Cold Start Injector Connection

[spielzeug]

The Cold Start Injector on my 78 3.0L 911 is not connected. The engine harness has a "pigtail" a few inches right of the throttle linkage that has had the connector removed. I can still start the engine, but I have to really let it turn for a while. My question is, does it matter which wire goes to which terminal of the switch? I am sure I can connect the valve, but I don't want to have it shut instead of open (if that is possible).

Thanks for any help I receive.

[Scott R]

It has a plus and a minus, it's fed from the left side chain box cover, which is fed from the yellow starter wire. Facing the injector the plus is on the left. So you can trace the connection buy checking continuity between the temp sensor on the drivers side chain box cover to the connection in question.

[psalt]

Read the wiring diagram.

The CSV get +12 volts from a yellow wire on the starter only when the key is in the "Start" position. The Thermo Time Switch provides the ground when cold for about 6 seconds, then a heater circuit disconnects the ground to prevent flooding. You will fill the engine with fuel and damage it with incorrect wiring.

[boyt911sc]

Originally Posted by spielzeug

The Cold Start Injector on my 78 3.0L 911 is not connected. The engine harness has a "pigtail" a few inches right of the throttle linkage that has had the connector removed. I can still start the engine, but I have to really let it turn for a while. My question is, does it matter which wire goes to which terminal of the switch? I am sure I can connect the valve, but I don't want to have it shut instead of open (if that is possible).

Thanks for any help I receive.

Spielzeug,

If you still have the original wiring connectors (small & larger) for the thermotime switch, they will only connect one way. The smaller connector (yellow wire) will not connect properly on the big terminal which is intended for the larger connector (red/black). To be safer, let's assume you don't have the original connectors. Inspect the TTS, it has 2 different size terminal connecting points (round disks). The red/black (ground wire) goes to the bigger terminal and the yellow wire goes to the smaller. The power to the CSV comes from the plastic plug connector with guide.

At this time of the year, you'll have cold starting problem because your CSV (cold start valve) is inoperative. Test your CSV to verify it is working while you're there. You can test the CSV with the FP running without starting or running the motor. Keep us posted.

Tony

[spielzeug]

Thanks to all for your help. With the help of my multi-meter, I am sure I can take it from here. Thanks again!

[Alan L]

The CSV is basically a solenoid valve which pulls open against a light spring (which closes it when the solenoid is not energised).
Power either way to the solenoid should energise it - but in other respects, it would be best to get the right connection.
If it is working you should hear/feel a slight click/clunk as it pulls open/shut.
You can dummy test it if you had it out, just by hooking 12 v battery or charger across the two pins briefly.
They often seize up in the bore with rust spots thru lack of use.
Alan