Fuel & Ignition

Air Filter Housing and Air Flow Sensor - Removal and Installation

This procedure is used to remove the air filter housing and air flow sensor on 944s and 944 Turbos. Thanks to Tom Harrison for taking the time to provide fee…

DME Control Unit Chip Installation (Including KLR Chip for Turbos)

Before removing the old chip (Turbocharged cars) make sure you have identified the correct chip for installation. On 1988 model and newer cars this is simpli…

DME Control Unit Removal and Installation

DME Relay Information and Testing

The DME relay which is used on 1985.5 and newer 944s is essentially the same as the fuel pump relay used on early 944s. The fuel pump relay on the early cars…

Fuel Injector and Fuel Rail Removal and Installation

Stuff catch rags underneath the fuel pressure damper and fuel pressure regulator to catch fuel when disconnecting the fuel supply and return lines.

Fuel Injector Information

In this document, I've tried to provide as much information as possible about the Bosch injectors used in 944 and 968 applications. Unfortunately, the inform…

Fuel Pressure - Checking

Refer to FUEL-20(/manual/fuel-ignition/adapter-for-non-metric-thread-fuel-pressure-gauges) for instructions on how to make an adapter for fuel pressure gauge…

Fuel Pressure Regulator - General Information and Replacement

For years, 944 owners and even experienced Porsche mechanics, have on a regular basis replaced perfectly good DMEs, fuel pumps, and various other components …

Fuel Pump Delivery Rate Checking

Be sure to have rags ready to catch excess fuel when disconnecting fuel lines / caps. The fuel in the fuel rail may be under high pressure and may spray if t…

Fuel Pump Information and Replacement

The Bosch fuel pumps used in Porsches are generally extremely reliable and not prone to failure. If you have a fuel pump that needs to be replaced, there is …

Fuel Pump Suction Strainer - Removing, Cleaning, and Replacing

If you have a problem which involves a low fuel system pressure or inadequate fuel pump capacity it may be due to a clogged fuel filter or fuel tank strainer…

Fuel Rail Adapter - Making an Adapter for Non-Metric Thread Fuel Pressure Gauges

If you live in the United States and you want to check the fuel pressure on your 944 you have two choices. The first choice is to buy a fuel pressure gauge w…

Fuel System Leakdown Failure

Fuel System leakdown failures can be caused by a leaking fuel injector(s), a bad fuel pressure regulator (FPR), or a leaking fuel pump check valve. When this…

Idle Control Motor Replacement

If the rubber mounts are broken, the controller and the bracket will come out as one. Remove the bottom section of the broken rubber mounting bolts from the …

Idle Speed Adjustment

Idle speed adjustment is not normally required on 944s. However, the idle speed adjusting screw will sometimes back out causing idle speed to become out of a…

Intake Manifold Removal and Installation

On normally aspirated cars, there are hoses underneath the intake manifold which can not be disconnected from the intake until it is lifted.

Oxygen Sensor General Information, Testing, and Replacement

For 944s which are equipped with oxygen sensors (not all are), the O2 sensor measures the oxygen content in the exhaust and provides an output feedback signa…

Throttle Position Switch - Information, Troubleshooting, Replacement, and Adjustment

A faulty throttle position switch (TPS) can result in a number of poor running problems. Because they can result in such a large number of problems, faulty s…

Distributor Cap and Rotor Replacement

Removing and installing the distributor cap on a 944 can be extremely frustrating. Why? Probably because it seems like such a simple job and often isn't. Onc…

Ignition System Troubleshooting

If you've come to this procedure, you probably suspect that you have a no spark condition. If so, you should have already verified that you actually have a n…

Speed and Reference Sensors - Checking, Replacement, and Adjustment

The 944 Engine Managment system uses two crankshaft sensors. One (Reference Sensor) determines the #1 piston (front of the engine) position relative to Top D…