Long time viewer, first time poster.

1990 1.6 Turbo Miata MSPNP2

I have read many forums that unfortunately have not helped solve my issue. Launch control will still not activate - please help!

The situation:
- clutch switch was broken, I put a new spring in it and tested resistance, switch is now in working condition

- the jumper to activate the factory upper clutch switch for LC is in place on the board, so to my knowledge, none of the next steps should even be necessary

- spliced into the brown/white wire and pinned it into the launch pin on the options port, still no LC

- pinned it into the clutch switch pin on options port, still no LC

- pinned it into the tableswitch pin on options port, switched the input pin in TunerStudio, still no LC

- put jumpers on the lower clutch switch and neutral safety switch for trans, still no LC

I’m pretty much at a loss here and not sure what else to try. Regardless of what hard limit or tps above value I enter, LC still won’t activate.

Thanks in advance!!

Regards,
Your local YouTube mechanic

 

Have you unplugged the Cruse Control neutral safety switch on the transmission? IIRC this is wired in a way that if you are using the cruse control top switch for LC activation, it will prevent it from activating it.

There are two things that plug in down there, this and the reverse lights, make sure you do not undo the wrong one.

 

I have tried it with the nuetral safety switch plugged in, unplugged, and jumped. All give the same result. I have tried so many different things at this point and am left to assume it’s the TPS. I ordered a VTPS to convert the stock one and I’ll see if that fixes it.

 

What I mean then is it has to stay unplugged, if it is plugged in now, then no matter what you do, it will not work as it will constantly be grounded and deactivating LC.

What does your LC page look like?

 

I’m at work currently, I can post a picture later but I believe it’s at 2k hard limit (for testing purposes), 100 soft limit, 5 degrees advanced, tps above 10. Not sure how it even figures that given that it’s not a vtps.

 

That is going to be an issue, you need to disable that TPS, set it to 0 or -10 if it allows, if you dont have a variable TPS, so you never hit it, and it can never activate, it is keeping everything from doing anything. Set it so it cant go into LC or into flatshift at 1500, so it does not activate LC during normal driving, and then looks for the clutch input, and then revlimits to 2000

What does TunerStudio say the TPS value is at during normal driving now? IIRC the 89-93 Miatas TPS only was a full throttle detector and that was it.

 

Yeah, I was reading the sticker on the TPS and it said something like >15% and <75% so those are the only 2 inputs. My TPS value does not change in tunerstudio when applying throttle.

I have tried 0 for the TPS value but I haven’t thought about entering a negative value because I didn’t think it would accept that. I can give that a shot and see if it works.