Only .3v from the black/red ignition wire?
 

We are hooking up the clutch switch to 1Q on the ECU.

We converted from AT->MT and everything works fine. We tapped into the fat black with red stripe ignition wire and it goes to the clutch switch. From the clutch switch we have a wire that goes out to the starter. That all works fine and the starter won't work if the clutch isnt depressed.

So my plan was to tap into the wire that goes from the clutch switch to the starter and feed a relay. That way when the clutch was depressed the relay would trip and 1Q would be ground.

The problem I'm having is that the fat black with red stripe wire is only moving 0.3 volts. And while that seems like enough to let the starter fire it isnt enough to switch on my relay.

0.3 volts seems like a bizarre voltage and I took the DMM to the battery and it read 11+ volts.

Any ideas?

TIA

Here's my theory. The fat black with red stripe wire only gets 12v when the key is in the start position. It is what triggers the starter to fire off.

If that's the case, then I either need to fab up a bracket and another switch for the 1Q line, or remove the clutch interlock function and use the existing switch for the 1Q clutch sensor.

Sound right?

the black/red wire only gets power when turned to crank like you said, it comes from the black/blue wire off the ignition switch, goes to the engine bay through the starter cut relay(controlled by the factory alarm) next to the main relay, back into the cabin, through the clutch switch, back out the firewall to the starter spade connector.

it's a redundant, stupid and easily bypassed system that fails too often.

https://imageshack.us/a/img29/9452/14392735.png

sorry for the slightly too small picture.

Ha! Thx. I had that same page up in the wiring diagram PDF!

Just use both the Interlock and Clutch Switches and leave it at that.

i believe he needs the switch for the ECU, since the auto didn't have it. in that event you can run a wire from the black/blue from the ignition all the way to the starter and use the switch however it suits your needs.

or find a donor car with both switches and pull the one you need. it's been a while but i believe the one at the firewall is for the starter, the one at the top of the pedal travel is for the ECU.

Yes, we dont have an interlock (dont start if clutch isnt pushed) switch - the one closest to the firewall. I'm guessing the pedal set we bought was an 86 because as I understand it they didnt have the interlock switch. For the last several years we've been using the clutch switch as the interlock.

We just took the clutch switch out of the line from the fat black with red stripe wire to the starter and so now the car starts even if the clutch isnt depressed. Then we ran a line from 1Q to the clutch switch and from there to ground. Now the car doesnt die at stop lights.

I suspect if you didnt touch the clutch and smacked the shifter into neutral that it may die. If we get motivated we'll see if the tranny's neutral switch works and if it does we'll hook it into 1Q. That way if either the clutch pedal is pressed or the tranny is in neutral the ECU will compensate on decel and not let it die.

Thanks, guys.