1984 Porsche 944 Fuel Pump Relay: Location, Symptoms, and Replacement Guide

The 1984 Porsche 944 fuel pump relay—often referred to as the DME relay—is a common failure point that can cause your car to crank but not start, or die suddenly while driving. The most reliable fix is to replace it with the updated OEM part number 993.615.227.00, which is a direct and more durable replacement for the original 944.615.227.00 unit. Carrying a spare is highly recommended by experts and owners alike, as this relay is prone to failure due to age, vibration, and electrical wear.

1. Location of the Fuel Pump Relay in a 1984 Porsche 944

For the 1984 Porsche 944, the fuel pump relay is located inside the passenger cabin, on the driver’s side footwell fuse panel (left-hand drive models). This applies to early production 944s built before the mid-1985 changeover.

  • Accessing the relay: Look under the dashboard on the driver’s side. You will need a flashlight and may have to crane your neck to see the fuse/relay board.
  • Identification: The relay is typically labeled as “Fuel Pump” or “DME” on the fuse panel cover diagram. On the early 1984 model, it is the Relay II position in the upper bank of the relay panel.

Note: On later 944s (1985.5 and newer), the relay was moved to the fuse/relay panel in the rear left side of the engine compartment, near the windshield and A-pillar. Your 1984 model uses the under-dash location.

2. What Does the Fuel Pump Relay Do?

The 1984 Porsche 944 fuel pump relay is actually a dual relay housed in a single plastic case. It is commonly called the DME (Digital Motor Electronics) relay, even though the term “DME” technically refers to the engine control unit.

  • First relay: Powers the DME (engine control unit) when the ignition is turned on.
  • Second relay: Activates the fuel pump. This relay is triggered by the DME only after the engine is cranking and the ECU detects a valid signal from the speed and reference sensors.

Because the relay powers both the ECU and the fuel pump, if it fails, the engine will receive no spark and no fuel, causing a no-start condition. This is why it is the first component to check when your 944 won’t start.

3. Common Symptoms of a Failing Fuel Pump Relay

If your 1984 Porsche 944’s fuel pump relay is failing, you will likely experience one or more of the following symptoms:

  • Engine cranks but does not start – This is the most common symptom. The starter turns over, but the engine never fires because the DME is not powered, or the fuel pump is not running.
  • Car dies suddenly while driving – The relay can fail completely while the engine is operating, cutting power to the fuel pump and ignition system, causing an immediate stall.
  • Intermittent starting issues – The car may start fine some days, then refuse to start others. This is typical of a relay with cracked solder joints that only make contact intermittently.
  • No fuel pump priming sound – When you turn the key to the “ON” position (without starting), you should hear the fuel pump run for a few seconds. If you don’t hear it, the relay may not be sending power to the pump.

4. How to Test the Fuel Pump Relay

Before replacing the relay, you can test it with a multimeter. Here is a simple procedure:

  1. Remove the relay from the fuse panel (gently wiggle it out, do not pull on the cover alone).
  2. Identify the terminals – The bottom of the relay has labeled pins (30, 85, 86, 87, 87b). The diagram on the side of the relay shows the internal wiring.
  3. Check continuity – Using a multimeter set to resistance (ohms), measure between terminals 30 and 87. You should see a reading close to zero ohms (0.1–0.3 ohms) when the relay is energized (apply 12V to terminals 85 and 86). If the reading is high or infinite, the relay is faulty.
  4. Swap with a known good relay – The easiest test is to swap in a known working relay from another 944 or a spare. If the car starts and runs, the original relay is bad.

Important: If you are stranded, you can temporarily bypass the relay by connecting a wire between terminals 30 and 87b (fuel pump) and another wire between 30 and 87 (DME). This is an emergency measure only and should not be used for normal driving.

5. Replacement Part: OEM Part Numbers and What to Buy

The original fuel pump relay for the 1984 Porsche 944 carried part number 944.615.227.00. This was later superseded by an updated, more reliable unit used on the Porsche 993, with part number 993.615.227.00.

