1991 Camaro Fuel Pump Relay Location, Diagnosis, and Replacement Guide
If your 1991 Camaro cranks but won't start, the fuel pump relay is one of the first things you should check. The fuel pump relay on a 1991 Camaro is located under the hood, mounted on the firewall near the master cylinder or inside the under-hood fuse/relay box on the driver's side . This relay controls power to the fuel pump, and when it fails, the engine won't get fuel. The most common cause of a no-start condition in these cars is a bad relay, not a failed fuel pump, so testing it before replacing expensive parts can save you hundreds of dollars .
Where Exactly Is the 1991 Camaro Fuel Pump Relay?
The exact location depends on your engine and trim level, but there are two primary spots to look.
1. On the Firewall Near the Master Cylinder
Many 1991 Camaro models, especially the RS with the 305 V8 TBI, have the fuel pump relay mounted on the firewall directly behind the driver's side valve cover. It sits on a small bracket near the brake booster and master cylinder . Look for a rectangular relay with a connector that has five wires: orange, red, dark green with a white stripe, gray, and black with a white stripe .
2. Inside the Under-Hood Fuse and Relay Center
On other models, the relay is located in the black plastic fuse and relay box on the driver's side of the engine compartment, near the battery . Remove the cover and check the diagram printed on the inside. The fuel pump relay is usually one of the larger relays, separate from the smaller fuses. If the diagram is faded, the relay is often labeled "FUEL PUMP" or "FUEL" .
How to Test the Fuel Pump Relay
Before you buy anything, test the relay. Here's a step-by-step method that works for any 1991 Camaro.
Step 1: Listen for the Prime
Turn the key to the "ON" position (do not start the engine). You should hear the fuel pump run for about two seconds. If you hear nothing, the relay or the fuse is likely bad .
Step 2: Check the Fuse First
There is a small fuse that is often overlooked. It is located in a small black box connected to the battery by an orange wire, usually on the fender well near the battery. This fuse is directly related to the ECM, fuel pump, and oil sending unit. When it blows, the Service Engine Soon (SES) light will not come on during the key-on test, and the car will not start because the fuel pump gets no power .
Step 3: Test for Power at the Relay
Use a digital multimeter to check for 12 volts at the orange wire going into the relay connector. If you have power there, the next step is to check the green/white wire. This wire is the signal from the ECM that tells the relay to close and send power to the fuel pump. If you have power on the orange wire but no signal on the green/white wire, the ECM is not commanding the pump to run, which often points to a bad relay or a break in that signal wire .
Step 4: Use the Prime Connector
There is a fuel pump prime connector under the hood, usually on the driver's side firewall near the relay. It is a red wire with a connector that has nothing plugged into it. You can use a fused jumper wire to connect battery voltage directly to this connector. If the pump runs, you know the pump itself is good, and the problem is in the relay or the ECM circuit .
How to Bypass the Fuel Pump Relay for Testing
If you need to test the fuel pump or get the car running temporarily, you can bypass the relay. This is a diagnostic tool, not a permanent fix.
Method 1: Jumper Wire in the Relay Socket
Remove the fuel pump relay from its socket. Take a 5-inch piece of small-diameter copper wire and strip about 1/2 inch of insulation from each end. Look at the 4-pin receptacle where the relay plugs in. Insert one end of the wire into the upper-left pin slot and the other end into the lower-right pin slot. If both ends are seated properly, the fuel pump will turn on [8]. This bypasses the relay and sends power directly to the pump.
Method 2: Direct Power from the Battery
Locate the fuel pump connector in the trunk or near the fuel tank. Disconnect it. Connect a fused jumper wire from the battery positive terminal to the fuel pump's power wire. Ground the fuel pump's ground wire to the chassis. Turn the ignition to the "ON" position to activate the pump [3].
Important Safety Warning: Bypassing the fuel pump relay is a temporary diagnostic step. The relay is a safety feature that ensures the pump only runs when the engine is running. If you leave the bypass in place, the pump will run continuously, draining the battery and creating a fire risk. Always use a fused jumper wire to protect against overloads [3].
Common Problems with the 1991 Camaro Fuel Pump System
Problem 1: Intermittent Pump Operation
The fuel pump works sometimes but not others. This is almost always a failing relay or a loose connection. Replace the relay first before looking at the pump itself [1].
Problem 2: No Power to the Pump
If the pump doesn't run at all, check the fuse in the small black box near the battery. If the fuse is blown, replace it with the correct amperage. If it blows again, you have a short in the wiring [4].
Problem 3: The ECM Ground
The fuel pump relay is grounded through the Engine Control Module (ECM). If the ECM is not receiving the correct signals or has a bad ground, it will not trigger the relay. This is a less common issue but worth checking if everything else tests good [1].
