1970-1972 Audi Super 90 Fuel Pump Cut-Off Switch Explained
Address no-start or stalling conditions by understanding this key safety component in your classic Audi.
- The primary symptom of a faulty or tripped fuel pump cut-off switch is an engine that cranks but will not start due to lack of fuel.
- This part is a safety device; if it has tripped, always inspect for fuel leaks before resetting it.
- Original parts are no longer made; the only replacement option is an aftermarket part from a brand like Standard Ignition.
- There are no known recalls or common failure patterns for this specific switch on the 1970-1972 Audi Super 90.
Understanding the Fuel Pump Cut-Off Switch
On a classic car like the 1970-1972 Audi Super 90, the fuel system is relatively simple compared to modern vehicles. This model uses a carburetor, but it still relies on an electric fuel pump to move gasoline from the tank to the engine. The fuel pump cut-off switch is wired into that circuit. Under normal conditions, the switch allows electricity to flow to the pump. In the event of a sudden impact, an internal mechanism trips the switch, breaking the circuit and stopping the fuel pump instantly.
Symptoms of a Tripped or Faulty Switch
Because specific issues for the Super 90 are not well-documented, symptoms are based on the general function of this type of switch. The most common signs point to a lack of fuel delivery.
- Engine Cranks, But Won't Start: This is the most likely symptom. The starter will turn the engine over, but because the fuel pump isn't running, the engine won't get any gasoline to fire up. Many owners might mistakenly suspect a bad fuel pump when it's just a tripped or failed switch.
- Sudden Engine Stalling: A hard jolt from a large pothole or curb could potentially trip the switch, causing the engine to stall abruptly while driving because its fuel supply has been cut. A faulty switch with an internal short could also cause intermittent stalling.
Is It a Bad Switch or Something Else?
The Audi Super 90 is also known to have age-related issues like hard starting from carburetor problems or vapor lock, especially when the engine is hot. It's important to distinguish these issues from a fuel cut-off problem. If the car won't start, listen for the fuel pump; if you normally hear a faint hum when you turn the key and now you don't, the cut-off switch is a possible culprit.
Choosing the Right Aftermarket Part
Original equipment (OEM) parts for a vehicle of this age are effectively discontinued. Your only option is a new aftermarket part.
- Standard Ignition: This is the primary brand available for the 1970-1972 Audi Super 90. Standard Ignition is a well-known aftermarket manufacturer that positions its products as solutions designed to fix inherent issues with original equipment. For classic cars where OEM is not an option, a reputable aftermarket brand is a reliable choice.
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket (Standard Ignition) | $102.21 |
| New OEM | Discontinued |
| Shop Labor | $100 - $200 |
Cost estimates are based on the provided part price and national labor rate averages. Actual costs may vary.
Frequently Asked Questions (FAQ)
Are there any recalls or TSBs for the Super 90 fuel pump cut-off switch?
No. Searches of the NHTSA database and other records show no recalls or Technical Service Bulletins (TSBs) related to this specific part for the 1970-1972 Audi Super 90. Records for vehicles this old are often incomplete.
Where is the fuel pump cut-off switch located?
The exact location on a Super 90 is not documented in available resources. However, on cars from this era, these switches are commonly found in the passenger footwell area, sometimes behind a kick panel, or in the trunk near the fuel tank. You may need to consult a factory service manual for your specific vehicle to find its precise location.
Can I just reset the switch?
Yes, if the switch was simply tripped by a jolt. Most of these switches have a reset button on the top. Before resetting, it is critical to inspect for any fuel leaks. If you smell gasoline or see a leak, do not reset the switch or attempt to start the car. If there are no leaks, pressing the button should restore power to the fuel pump.
How difficult is it to replace this switch?
For a DIYer with basic tools, replacing the switch is generally straightforward once it's located. It typically involves unplugging an electrical connector and unbolting the switch from its bracket. The main challenge is often just accessing the part.
Technical Specifications
The available aftermarket part is the Standard Ignition FV-7. It features a 3-blade male terminal in an oval-shaped female connector.
We Have This Part in Stock
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.