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Written By: Gibson Hull
April 05, 2025
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Internal combustion engines just need three inputs to run: fuel, air, and spark. Air is easy to check: is the intake covered, or constricted? Even easier on this FJ40 because it is carbureted. No need to worry about a cranky air sensor used on the computer controlled engines of today. I like to check fuel before spark because it is the next easiest step. Is there any gas in the tank? I've wasted hours trying to get an engine to run only to realize there is no gas in the tank… Then it is a simple process of elimination from the carburetor where the fuel comes into the engine, back to the fuel tank where the fuel waits to be burned. There are just fuel lines and a simple mechanical fuel pump between engine and tank on the FJ40, but this process of elimination works on every internal combustion engine.
None of the fuel lines were leaking and we had gas in the tank. But, the carb was not getting any gas and the FJ40 had not been sitting very long. The clear culprit at this point was the fuel pump.
The fuel pump’s arm is operated by the engine’s camshaft as it turns, moving the diaphragm in the pump back and forth and creating pressure. It sucks fuel from the tank and pumps it up to the carburetor. Fuel pumps typically fail when the synthetic diaphragm in the pump wears out.
Fig. 1: Here comes the cavalry.
Fig. 2: The stationary FJ.
Step 02: Remove and inspect fuel lines. (Not pictured). This FJ’s fuel lines were in great shape, further confirmation we were not losing fuel here. Simply remove the hose clamps with a screw driver, socket, or wrench of choice. Then gently but firmly pull the fuel lines from the fuel pump, careful to catch any escaping fuel.
Step 03: Remove mounting bolts. Simply unscrew the two bolts holding the fuel pump to the engine. They may be stubborn due to sealant around the fuel pump spacer and gaskets.
Step 04: Remove fuel pump from engine. There may be sealant holding the fuel pump to the engine. Simply pull it free, but be careful not to damage any internal engine components with the pump’s arm.
Step 05: Clean mating surface. (Not pictured). Clean around the holes for the fuel pump and bolts. Be careful not to allow any debris into the engine.
Step 01: Locate fuel pump.
Step 03: Remove mounting bolts.
Step 04: Remove fuel pump from engine.
Step 07: Install new fuel pump. Gently place the fuel pump with a new spacer and gaskets back in place. You can add a very thin skim of silicone sealant between the pump, gaskets, spacer, and engine to ensure a complete seal.
Step 08: Reinstall fuel lines. (Not pictured). Replace the fuel lines back to the same ports as before on the new fuel pump and tighten all hose clamps.
Step 09: Jump start dead battery. The FJ40’s battery was flat, Helio to the rescue!
Step 10: Start FJ40 and check for leaks. After a few cranks the fuel pump pulled fuel from the tank and pushed it into the carb, and the FJ40 roared back to life!
Step 06: Inspect old pump.
Step 07: Install new fuel pump.
Step 09: Jump start dead battery.
Step 10: Start FJ40 and check for leaks.