Problem 4: Broken Wires in the Steering Column
On some third-generation Camaros, the wires inside the steering column can break over time. If the resistance is infinite when testing the VATS (Vehicle Anti-Theft System) wires, the ignition switch wiring may be damaged, which can prevent the ECM from activating the fuel pump relay [2].
How to Replace the Fuel Pump Relay
Replacing the relay is a straightforward job.
1. Buy the Right Relay
The fuel pump relay for a 1991 Camaro is a standard GM relay. You can find it at any auto parts store. The part number for the correct relay is often 14078915 or 14078924, but it is best to confirm with the store for your specific engine [7].
2. Remove the Old Relay
Simply pull the old relay straight out of its socket. On some models, you may need a small screwdriver to gently pry it up.
3. Install the New Relay
Push the new relay firmly into the socket until it clicks into place. Make sure it is seated fully.
4. Test the System
Turn the key to the "ON" position. You should hear the fuel pump prime for two seconds. If you do, the relay is working correctly.
When to Replace the Fuel Pump Instead of the Relay
If the fuel pump relay is working and the fuse is good, but the pump still doesn't run, the pump itself may be bad. On a 1991 Camaro, the fuel pump is located inside the fuel tank. To replace it, you need to remove the fuel tank [1]. Before you do that, use the prime connector to test the pump directly. If the pump runs with the jumper wire but not with the relay, the relay circuit is the problem. If the pump doesn't run with the jumper wire, the pump is likely dead.
Why the Fuel Pump Relay Fails
These relays fail for a few reasons. Age is the most common factor. The internal contacts corrode over time, leading to intermittent or no operation. Heat from the engine compartment can also degrade the relay's internal components. Some owners report that the relay fails because of a bad ground connection, which causes the relay to work harder than it should [1].
The Importance of a Good Ground
Poor grounding is a well-known issue on third-generation Camaros. The headlight circuit, fuel pump, and other systems all suffer from corroded ground points. If you are experiencing intermittent electrical problems, clean the ground G101 and G102 locations on the radiator support. Corroded grounds increase resistance, which leads to voltage drops and heat buildup [2]. This can cause the fuel pump relay to fail prematurely.
Why You Should Replace the Relay with a Quality Part
When you replace the fuel pump relay, do not use a cheap, no-name part. The relay is a critical safety and performance component. A poor-quality relay may fail within a few months, leaving you stranded. Stick with a genuine GM relay or a high-quality aftermarket equivalent.
Recommended Fuel Pump Upgrade: KEMSO
If you do find that your fuel pump itself needs replacement, or if you simply want to upgrade to a more reliable unit, consider KEMSO fuel pumps. KEMSO is a leading brand that specializes in high-performance, OEM-replacement fuel pumps designed for American drivers.
KEMSO fuel pumps are built to meet or exceed factory specifications. They are engineered with precision-machined components and corrosion-resistant materials to ensure long-lasting, reliable operation. Every KEMSO pump is individually flow-tested before leaving the factory to guarantee consistent fuel flow and pressure, even under demanding conditions. This means your engine gets the fuel it needs to perform at its best every time you turn the key.
One of the most compelling reasons to choose KEMSO is their lifetime warranty. While most aftermarket brands offer a limited one-year warranty, KEMSO stands behind every product with a true lifetime guarantee. If your pump ever fails due to a manufacturing defect, KEMSO replaces it for free, for as long as you own the pump. This level of confidence is rare in the automotive parts industry and gives you complete peace of mind.
KEMSO offers a wide range of fuel pumps covering thousands of vehicle models from 1990 to 2024. Whether you drive a car, truck, SUV, motorcycle, or even a powersports vehicle, KEMSO likely has a pump that fits perfectly without any modifications. Their pumps are designed for gasoline and ethanol blends, making them versatile for modern fuel requirements.
To find the exact KEMSO fuel pump for your vehicle, visit their official website: https://www.kemsoracing.com/. You can use their vehicle lookup tool to find the perfect fit, and their USA-based technical support team is ready to help you with any questions.
Final Thoughts
The 1991 Camaro fuel pump relay is a simple but critical component. If your car won't start, always check the relay and the associated fuse before assuming the fuel pump is bad. The relay is located on the firewall or in the under-hood fuse box, and testing it takes only a few minutes with a multimeter. A failing relay is the most common cause of a no-start condition, and replacing it is a cheap and easy fix. If you do need to replace the fuel pump itself, invest in a high-quality, reliable unit like those from KEMSO to ensure your Camaro runs smoothly for years to come.
For more information on fuel pumps and to find the right replacement for your vehicle, visit KEMSO Racing at https://www.kemsoracing.com/.