Replacing Fuel Pump In '87 Toyota Dolphin Motorhome: Step-By-Step Guide

If you're looking to replace the fuel pump on your 1987 Toyota Dolphin Motorhome, you've come to the right place. This step-by-step guide will walk you through the process of replacing the fuel pump and getting your motorhome back on the road. Before you begin, it's important to note that fuel pumps for the engine on almost all vehicles are located inside the gas tank, and accessing them typically requires removing the tank. Now, let's get started!

Fuel pump relay may be stuck closed

If your fuel pump relay is stuck closed, it means that the fuel pump will run continuously. This is a rare occurrence but can happen when the circuit is supplying power to the fuel pump fuse at all times. You will hear the fuel pump running continuously, even when the key is out of the ignition.

To fix this, you will need to replace the fuel pump relay. The part itself costs less than $20. You can also try to temporarily swap it with another (unimportant) relay from the power distribution box. For example, you might swap the fuel pump relay with the air conditioning compressor relay if they share the same design. If the fuel pump runs with the alternate relay installed, you know the fuel pump relay needs to be replaced.

The fuel pump relay is typically located in the power distribution box in the engine compartment. You can consult your owner’s manual for help finding the relay.

In addition, you should also look for a possible bypass circuit installed to run the fuel pump all the time. If you bought the car with the problem, someone may have installed a bypass.

Check for a bypass circuit

To check for a bypass circuit, you must first understand what a bypass circuit is and what it does. A bypass circuit is an additional circuit installed in a vehicle's electrical system that allows the fuel pump to run continuously, bypassing the regular relay or control system. This means that the fuel pump will be active even when the vehicle's ignition is turned off.

Now, to check for the presence of a bypass circuit in your 1987 Toyota Dolphin motorhome, you should inspect the vehicle's fuel pump wiring and electrical system. Here are the steps you can follow:

• Locate the fuel pump: The fuel pump in your 1987 Toyota Dolphin motorhome is most likely located inside the fuel tank, as this is common for many Toyota vehicles of that era. You may need to remove the fuel tank to access it.
• Inspect the fuel pump wiring: Once you have located the fuel pump, carefully examine the wiring connected to it. Look for any signs of tampering, modifications, or additional wiring that does not appear to be part of the factory setup.
• Identify the fuel pump relay: The fuel pump relay is responsible for controlling the power supply to the fuel pump. It is usually located in the engine bay, often near the fuse box or the battery. Identify the relay and inspect its wiring as well.
• Consult factory manuals or diagrams: To better understand the fuel pump circuit, consult factory service manuals or electrical diagrams specific to your 1987 Toyota Dolphin motorhome. This will help you identify any components or wiring that do not belong or deviate from the standard configuration.
• Compare with a similar vehicle: If possible, find another 1987 Toyota Dolphin motorhome with a known untouched fuel pump circuit. Compare the wiring and electrical components between the two vehicles to spot any differences or modifications.
• Seek professional assistance: If you are unsure or unable to locate the bypass circuit, consider seeking the help of a qualified mechanic or auto electrician. They will have the expertise and tools to diagnose and identify any modifications made to the fuel pump circuit.

Remember, a bypass circuit can impact the normal operation of the fuel pump and may be a potential safety hazard. If you discover the presence of a bypass circuit, it is recommended to have it properly diagnosed and rectified by a professional.

Disconnect fuel lines to the fuel pump

Disconnecting the fuel lines to the fuel pump is a crucial step in changing the fuel pump on your 1987 Toyota Dolphin motorhome. Here is a detailed guide to help you through the process:

Before beginning any work on your vehicle, it is important to ensure your safety. Make sure the engine is turned off and cooled down, and engage the parking brake to prevent any accidental movement. Place wheel chocks around the tyres for added safety. Wear protective gear, including gloves and eye protection, to shield yourself from any fuel spillage or debris.

Now, locate the fuel pump. In your 1987 Toyota Dolphin, the fuel pump is likely located on the right rear of the cylinder head. Once you have identified the fuel pump, proceed to locate the fuel lines connected to it. There should be three hoses attached to the fuel pump.

