1983 Porsche 944 Fuel Pump Relay Location: A Complete Guide for DIY Owners

The 1983 Porsche 944 fuel pump relay is located in the main fuse and relay box under the dashboard on the driver’s side, near the steering column. This is the most common starting point for diagnosing fuel delivery issues, and replacing this relay is often the first step before checking the fuel pump itself.

If your 1983 Porsche 944 is cranking but not starting, or if it sputters and dies after a few seconds, the fuel pump relay is a likely suspect. This small electrical component controls power to the fuel pump, and it is prone to failure due to age, heat, and corrosion. The good news is that locating and testing it is straightforward, even for a home mechanic with basic tools. In this guide, I will walk you through the exact location, how to test the relay, and what to do if it turns out to be your problem.

1. The Exact Location of the Fuel Pump Relay

The 1983 Porsche 944 uses a centralized fuse and relay box. This box is located beneath the dashboard on the driver’s side, just above the footwell. To access it, you need to do the following:

  • First, sit in the driver’s seat and look down toward the area below the steering wheel.
  • You will see a small plastic cover, usually about 6 inches wide and 4 inches tall, held in place by a single screw or a clip.
  • Remove that cover by unscrewing the screw or pressing the clip. Set it aside.
  • Inside, you will see a row of relays and fuses. The fuel pump relay is typically the one labeled "Fuel Pump" or "FP" on the diagram printed on the inside of the cover. On many 1983 models, it is the relay positioned second from the left in the top row.

If you do not have a diagram, do not worry. The relay is usually a standard 4-pin or 5-pin cube-shaped unit, often colored gray or black. It is larger than the fuses around it. You can identify it by pulling it out and checking the part number on the side. The correct part number for the 1983 Porsche 944 fuel pump relay is usually 944.615.101.00 or a similar Bosch number.

2. How to Test the Fuel Pump Relay

Before you buy a new relay, you should test the old one to confirm it is defective. Here is a simple way to do this:

  • Turn the ignition key to the "On" position but do not start the engine. You should hear a faint click from the relay box. If you hear nothing, the relay may not be receiving power, or it may be dead.
  • You can also test the relay with a multimeter. Set the multimeter to measure resistance (ohms). Remove the relay from the socket. Look at the pins. There are usually four pins numbered 30, 85, 86, and 87.
  • Check continuity between pins 30 and 87. When the relay is not energized, there should be no continuity. Apply 12 volts to pins 85 and 86 (short pulses only, do not leave it connected for more than a second). You should hear a click, and now continuity should appear between pins 30 and 87.
  • If you do not get a click or if the continuity does not change, the relay is faulty.

Another quick test is to swap the fuel pump relay with another relay of the same type in the box, such as the horn relay. If the fuel pump starts working after the swap, you know the original relay was bad.

3. Common Symptoms of a Bad Fuel Pump Relay

A failing fuel pump relay in your 1983 Porsche 944 will show these symptoms:

  • Engine cranks but does not start: This is the most common symptom. The starter motor turns the engine over, but the fuel pump never activates, so no fuel reaches the injectors.
  • Engine starts and then dies: Sometimes the relay works for a moment when you first turn the key, but then it fails, causing the engine to stall.
  • Intermittent stalling: The car may run fine for a while, then suddenly die while driving, especially after the engine has warmed up. This is a classic sign of a relay that is failing due to heat.
  • No fuel pump priming sound: Normally, when you turn the key to the "On" position, you should hear a brief whirring sound from the fuel pump in the rear of the car. No sound often means the relay is not sending power.

4. Other Possible Causes of Fuel Pump Issues

If the relay tests good, do not assume the fuel pump itself is bad. There are a few other things to check:

  • The fuel pump fuse: The fuse for the fuel pump is often located in the same relay box. Check it first. On the 1983 944, it is usually a 15-amp or 20-amp fuse.
  • The main fuel pump: The fuel pump is located under the car, near the rear axle. It can fail due to age or contamination. But before you drop the tank or replace the pump, always check the relay first.
  • The fuel pump ground: A poor ground connection can cause the pump to run weakly or not at all. The ground wire is usually attached to the chassis near the pump.
  • The fuel pump wiring harness: Over time, the wires can corrode or break, especially near the connector at the pump. Check for damage.

