1970-1979 MG Midget Fuel Pump Cut-Off Switch Guide
Understand the function, failure symptoms, and replacement of your classic Midget's fuel pump inertia switch.
- The fuel pump cut-off switch is a safety device that stops fuel flow in a crash to prevent fire.
- A 'no-start' condition where the engine cranks but won't fire is the most common symptom of a tripped or failed switch.
- You can temporarily bypass the switch with a jumper wire for testing, but it should not be left bypassed permanently.
- For a vehicle of this age, a new aftermarket switch is a more reliable choice than a used original part.
Symptoms of a Failing Fuel Pump Cut-Off Switch
A faulty inertia switch can mimic other fuel system problems. The most common signs point to a lack of fuel reaching the engine.
- Engine Will Not Start: The engine will crank over but will not fire up because the fuel pump is not receiving power. 🎬 Watch how to check the switch before replacing your fuel pump. This is the most definite symptom of a tripped or failed switch.
- Engine Stalls Suddenly: The switch might fail or be tripped by a large pothole or jolt, causing the engine to shut off while you are driving.
- Intermittent Power to Fuel Pump: A switch that is failing internally can cause the fuel pump to work only sometimes, leading to unpredictable stalling or no-start conditions.
Choosing the Right Aftermarket Switch
For a classic vehicle like the MG Midget, finding original equipment (OEM) parts can be difficult. Aftermarket parts are the most common and accessible solution.
Standard Ignition is a known brand in the aftermarket world. While specific reviews for their inertia switches on an MG Midget are not readily available, the brand generally produces reliable replacement components for a wide range of vehicles. Given that the inertia switch is a relatively simple mechanical and electrical device, a new aftermarket part from a reputable manufacturer is often a more reliable choice than a used, decades-old original part which may have unseen wear or corrosion.
Some owners of classic British cars choose to retrofit inertia switches for safety if their car did not originally have one. 🎬 See how to retrofit an inertia switch for added safety. When replacing a failed switch, using a new aftermarket part ensures the component will function as designed in an emergency.
Cost of Replacement Fuel Pump Cut-Off Switch (1970-1979 MG Midget)
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket (Standard Ignition) | $102.21 |
| Used OEM | $20 - $50 (Varies by seller and condition) |
| Shop Labor | $60 - $120 |
Frequently Asked Questions
Where is the fuel pump cut-off switch located on a 1970-1979 MG Midget?
On later model Midgets and other MG vehicles, the inertia switch is typically found mounted inside the car. Common locations include behind a kick panel in the passenger or driver's footwell, or in the trunk area. It is often identifiable by a red reset button accessible through a hole in a trim panel.
How do I reset the fuel pump cut-off switch?
If the switch has been tripped, you can reset it manually. First, turn the ignition off and inspect the vehicle for any fuel leaks. If there are no leaks, locate the switch and press the reset button, which is usually on top of the device. 🎬 Follow this quick guide to resetting your fuel shutoff switch. After resetting, turn the key to the 'on' position for a few seconds to allow the pump to prime before starting the engine.
Can I bypass the fuel pump cut-off switch?
You can temporarily bypass the switch for diagnostic purposes by connecting the two wires of the electrical connector together with a jumper wire. However, this is not recommended as a permanent solution. Bypassing the switch eliminates a critical safety feature designed to prevent fires in an accident.
How can I test if my inertia switch is bad?
If your engine won't start, you can test the switch by bypassing it with a jumper wire. Unplug the electrical connector from the switch and use a small wire to connect the two terminals in the plug. If the car starts and runs with the jumper in place, the inertia switch is faulty and needs to be replaced.
Helpful Videos
Technical Specifications
A safety switch sensitive to sudden impact or rollover that interrupts the 12-volt power supply to the electric fuel pump.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.