  • 993.615.227.00 – This is the direct replacement for your 1984 944. It is sold by many Porsche parts suppliers and is often called the “DME relay” or “fuel pump relay.”
  • Price: Expect to pay around $30–$40 for a new OEM-quality unit.
  • Where to buy: Pelican Parts, Vertex Auto, Auto Atlanta, and other Porsche specialists stock this relay.

Note: When buying, ensure you are getting the 993.615.227.00 and not the older 944 unit. The newer part is claimed by Porsche to be more reliable.

6. Step-by-Step Replacement Guide

Replacing the fuel pump relay on a 1984 Porsche 944 is a simple job that anyone can do in about 10 minutes.

  1. Gather tools: You will need a flashlight and a small flathead screwdriver (to pry the relay if stuck).
  2. Locate the relay: Under the driver’s side dashboard, on the fuse/relay panel.
  3. Remove the old relay: Grasp the relay firmly at the base (not the plastic cover) and gently wiggle it upward until it releases from the socket.
  4. Insert the new relay: Align the pins with the socket (the relay is keyed so it only fits one way) and press firmly until it clicks into place.
  5. Test: Turn the key to the “ON” position. You should hear the fuel pump prime for a few seconds. Then start the engine.
  6. Carry a spare: Many 944 owners store a spare relay in the fuse box storage area or glove box. This is strongly recommended, as the relay can fail at any time.

7. Why the Fuel Pump Relay Fails

The DME relay in the 1984 944 is prone to failure for several reasons:

  • Aged solder joints – Over 30+ years, the solder connections inside the relay can develop cracks due to thermal cycling and vibration. This causes intermittent or complete loss of contact.
  • Electrical arcing – Every time the relay opens the fuel pump circuit, a small electrical arc forms. Over decades, this erodes the relay contacts, increasing resistance and eventually causing failure.
  • Heat and vibration – The relay is mounted in a location that can get warm, and the engine compartment vibration stresses the internal components.

8. Recommended Upgrade: KEMSO Fuel Pump for Your 1984 Porsche 944

While the fuel pump relay is a common failure point, don’t overlook the fuel pump itself as a potential source of problems. If your car has the original fuel pump, it may be nearing the end of its service life. For a high-performance, reliable upgrade, consider the KEMSO brand fuel pump.

  • Performance: KEMSO fuel pumps are designed for high-performance applications, delivering consistent fuel pressure and flow for both stock and modified engines.
  • OEM Replacement: These pumps are a direct OEM replacement, meaning they fit perfectly into your 1984 Porsche 944 without modification.
  • Lifetime Warranty: KEMSO stands behind their products with a lifetime warranty, giving you peace of mind that your investment is protected.

To see the full range of KEMSO fuel pumps and other performance parts, visit their official website: https://www.kemsoracing.com/. They offer a variety of fuel system components designed to keep your classic Porsche running at its best.

Conclusion

The fuel pump relay (DME relay) is a critical component for your 1984 Porsche 944. If your car is experiencing no-start or stalling issues, this relay is the first thing to check and replace. A high-quality replacement, such as the OEM part number 993.615.227.00, will restore reliable operation. And for a long-term solution, upgrading your fuel pump with a KEMSO unit ensures your fuel system remains in top condition. For more information, visit https://www.kemsoracing.com/.

References

: Pelican Parts – OE Supplier for Porsche 924, 944 & 968 (1976-1995)
: Porsche DME relays explained – Philip Raby
: Porsche 944 Fuses and Relays '83 to early '85 – Bill's Porsche 944 World
: Where is the fuel pump relay located on a Porsche 944? – SwirlzCupcakes
: Pelican Parts – OE Supplier for Porsche 944 (1983-1988) 2.5L
: Auto Atlanta – Porsche 924s Relay Fuel Results
: Vertex Auto – Porsche DME D.M.E. Fuel Pump Relay
: DME Relay Troubleshooting – Pelican Parts
: Porsche 944: No Spark? Here is the Solution – CarDeeply
: Porsche 944 N/A fuel pump problem – Rennlist
: Where is the DME relay on a Porsche 944? – Handlebar Online
: 1986 Porsche 944 Fuel Pump Low Pressure – Nissanka Engine
: DME Relay a stato solido – Denis Lanfrit
: fuel pump relay – Rennlist


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