I'm trying to find the PCM wire to splice into (clutch start switch) to activate the launch RPM limiter on my MSD Digital 6 Plus ignition box. I've searched here, LS1Tech, Google, shoebox's site and have found nothing. Car in signature. Any help would be appreciated.

 

It doesn't involve a wire to the PCM. Shoebox has the 95 ignition switch wiring diagram, which shows the clutch swtich, and how it interlocks with the starter via the ignition switch. Look at the lower right corner, which shows both the manual trans clutch switch and the auto trans shifter range switch. Appears to be a yellow wire:

http://shbox.com/1/ignswschematic.jpg

 

Fred
It's funny, I figured you'd probably be the first person to respond.

The thick yellow wire coming off the clutch switch is what I have the launch RPM activation wire hooked to now, but it doesn't seem to be working right. When I took the car out to test it, it seemed to limit at around 4500 RPM all the time (launch and maximum RPM). The next time I get down to drive the car, I'll give the dials on the box another look-see and make sure they're set right.

 

Update:
There are two thick wires (about 14 gauge), yellow and brown, going into the switch that is depressed when the clutch is disengaged. I have the blue 2 step activation wire tapped into the yellow wire, and checked all the dials, and it did the same thing (limiter kicked in at about 4500rpm regardless of clutch position). I also tried tapping into the brown wire, and the same thing happened.
To test the box, I wired the 2 step activation wire directly to the battery, and it works right. Then I disconnected that wire and set the max limit to 5000rpm, and that circuit also works correctly, so the box is fine.
Apparently, there isn't 12V going to/from the clutch switch after the car is started, so it looks like I'm going to have to find another way to activate the 2 step function (switch/relay).

 

I cut the yellow and brown wires going to the clutch start switch plug, and spliced them together. Then, I wired a switched 12v source (the same source I tapped into for my shift light/tachometer and it works fine) into one side (yellow wire) of the plug, then connected the blue activation wire to the other side (brown wire) of the plug. Now my car starts without depressing the clutch pedal, which I could live with if the d@mn rev limiter worked right.
WTF over?

 

I have mine wired through a switch activated by the shifter in first gear then though a DPST switch and the clutch switch. When the DPST switch is one way the clutch switch activates the 2-step and the other way the starter works.

I'm not far from you and would be glad to help you figure yours out sometime.

 

Thanks for your response. What you have setup makes good sense, and keeping the clutch start switch functioning correctly, unlike mine now.
What kind of switch specifically did you use in the shifter (momentary on/off normally open microswitch)? I would like to use exactly what you have for the shifter so I know the setup will work; also I'm assuming any old DPST switch wired in series between the shifter switch and clutch switch will do.
I guess it's just me, but I wish I could get it so it doesn't take 3 switches to activate one function.
If you run at Bremerton at all, maybe I'll see you around there sometime next season. I haven't made it there this year, as I've been mainly running the 1/8th mile down at Riverdale Raceway (Toutle, WA).