Rick's Free Auto Repair Advice

Where is the fuel pump cutoff switch?

How to reset a fuel pump cutoff switch?

Ford Motor Company has used a fuel pump cutoff switch,

fuel cutoff switch

Early Ford inertial fuel cutoff switch

also called an inertial fuel cutoff switch since the introduction of fuel injection and gas tank mounted fuel pumps. The reasoning behind the fuel pump cutoff switch is that, in the event of a collision, it’s possible for the electric fuel pump to continue pumping fuel to the engine compartment even if the engine has stalled. Ford felt that this created an unreasonable risk of fire after a collision.

What is a fuel pump cutoff switch?

The early switches contained a gold plated steel ball that’s held in place by a magnet. While held by the magnet, the ball touched electrical fuel pump cutoff switchcontacts and maintained power to the fuel pump. However, when the vehicle encountered an impact strong enough to move the ball away from the magnet, the ball would move off the magnet, disrupting electrical flow to the pump.

What would make the fuel cutoff switch stop fuel?

The early inertial fuel cutoff switches could activate simply by bumping the vehicles. This happened quite often in parking lots if another vehicle as much as touched your car while maneuvering. You would return to your car and try to start it, not knowing that it had been bumped. The engine would crank but would not fire up because it had no fuel.

Unfortunately, the older switches could also activate on intertial fuel cutoff switchrough roads or when hitting a deep pothole. Simply put, they were not very accurate in detecting the difference between an impact and a bump.

How do you reset a fuel pump cutoff switch?

Most Ford fuel cutoff switches incorporate a manual reset button that moves the steel ball back into place against the magnet, thus resetting the system. Unfortunately, Ford moved the position of the inertial fuel cutoff switch to several locations over the years. The switch was located in the trunk in early designs, making it the safety factor for rear end collisions. In later years, Ford moved the switch to either the right or left kick panels in the passenger compartment. Once you find the inertial fuel cutoff switch, resetting is as simple as pushing the red reset button.

Why did Ford stop using the inertial fuel cutoff switch?

Just because you can’t find the switch doesn’t mean Ford stopped using it. They still employ an inertial fuel cutoff switch, only now it’s incorporated into the supplemental restraint system. This makes far more sense since the SRS is designed to activate the seat belt tensioning system and airbags when a vehicle impact force reaches a set level.

Why don’t other car makers use an inertial fuel pump cutoff switch?

Other car makers use different safety strategies to shut off the fuel pump. GM and many others uses the oil pressure switch. If the engine is damaged and not running, the sudden drop in oil pressure will stop electrical flow to the fuel pump

©, 2017 Rick Muscoplat




Posted on by Rick Muscoplat

Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN