Replacing The Fuel Pump In Your 1985 Pontiac Fiero: Step-By-Step Guide

Replacing the fuel pump on a 1985 Pontiac Fiero is a complex process that requires careful attention to safety. The fuel pump is located inside the fuel tank, which must be removed from the car. This task is made more challenging by the shape of the tank and the presence of rusted bolts and clamps. Before beginning, it is important to perform tests to confirm that the fuel pump requires replacement. These tests involve observing whether the pump primes the fuel system when the key is turned on and checking if the pump runs while cranking the engine until the oil pressure warning light goes out. If the pump is confirmed to be faulty, the next step is to locate and disconnect the fuel pump harness, which is found along the firewall. The fuel tank can then be removed by first jacking up the car and placing it on jack stands, then using a floor jack to support the weight of the tank while removing the bolts and clamps holding it in place. It is recommended to disconnect the hoses after the tank is lowered away from the car, providing more room to work. Additionally, the heat shield on the firewall should be removed, and the radiator tubes may need to be pulled out of the way. Throughout the process, it is crucial to use proper safety equipment, such as safety glasses or a full-face shield, and to have fire extinguishers nearby when working with gasoline.

The fuel pump is located in the tank, which must be removed

To replace the fuel pump on a 1985 Pontiac Fiero, you will need to remove the fuel tank, as the pump is located inside it. Here is a step-by-step guide to help you through the process:

First, ensure you have the necessary tools and a replacement fuel pump. In addition to standard tools, you will need a 10mm and a 7mm socket, pliers or Channellocks, and possibly a jack to support the weight of the fuel tank. It is also recommended to have an ABC fire extinguisher nearby as you will be working with gasoline.

Next, locate the wiring harness that runs from the top of the fuel tank, through the firewall, and up the back of the passenger compartment. This will need to be disconnected and removed along with the fuel tank.

Now, disconnect the negative power cable from the battery. You will be working with gasoline, so this is an important safety precaution.

Then, mark the fuel hoses with a series of dots or use a paint pen to indicate where they came from and where they will need to go back. This will ensure that you can correctly reconnect them later.

Before removing the fuel tank, you will need to remove the crossmember, which is held in place by four 13mm bolts. Loosen these bolts, but do not remove them completely yet.

Now, it's time to remove the fuel tank. Place a drip pan or a gas-soaked rag underneath to catch any fuel drips. Remove the two nuts securing the tank straps, and bend them out of the way. Be careful not to bend them too much, as they may be rusty and weaken easily.

With the straps removed, carefully lower the fuel tank. It may catch on various components, so be patient and work it out slowly. Once the tank is free, slide it towards the back of the car a little to make things easier.

Now that you have access to the fuel pump, it's time to remove the old one and install the new one. The fuel pump is held in place by a lock ring, which needs to be removed carefully. Do not force anything, as you may damage the assembly. Twist, turn, and gently manipulate the lock ring until it comes off.

With the lock ring removed, carefully remove the old fuel pump. Take note of the position of the filter strainer on the bottom of the assembly, as you will need to install the new fuel pump in the same orientation.

Install the new fuel pump by sliding it into the carriage and connecting the rubber hose connector to the fuel pump nipple. Secure it with the provided clamps. Attach the filter screen in the same way as the old one.

Before reinstalling the lock ring, wipe down the sealing surface to remove any dust or dirt. Then, reinstall the lock ring and turn it until the tabs are fully seated against the tank-mounted portion of the lock ring.

Now, it's time to reinstall the fuel tank. Carefully slide the tank back into place, being careful not to slosh the fuel. Reattach the crossmember and tighten the bolts.

Reconnect the fuel hoses, ensuring they are correctly aligned with the marks you made earlier. Use a light coat of oil on the nipples sticking out of the tank to make this process easier and to prevent damage to the hoses. Tighten the hose clamps once they are in place.

Finally, reconnect the wiring harness and the negative battery cable. Verify that there are no fuel leaks before starting the car. Turn the ignition to the "on" position and check the fuel pressure. If there is no pressure, turn the key off and then back on. Check for leaks again. If there are no leaks, start the car and enjoy your newly replaced fuel pump!

Disconnect the hoses after the tank is away from the car

To disconnect the hoses, use a combination of spring-loaded clamps, screw clamps with 8mm heads, and 1/4” heads. You will need a 7mm socket to remove the four screws on the heat shield on the firewall.

It is recommended to disconnect the hoses after the tank is away from the car, as this gives more room to work and allows the tank to move around if needed.

The tank has to be manoeuvred out carefully due to its shape

The clamps on the hoses are hard to get to and don't want to come off. They have to be dealt with after the tank comes down a little way. Don't forget to disconnect the wiring beforehand!

The fuel pump harness is located along the firewall

To remove the fuel tank, you'll first need to disconnect the negative power cable from the battery. Then, locate the four 13mm bolts holding the crossmember in place and remove them. The fuel tank is held in place by straps that are secured with one 13mm nut each. Remove the nuts, and the straps will swing down, allowing you to access the fuel tank. Be careful not to bend the straps too much, as they may be rusty and weak.

Once the straps are out of the way, you can start to lower the fuel tank. This can be tricky, as you'll need to support the weight of the tank while lowering it. It's important to be patient and work the tank out slowly, as the edges can catch on things. Once the tank is free, roll out from underneath it and set it on the ground.

With the fuel tank removed, you can access the fuel pump and begin the replacement process. Remember to work carefully and take your time to avoid any damage or injuries.

The fuel pump relay is located in the designated plug

To replace the fuel pump on a 1985 Pontiac Fiero, you'll need to locate the fuel pump relay. This can be found on the front firewall of the engine compartment, to the left of the driver's side deck lid hinge mount. If your 1985 Pontiac Fiero has air conditioning, the relay will be right next to it.

Now, the fuel pump relay has two parts. If you're jumping the contacts, you need to also consider the coil that actuates those contacts. Look at the two coil terminals in the socket. Typically, one will have 12 volts, and the other will be grounded by the Engine Computer or oil pressure switch to turn the relay on.

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