Answer
Jun 18, 2025 - 02:27 AM
A crank-no-start condition doesn’t always mean the fuel pump is bad — it’s important to confirm first. Check the fuel pump fuse and relay. Then, using a multimeter or test light, verify whether there’s voltage at the fuel pump connector while cranking. If power is present and there's still no fuel pressure, then yes — the pump is likely the culprit.
If you’ve ruled out all other causes and confirmed it’s the pump, here’s how to replace it on the 1989 Riviera:
1. Accessing the Fuel Pump
The fuel pump is located inside the fuel tank, and unfortunately, there’s no access panel — you’ll need to lower the tank. Raise the rear of the vehicle and support it securely with jack stands placed under the frame rails. Avoid placing stands under the suspension components.
2. Depressurizing the System
Disconnect the negative battery cable. Then remove the fuel cap to release residual vapor pressure. If you have a fuel pressure gauge, you can depressurize the system via the Schrader valve on the fuel rail — wrap it in a towel to catch spray. If not, cranking the engine with the fuel pump relay pulled may help drain residual pressure.
3. Disconnecting the Fuel Tank
Locate the fuel tank just ahead of the rear bumper. Disconnect the fuel filler neck hose and vent line from the tank — expect these to be stiff and possibly brittle. Then, using a fuel line disconnect tool, detach the quick-connect fuel lines leading to the pump/sender unit. Finally, unplug the fuel pump electrical connector near the top of the tank or along the frame rail harness.
4. Removing the Tank and Pump
Support the fuel tank with a floor jack and remove the two tank retaining straps (one on each side). Carefully lower the tank enough to access the top. You’ll see the fuel pump assembly secured by a metal locking ring — tap it counterclockwise with a brass drift and hammer to loosen. Once free, carefully lift the sender/pump unit out of the tank, taking care not to damage the fuel level float arm or the sock filter.
5. Reinstalling the New Pump
Inspect the old pump’s orientation before removal so you can match it during reinstallation. Replace the O-ring seal — don’t reuse the old one if it’s cracked or swollen. Lower the new pump assembly into the tank carefully, ensuring a proper seal. Reinstall the locking ring and verify it’s fully seated. Then raise the tank and reconnect all fuel lines, vent hoses, and the electrical harness. Bolt the straps back in place and lower the car.
6. Final Steps
Turn the ignition key to the ON position (without starting the engine) and leave it for 3–5 seconds. Do this two or three times to allow the fuel pump to prime the system. Then start the engine. If all was done correctly, it should fire up.
Hope that helps!
