a jack and a block of wood, and remove any retaining straps or bolts holding the tank to the frame.

Step 5: Remove the old fuel pump and install the new one

Disconnect the fuel lines from the fuel pump and remove the pump from the tank. Compare the new fuel pump with the old one to ensure you have the correct part. Install the new fuel pump and connect the fuel lines to the pump.

Step 6: Reinstall the fuel tank and test the new fuel pump

Lift the fuel tank back into place and install the retaining strap. Reconnect the filler tube hose and the electrical connector. Reconnect the negative battery cable and fill the tank with gas. Conduct a road test to confirm that the new fuel pump is functioning properly.

Additional Tips:

• Work in a well-ventilated area, preferably outdoors, to minimize the risk of fire or inhalation of harmful fumes.
• Always wear safety gear, such as safety glasses, gloves, and appropriate clothing, to protect yourself from fuel spills and splashes.
• Drain the fuel tank to reduce the risk of spills and make it easier to handle.
• Clean around the fuel pump to prevent dirt and debris from falling into the fuel tank.
• Consider replacing related components such as the fuel filter, fuel pump strainer, and fuel tank O-ring or gasket.

Frequently asked questions