Installing A Fuel Pressure Gauge On Your 95 Cummins

Installing a fuel pressure gauge on a 95 Cummins involves several steps and additional parts. The process includes tapping into the fuel system, typically by replacing a banjo bolt with a tapped banjo bolt, and then attaching a grease gun flex hose, a needle valve, and a sender unit. The sender unit is then secured to the fender apron. It is recommended to get the fuel pressure reading after the fuel filter, rather than straight from the pump, to accurately monitor the fuel pressure and make informed decisions about fuel filter changes. Some users also suggest including a snubber valve or a ball valve in the line to regulate fuel pressure spikes and prevent potential damage to the electronic sensor. The length of the tubing between the tap point and the sensor can impact the accuracy of the readings, with longer tubing helping to dampen pressure pulses.

Tapping the banjo bolt

Step 1: Remove the Factory Banjo Bolt

Locate the banjo bolt on the fuel filter housing. This is usually the banjo bolt with the bleeder valve, which is used to bleed the system when changing the fuel filter. Use an appropriate-sized wrench to remove the factory banjo bolt. Also, remove the crush washers from both sides of the fuel line.

Step 2: Install the Tapped Banjo Bolt

Thread the tapped banjo bolt into the fuel filter housing. Ensure that you use a new crush washer on each side of the banjo bolt for a secure seal. Torque the banjo bolt to the specified value, typically around 18 foot-pounds, using a torque wrench.

Step 3: Connect the Fuel Pressure Sensor

Now, you can connect the fuel pressure sensor to the tapped banjo bolt. You may need to use a snubber valve or a needle valve between the banjo bolt and the sensor to dampen pressure pulses and provide accurate readings. Follow the instructions provided with your fuel pressure gauge kit for the correct installation procedure.

It is important to note that there are different sizes of banjo bolts used on Cummins engines. For the 95 Cummins, you will typically need an M12 x 1.5 banjo bolt. However, it is always a good idea to verify the size before proceeding with the installation. Additionally, some fuel pressure gauge kits may provide pre-tapped banjo bolts specifically designed for your Cummins engine, which can simplify the installation process.

By following these steps and ensuring you have the correct parts, you can successfully tap the banjo bolt and install your fuel pressure gauge on your 95 Cummins.

Installing a needle valve

To install a needle valve as part of your fuel pressure gauge setup, you will first need to source a needle valve. Some Cummins forum users suggest that any old needle valve will do, while others recommend specific products, such as the Tork Tek Cummins Banjo Snubber, which has a built-in restrictor to dampen pressure spikes.

You will also need to source a tapped banjo bolt, which can be purchased from vendors listed on the Cummins forum or drilled and threaded yourself. This will replace the factory bolt on the fuel filter housing. The tapped banjo bolt will allow you to attach the needle valve to the fuel filter housing.

Once you have your parts, the installation process is as follows:

• Replace the factory bolt on the fuel filter housing with the tapped banjo bolt.
• Attach the needle valve to the tapped banjo bolt.
• Connect the sending unit to the other side of the needle valve.
• Mount the sending unit on the fender apron.

Some users also recommend adding a snubber and/or a length of tubing between the tapped banjo bolt and the needle valve to further dampen pressure spikes and reduce the chance of damaging your fuel pressure gauge.

It is important to note that the needle valve should only be slightly opened when the engine is running, to prevent damage to the gauge.

Using a snubber

A pressure gauge snubber is a fitting attached to a pressure gauge to even out pressure fluctuations. It does not alter the process pressure but reduces pulsations on the line, improving the accuracy of gauge readings and extending the life of the gauge.

In the context of installing a fuel pressure gauge on a 95 Cummins, a snubber can be used to prevent fuel pressure spikes from damaging the electronic fuel pressure sensor. It is not strictly necessary, but it does offer protection in case of sudden pressure spikes.

Step 1: Prepare the Fuel Pressure Sensor and Snubber Valve

• Wrap the male threads of the fuel pressure sensor with Teflon tape to ensure a tight seal.
• Screw the fuel pressure sensor into the female end of the snubber valve.

