Volkswagen Air-Cooled 1970-1981 Repair Guide

Fuel Injectors


There are two types of injectors. One type is secured in place by a ring that holds a single injector. The second type of injector is secured to the intake manifold in pairs by a common bracket.


When the engine fails to run or runs erratically, always check the ignition system before assuming that the problem lies under that inscrutable tangle known as the fuel injection system. If the ignition system is functioning correctly, remove the injectors from the engine, leaving the fuel lines and wiring connected to them. Disconnect the high tension cable from the ignition coil to prevent the engine from starting and have an assistant engage the starter briefly.

See precautions in Tune-up for electronic ignition.

Raw fuel will be sprayed from the injectors if they are working, so have a container ready and do not smoke.

If a cone-shaped mist of fuel sprays in pulses from all of the injectors, they are working properly. If one or more injectors fail to spray, check the fuel injection signal.

To check for injector leakage, wipe the tips of the injectors dry with a clean, lint-free rag, then turn the ignition to ON (not START ). If the injector tips become wet with fuel but do not drip more than one or two drops per minute, it is a good possibility that the pressure regulator is set too high; if the injector loses more than one or two drops per minute, the injector is faulty and should be replaced.


You will need a mechanic's stethoscope to perform the second part of this test.

Unplug the electrical connector on the fuel injector and connect the leads of a test light to the two terminals of the connector. Disconnect the ignition coil high tension cable to prevent the engine from starting and have an assistant engage the starter.

See Precautions in Tune-up for electronic ignition.

The test light should blink, indicating the pulses of the injector.

Reconnect all fuel injector connections and run the engine. Place the end of the stethoscope on the fuel injector body. You should hear a clicking sound indicating that the injector is working properly. Failure to hear a clicking sound or hearing a sound different from the rest of the injectors probably indicates a faulty injector.


See Figures 1 and 2

Click image to see an enlarged view

Fig. Fig. 1: Carburetor Specifications

Click image to see an enlarged view