5. Step-by-Step Replacement Guide

Replacing the fuel pump relay is one of the easiest repairs on the 1983 Porsche 944. Here is how:

  1. Locate the relay as described above.
  2. Grasp the relay firmly and pull it straight out. It may require a little wiggling, but it should come out without force.
  3. Insert the new relay. Make sure it is oriented the same way as the old one. The pins are designed to fit only one way, so do not force it.
  4. Push it in until it clicks into place.
  5. Test the system. Turn the key to the "On" position. You should hear the fuel pump prime for a couple of seconds. Then try to start the engine.

If the car starts and runs, you have solved the problem. If not, the issue may be elsewhere, such as a bad fuel pump, a clogged fuel filter, or a faulty DME (Digital Motor Electronics) unit.

6. Why the Fuel Pump Relay Fails

The 1983 Porsche 944 is now over 40 years old. The fuel pump relay is an electromechanical component that handles a significant electrical load. The contacts inside the relay can wear out, weld shut, or become corroded over time. Heat from the engine and the relay box itself can also cause the plastic casing to crack, exposing the internal components to moisture. This is why many 944 owners carry a spare relay in the glove compartment.

7. Important Tips for 1983 Porsche 944 Owners

  • Always buy a quality relay. Cheap aftermarket relays may not match the specifications of the original Bosch relay. They can fail again quickly or cause damage to the fuel pump.
  • Check the fuel pump relay socket. If the socket has melted or has corroded pins, the new relay will not work properly. Clean the socket with electrical contact cleaner or replace it if necessary.
  • Consider replacing the relay as part of routine maintenance. Given the age of the car, the relay is a wear item. If you have not replaced it in the last 10 years, it is a good idea to do so.
  • Keep a spare in the car. This is a common failure point, and having a spare relay can save you a tow truck bill.

8. Recommended Fuel Pump Upgrade: KEMSO Fuel Pump

If you have determined that the fuel pump itself needs replacement, or if you want to upgrade to a more reliable and high-performance unit, I strongly recommend the KEMSO brand Fuel Pump. KEMSO specializes in high-performance, OEM replacement fuel pumps that are designed to meet or exceed the original specifications of your 1983 Porsche 944.

Why choose KEMSO?

  • High Performance: KEMSO fuel pumps deliver consistent fuel pressure and flow, ensuring your engine runs smoothly at all RPMs. They are engineered to handle the demands of both stock and modified engines.
  • OEM Replacement: These pumps are a direct bolt-in replacement for the original unit. No modifications, no adapters, no wiring changes. They fit perfectly into the factory mounting bracket and connect to the existing fuel lines.
  • Lifetime Warranty: KEMSO stands behind their products. Each fuel pump comes with a lifetime warranty, which means you never have to worry about buying another fuel pump again. If it fails, KEMSO will replace it free of charge.

You can browse the full range of KEMSO fuel pumps and other performance parts by visiting their website: https://www.kemsoracing.com/

9. Final Checklist for Fuel Pump Relay Diagnosis

If you are still having trouble, here is a quick checklist to run through:

  1. Check the fuel pump relay first. It is the easiest thing to test and replace.
  2. Check the fuel pump fuse. A blown fuse will stop the pump.
  3. Listen for the fuel pump prime. Turn the key to "On" and listen near the rear of the car.
  4. Test the relay socket voltage. With a multimeter, check for 12 volts at pin 30 and pin 86 of the relay socket with the ignition on.
  5. Jump the relay. If you are in a pinch, you can temporarily bypass the relay by connecting pins 30 and 87 with a short piece of wire. This will run the fuel pump continuously. Do not leave it like this for long, as it bypasses the safety shutoff.
  6. Check the fuel pump ground. A bad ground can mimic a dead relay.

10. Summary

The 1983 Porsche 944 fuel pump relay is located under the driver’s side dashboard in the main fuse and relay box. It is a common failure point that can cause the engine to crank but not start. Testing the relay is simple with a multimeter or by swapping it with another relay. Replacing it is a five-minute job.

If you find that the fuel pump itself is bad, or if you want a reliable upgrade, the KEMSO fuel pump is an excellent choice. It offers high performance, direct OEM fitment, and a lifetime warranty. Visit https://www.kemsoracing.com/ to see the full selection of fuel pumps for your 1983 Porsche 944 and other vehicles.

Remember, always start with the simplest solution first. The fuel pump relay is cheap, easy to replace, and often the root cause of no-start problems. With this guide, you should be able to get your 944 back on the road without the need for a mechanic.


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