Step 2: Select the Installation Location

Choose an appropriate location to install the snubber valve. The recommended location is between the banjo bolt on the fuel filter housing and the fuel pressure sensor. Alternatively, you can install it directly into the aftermarket fuel pump's test port.

Step 3: Prime the Fuel System

Refer to the manufacturer's guidelines to prime your Cummins' fuel system accordingly.

Step 4: Install the Snubber Valve and Sensor Assembly

Install the snubber valve and fuel pressure sensor assembly into the selected location. Ensure that the threads of the snubber valve match the thread diameters of the pressurized line and the pressure gauge.

By following these steps, you can successfully install a fuel pressure gauge using a snubber on your 95 Cummins. The snubber valve will help protect your fuel pressure sensor from potential damage caused by pressure spikes in the fuel system.

Choosing the right tubing

When installing a fuel pressure gauge on a 95 Cummins, choosing the right tubing is crucial for accurate readings and a leak-free connection. Here are some factors to consider when selecting the appropriate tubing:

Material

The tubing material is an important consideration. While nylon tubing is commonly used for mechanical pressure gauges, it is not suitable for fuel pressure gauges. Instead, opt for tubing made from materials that are compatible with diesel fuel, such as copper or stainless steel. Braided stainless steel tubing, for example, offers durability and resistance to kinking.

Diameter and Length

Ensure that the tubing has a diameter of 1/8 inch, which is the standard size for most fuel pressure gauge fittings. As for the length, consider the distance between the gauge and the fuel system. Choose a tubing length that provides enough flexibility for routing and allows for potential adjustments. Typically, tubing ranging from 6 to 12 feet in length should be sufficient.

Wall Thickness

Consider the wall thickness of the tubing, which is typically measured in inches or millimetres. Thicker walls can provide greater durability and resistance to damage. However, ensure that the wall thickness does not restrict the flow or affect the accuracy of the fuel pressure gauge.

Ease of Installation and Leak-Free Connections

Look for tubing that is designed for ease of installation and leak-free connections. This may include tubing kits that come with ferrules, fittings, or adapters specifically designed for fuel pressure gauges. Proper fittings will ensure a secure connection between the tubing and the gauge, preventing fuel leaks.

Compatibility with Gauge and Fittings

Ensure that the tubing is compatible with your fuel pressure gauge and the fittings you intend to use. Some gauges and fittings may require specific tubing materials or diameters. Refer to the manufacturer's instructions or recommendations for your fuel pressure gauge to select the appropriate tubing.

Quality and Durability

Invest in high-quality tubing to ensure durability and leak-free performance. Read reviews and look for tubing that is known for its quality and ease of installation. Choosing a reputable brand or a tubing kit specifically designed for fuel pressure gauges can enhance the overall reliability of your installation.

Sensor placement

When installing a fuel pressure gauge on a 95 Cummins, sensor placement is crucial for accurate readings and the longevity of the sensor. The sensor should be placed after the fuel filter, as this will provide more accurate data on the fuel pressure that the injection pump is receiving. This location also helps with maintenance, as you can save money on fuel filters by only changing them when the pressure drops below the minimum requirement.

The sensor should be placed at least 12 inches away from the injection pump, with some recommending a distance of 5 feet or more. This distance helps to dampen the water hammer pulses and protect the sensor from potential damage. To further reduce the impact of these pulses, a snubber and/or a needle valve can be installed before the sensor. The needle valve should be placed about 10 inches before the injection pump, and the snubber can be placed at the tap point.

When installing the sensor, it is recommended to use 1/8" air brake tubing, as it is rated for high pressure and can withstand the conditions under the hood. The tubing should be connected to the sensor using a female 1/8" compression fitting. Make sure that all fittings are secure and tight to prevent any leaks.

It is also important to note that some sensors may require additional programming to set warning lights and trigger points for the fuel pressure readings.

Frequently asked questions