Clutch Wire/TMO chip/AT to MT swap

[Salad 419]

I have several simple questions. (I hope). Here's some background info first. I have an '89 Colt that has the 4G63 swap done. The car was originally an Auto Car, so there are no wires hooked up to the clutch switch which I need to tap into to connect to Pin 104 for my stutterbox. At the present, I'd guess that the Neutral Safety Switch wires are just tied together since the car starts anytime. Since I had no wiring harness to tap into, I just ran one side of the switch to ground and one side to Pin 104. This did not work for the stutterbox.

My questions are:

1) Where is the "other"(not the green) wire connect to in the factory harness?

2) What type of "signal" is the ECU getting at Pin 104 on a manual car when the clutch is pressed in?

3) Since it would be the safest thing to do anyway, I'm going to find the Neutral/Park wires and hook them up to the clutch wire. Would tapping these wires once they're attatched to the clutch switch get me the proper signal to Pin 104?

I guess what I'm asking for is a step by step approach to hooking up the Clutch wire and Neutral Safety switch for an AT to manual swap. I searched, but found no good answers.

Thanks in advance,
Salad

 

[steve]

At the present, I'd guess that the Neutral Safety Switch wires are just tied together since the car starts anytime. Since I had no wiring harness to tap into, I just ran one side of the switch to ground and one side to Pin 104. This did not work for the stutterbox.

My questions are:

1) Where is the "other"(not the green) wire connect to in the factory harness?

2) What type of "signal" is the ECU getting at Pin 104 on a manual car when the clutch is pressed in?

3) Since it would be the safest thing to do anyway, I'm going to find the Neutral/Park wires and hook them up to the clutch wire. Would tapping these wires once they're attatched to the clutch switch get me the proper signal to Pin 104?

I guess what I'm asking for is a step by step approach to hooking up the Clutch wire and Neutral Safety switch for an AT to manual swap. I searched, but found no good answers.

Answers based on cars without the optional theft alarm wiring.

1. The other wire runs to a ground. The green wire runs to the starter relay coil and from the other side of the coil to the ignition switch START position.

2. When the clutch is pushed in the switch opens and the signal floats. In the factory wiring the Clutch Safety Switch is normally closed grounding the wire and energising the starter relay coil (also normally closed) to disconnect the +12 from the ignition switch to the starter solenoid.

It's important to know that the ignition switch grounds the START position contact when the switch isn't in the START position. This explains why a diode is required to be installed in the wire to the starter relay when doing the "clutch wire mod" and keeping the CSS function.

The ECU has it's own 12v pullup on pin 104, so with the clutch pedal out it's grounded and with the clutch in (or pin 104 not connected) pin 104 is high. The factory wiring on a MT grounds this pin so without the mod done it looks like the clutch is always out. If you forget to install the diode, when using the normal CSS function and the stutterbox, to block current from the ECU going to the grounded ignition switch it will look to the ECU as if the clutch is always out.

3. I don't understand what your suggesting. I assume you removed the ATX shifter hardware during the swap so the old park/neutral switch is gone.

To restore the factory CSS function you need to find the wire from the starter relay pin 1 and connect that to the clutch switch.

To just use the stutterbox all you need is a wire from ECU pin 104 to the Clutch Switch.

To use both functions, you need a diode installed in the wire to the starter relay bewteen it and the clutch switch and you need the wire from the ECU connected to the clutch switch side of the diode. The banded end (cathode) of the diode goes to the switch and the wire to the ECU. More on blocking diodes

Since yours didn't work when you ran a wire from the switch to the ECU you need to make sure that you used the right switch location (the high one against the firewall), that the switch is normally closed, and that the switch works, grounding the wire with the clutch out and opening with the clutch pushed in.

I hope that covers it.

Steve