Place a container or rag underneath the fuel lines to catch any spilled fuel. Using the appropriate tools, carefully loosen and detach the fuel lines from the fuel pump. Be cautious as you work to avoid any damage to the fuel lines, as they are essential for the proper functioning of your vehicle.

Once the fuel lines are disconnected, gently move them away from the fuel pump to prevent fuel leakage. Ensure that the fuel lines are securely clamped or tied to prevent them from accidentally falling back onto the fuel pump. You may also consider using zip ties or clamps to secure the fuel lines in a safe position.

At this point, the fuel pump should be free from the fuel lines. You can now proceed to the next step of removing the bolts that attach the fuel pump to the cylinder head. Remember to keep the detached fuel lines safely away from the pump to avoid any accidental reconnection.

By following these steps, you will have successfully disconnected the fuel lines from the fuel pump on your 1987 Toyota Dolphin motorhome, allowing you to proceed with the fuel pump replacement process. Always refer to the vehicle's manual or seek advice from a certified mechanic if you have any doubts or concerns during the procedure.

Remove bolts attaching pump to cylinder head

To remove the bolts attaching the pump to the cylinder head of your 87 Toyota Dolphin motorhome, you'll need to locate the fuel pump first. In your vehicle, the fuel pump is located on the right rear of the cylinder head.

Once you've located the fuel pump, follow these steps to remove the bolts attaching it to the cylinder head:

• Disconnect the fuel lines running to the fuel pump. This will involve carefully detaching the fuel hoses or pipes that supply fuel to the pump from the fuel tank. Make sure to prepare some rags or a container to catch any spilled fuel.
• Now that the fuel lines are disconnected, you can focus on removing the bolts. Identify the bolts that secure the fuel pump to the cylinder head. These bolts will likely be located around the perimeter of the pump's mounting flange or bracket.
• Using the appropriate size socket or wrench, loosen and remove these bolts one by one. Place them in a safe place so you can reuse them during the installation of the new fuel pump.
• With all the bolts removed, you should now be able to carefully lift or wiggle the fuel pump free from the cylinder head. It may be a tight fit, so take your time and work it loose gently to avoid damaging any surrounding components.

Remember to clean the mating surfaces of the cylinder head and pump, and install a new gasket during the installation of the new fuel pump.

Clean mating surfaces of old gasket material

To clean the mating surfaces of old gasket material, you'll want to use a variety of tools to get the job done properly. Firstly, it is important to protect your eyes and ears when using any type of power equipment. Seal off open passages using masking tape, paper towels, or rags to prevent dirt, carbon, old gasket material, and other debris from entering important engine areas.

There are a variety of metal and plastic scrapers that can help remove old gasket material. Flat-blade paint removal-type scrapers are the most popular, along with carbide scrapers. A razor blade (metal or plastic) mounted in a holder can also be useful for removing MLS coating from sealing surfaces. When using a scraper or razor blade, maintain a flat, low angle to the surface to avoid creating gouges, and avoid using the corners of the blade. For cleaning aluminium surfaces, be sure to use a plastic scraper or plastic razor blade.

A coarse wire wheel (0.014" wire) can be used on cast iron sealing surfaces, but not on aluminium or plastic surfaces. A fine wire wheel (0.006" wire) can be used on both cast iron and aluminium surfaces. Use caution and "feel" when operating a wire wheel in a die grinder to preserve the surface finish of the sealing surface.

A brass hand wire brush, or nylon or brass rifle-type or round brushes, can be used to clean RTV from aluminium and plastic valve covers and intake manifolds. These brushes are also useful for cleaning out bolt holes.

When choosing a cleaner or degreaser, select one that doesn't leave any residue or oily finish. Be sure to wear proper protection on your hands and eyes, and use a rag that leaves little to no lint behind. If possible, rinse off engine parts with water and blow them dry.

Small pocket screwdrivers and dental-type picks with straight and curved tips are handy for removing O-rings, RTV in crevices, and dirt/crud caught in small areas.

Frequently asked questions