A common problem in the summer is difficulty starting when the engine is hot, usually due to flooding. Another seemingly unrelated problem is the annoying "click" when trying to crank the engine. No crank, just "click." These two ailments are, quite often, very related and easily fixed. The installation of the switch and relay to bypass, or engage, the cold start solenoid on the injection pump can cure both problems.
In Fig. 1, the factory wiring is shown. This is how the cars left Arese. In order to alleviate the hot weather flooding, many dealers installed switches usually under the dash or in the steering column nacelle. Fig. 2 shows the simple installation of this switch. Notice that no relay is used. This arrangement won't cure the "click-no crank" problem, however.
The basic problem with either setup, Fig. 1 or Fig. 2, is that the ignition switeh has to energize the starter solenoid and the cold start solenoid. After a few years the contacts in the ignition switch get crusty and the poor ol' ignition switch is lucky to energize one of these solenoids, let alone both. Another problem with the first fix, shown in Fig. 2, is the possibility of meltdown as the half-mile of wire gets hot from cranking the engine and shorts out.
The real fix, with the relay, reduces the amount of current flow through the ignition switch and bypass switch (Fig. 3). Now the ignition Switch starting contact terminal "50," is only required to energize the starter solenoid and the itsy-bitsy coil inside our new relay. The current for energizing the cold start solenoid flows through the relay contacts from the battery cable's connection at the starter. Assuming your ignition switch and starter solenoid are in good condition, this will end the "click-no crank" syndrome.7
The operation of this bypass circuit is quite simple. In fact, most of the time the bypass switch should be left closed, in the "on" position. In this position, the cold start system operates just as it always has. Should the engine flood, or not start promptly when hot, open the bypass switch to cease the cold start solenoid's fuel enriching action. Just don't forget to turn the switch back "on" tomorrow morning!
Parts required:
Note: Use existing black wire from starter to relay blade "85." Just remove from cold start solenoid. Judge mounting location by this wire's length.