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Old 08-14-2013, 06:15 PM   #1
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Default Help with launch control

I have a DIYPNP, everything is set up to use launch control, but here is the kicker. The launch control works when the clutch is depressed and when it isn't depressed, but it will not work with the clutch depressed and it is in gear. I tried unhooking the neutral safety switch, when I do that it doesn't work at all.

Any suggestions?
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Old 08-14-2013, 06:27 PM   #2
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there is nothing that tells the ms that its in 1st gear. im guessing your clutch switch is janky. its not supposed to work both depressed and not depressed

thats what the switch is for. otherwise you'll just have really low rev limit

also I think your tps might have something to do with this
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Old 08-14-2013, 06:36 PM   #3
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Well what is weird is if the car is in gear it will rev to the normal 7200 rev limiter.

I have the tps unhooked, I will try and climb up under the dash and change the clutch switch.
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Old 08-14-2013, 06:39 PM   #4
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so how is it disengaging launch control then?

your speed is mechanical through a cable right? so the ms doesn't know how fast the car is moving. so how could it engage lc with both depressed and not depressed pedal and still have the rev limit at 7200? doesn't add up.
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Old 08-14-2013, 06:48 PM   #5
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When it goes into gear it disengages it, it has the neutral safety switch.

Yeah, it's mechanical speedometer.

I can log it for you if you'd like.
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Old 08-14-2013, 07:11 PM   #6
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So unplug safety switch.
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Old 08-14-2013, 07:52 PM   #7
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What safety switch?
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Old 08-14-2013, 09:32 PM   #8
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You have to disconnect the safety switch that goes to the transmission

It is for the cruse control, if it pops out of gear it disables it.. with the MSPNP way of wiring the sensors for the traction control, it will not enable it until you unplug those wires


from the manual for the PNP:

Quote:
The launch control is based on a rev limiter. This is configured from the Extended → Launch Control dialog. Often the best way to control this is with the stock clutch switch which opens/closes a circuit based on the clutch pedal position. Note that often this circuit also runs through the neutral safety switch on manual transmission vehicles. This means that if you turn launch control on using the stock clutch switch, it will activate when the transmission is in neutral or when you push down the clutch. So when the trans is in neutral, you'll have a launch control rev limiter. When you push in the clutch and put the trans into first gear, you'll also have a launch control rev limiter (which is when you want it) every time after you first put the car in gear and take your foot off the clutch. When you have the launch control active, the rev limits drop to the limits specified on the launch control screen, letting you rev the engine up to a fixed RPM that you can adjust. When you release the switch, the rev limit is removed and you take off… nice and controlled.
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Old 08-14-2013, 10:47 PM   #9
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Vladi Vlad nailed that **** on the head... pics to follow... the spring for the clutch switch to the ECU was broke in 4 positions and was stuck. So I took the switch apart, went to the hardware store got a new spring, put some dielectric grease in it and put it back together. It works now, and yes, the neutral switch on the transmission is disconnected.

Video of launch control will be posted soon

Thanks guys.
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Help with launch control-null_zps38030b17.jpg  
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Old 08-14-2013, 11:53 PM   #10
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oh boy this thing is going to launch so hard lol
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Old 08-15-2013, 12:36 AM   #11
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In for vids of broken axles from launch control glory
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Old 08-15-2013, 11:37 AM   #12
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FYI you can get the speed signal from the NA speedo, it does exist, 4 ground pulses per rotation of the speedo cable, so you just need a pullup. On my car its a complete noisy mess though. At some point I'll add a filter to it.
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Old 08-15-2013, 11:44 AM   #13
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This car hooks up ridiculously good off the line even without LC. I was surprised. I just hope LC actually helps because I can't imagine the car taking off much harder than it does. Unless that was just a lucky exception when you did it with me in it
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Old 08-15-2013, 11:52 AM   #14
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Quote:
Originally Posted by Leafy View Post
FYI you can get the speed signal from the NA speedo, it does exist, 4 ground pulses per rotation of the speedo cable, so you just need a pullup. On my car its a complete noisy mess though. At some point I'll add a filter to it.
the signal goes into your ECU harness, bro. but why would he need it?
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