Changing Fuel Pressure Regulator In 2003 Duramax: Step-By-Step Guide

Changing the fuel pressure regulator on a 2003 Duramax is a complex process that requires a range of tools and mechanical expertise. The regulator is located in the valley of the engine, towards the front, and is attached to the CP3 injection pump. To access and replace the regulator, several components must be removed, including the air intake pipe, A/C compressor, water outlet pipe, electrical connections, and fuel inlet hose. Special attention must be paid to the Torx bolts holding the regulator in place, as they can be challenging to remove without stripping. The entire process can take several hours, and it is recommended to have a range of tools, including various sizes of wrenches, sockets, screwdrivers, pliers, and a breaker bar.

Disconnect the negative feed from the batteries

Disconnecting the negative feed from the batteries is the first step in changing the fuel pressure regulator in a 2003 Duramax. This is an important safety precaution as it prevents the risk of electric shock.

To begin, locate the negative battery terminal. This is usually marked with a "-" symbol or a black cover. Once you have identified the negative terminal, proceed to disconnect the feed. You may need to use a wrench or a socket to loosen the nut or bolt that secures the cable to the terminal. Make sure you have a firm grip on the cable and gently pull it away from the battery.

It is important to note that battery cables can carry a residual charge even when disconnected. To ensure your safety, wear insulated gloves and avoid touching any metal parts of the cable or battery. Place the disconnected cable in a safe location away from the battery to avoid accidental contact.

Additionally, here are some general safety tips when working with batteries:

• Keep sparks, flames, and lit cigarettes away from the battery.
• Do not allow jewellery or conductive materials to come into contact with the battery.
• Always wear protective gear, including eye protection and gloves.
• If battery acid contacts your skin, eyes, or clothing, flush it immediately with water.

By following these instructions and taking the necessary safety precautions, you can safely disconnect the negative feed from the batteries in your 2003 Duramax.

Remove the belt from the pulleys

To remove the belt from the pulleys, you will need a 1/2" breaker bar. Place the head of the bar into the square socket on the belt tensioner. Push on it towards the passenger side and then lift the belt off the AC Compressor unit with your right hand.

This process is part of Step 1: Preparation, which also includes disconnecting the negative feed from the batteries.

The tools required for the overall fuel pressure regulator replacement include:

• 8mm wrench
• 10mm wrench
• 1/4" open wrench
• Screwdriver bit extension
• T25 Screwdriver bit
• Long screwdriver
• 15mm socket
• 10mm socket
• 13mm socket
• 3/8" socket swivel adapter
• 3/8" Extension
• 1/4" Breaker-bar
• Needle-nose pliers (angled works best)
• Magnet wand
• I-dropped-a-bolt-grabber thing

Disconnect the two connectors on the AC unit

To disconnect the two connectors on the AC unit of a 2003 Duramax, follow these steps:

First, make sure you have all the necessary tools for the job. For this step, you will need a 15mm socket.

Now, locate the two connectors on the AC unit. They should be marked with a blue circle in the picture provided in the guide. Once you have found them, use the 15mm socket to remove the four bolts that mount the AC unit to the engine. These bolts are marked with white circles and arrows in the picture.

Once the bolts are removed, move the AC unit out of the way by flipping it over towards the passenger side battery.

It is important to note that this is just one step in the process of changing the fuel pressure regulator in a 2003 Duramax. There are several other steps that must be completed before and after this one, so make sure you have a complete guide and all the necessary tools before beginning the job.

Remove the red bolt from the thermostat housing

To remove the red bolt from the thermostat housing of a 2003 Duramax, you will first need to disconnect the negative feed from the batteries. Then, using a 1/2" breaker bar, remove the belt from the pulleys by placing the bar into the square socket of the belt tensioner and pushing it towards the passenger side. You can then lift the belt off the AC compressor unit.

Next, you will need to remove the air intake. There are three hose clamps to loosen. The front-most clamp is circled in the image, and once removed, you can reach to the back and pull off the "6.6 Turbo Diesel" cover. This will reveal the second clamp, and the third is by the air filter. You don't need to remove the air box, just take the big clamp off. To remove the assembly, simply twist and pull from the engine side.

Now, disconnect the two connectors on the AC unit, which are marked with blue circles in the image. Using a 15mm socket, remove the four bolts that mount the AC unit to the engine, which are marked with white circles and arrows. Move the AC unit out of the way by flipping it towards the passenger side battery.

Using a sharp object, open the clip (white circle) that holds the wire harness together. Then, remove the red bolt from the thermostat housing and set the bracket aside.

• Use a 3-inch Torx bit and a 1/4 wrench to remove the FPR screws. You can run a magnet across the tip of the bit to help hold it in place and extract the screws.
• It is not necessary to disconnect half of what is instructed; just go after the FPR and remove what is necessary.
• Be careful with the Torx screws as they can be stubborn, and you don't want to round them.

Loosen the hose clamp on the coolant pipe

To loosen the hose clamp on the coolant pipe of your 2003 Duramax, you'll need to gather the necessary tools and prepare your vehicle. Here's a step-by-step guide to help you through the process:

Step 1: Gather the Required Tools

Before you begin, ensure you have the right tools for the job. For this task, you'll need a sharp object, such as a small screwdriver or pick, to loosen the hose clamp. Having some rags or towels nearby is also a good idea to wipe up any coolant that may spill.

Step 2: Prepare the Vehicle

Park your vehicle on a level surface and engage the parking brake. Lift the hood and locate the coolant reservoir. Identify the hose clamp that secures the coolant pipe. It's usually held in place by a metal clamp or a hose clamp screw.

Step 3: Loosen the Hose Clamp

Using your sharp object, carefully insert it under the edge of the hose clamp. Gently pry it upward to loosen the clamp. You may need to work your way around the circumference of the clamp to fully loosen it. Be cautious not to damage the hose or any nearby components.

Step 4: Release the Coolant Pipe

Once the hose clamp is loose, you can now release the coolant pipe. Gently pull the pipe away from the connection. Have your rags or towels ready to catch any coolant that may spill. It's a good idea to have a container nearby to collect any spilled coolant.

Step 5: Prepare for Reinstallation

If you're replacing the coolant pipe or hose, ensure you have the new parts ready. Clean the connection point and inspect it for any debris or damage. Refer to your vehicle's repair manual or a trusted online source for specific instructions on reinstalling the coolant pipe or hose for your 2003 Duramax.

Step 6: Reinstall the Coolant Pipe

Carefully reposition the coolant pipe or hose back into place. Secure it firmly with the hose clamp. Ensure the clamp is tight enough to prevent leaks but not too tight as to damage the hose.

Step 7: Refill and Bleed the Cooling System

After reinstalling the coolant pipe, refill the coolant reservoir with the appropriate coolant for your vehicle. Start the engine and let it run for a few minutes. Check for any leaks around the hose connection. If no leaks are present, bleed the cooling system by following the procedure outlined in your vehicle's repair manual.

Remember to dispose of any spilled coolant properly and according to local regulations. Coolant is toxic to humans, pets, and the environment, so take the necessary precautions when handling it.

Frequently asked questions