Gear slip in brake launch, loss of power

[Carstar33]

I recently got the LMS stage 4+ and it has been great. I tried a launch (about 2500rpm) today and it chirped, shuttered and felt like something slipped internally. It then cut power and wouldnt accelerate. I pulled over, shut it off and then started it and it went just like nothing had happened. No codes or anything.

I have had quite a few successful and very smooth launches, bit of wheel chirp and away it goes. I know there are quite a few threads on here about slipping in higher gears, but none off the line including brake launching/boosting.

Any help would be appreciated. PTU, RDU, Trans all serviced less than 500kms ago. 85000 km on it now.

 

[SHOdded]

Welcome, Carstar, glad to see you here!  Do you have a SHO or MKS?  What year, if a SHO does it have the PP package?  What tires and how much mileage on them?  Road surface temperatures?  Vehicle warmed up before the brake launch?

Normally, after a tune, brake launches over 2000 rpm (especially at standard tire pressures) are too much power for the drivetrain to handle and the PCM will cut power to save it.  Untuned, 2500 would have been OK.

 

[SHOnUup]

What he said ^^^

TCS on will cause this too. I've had car fall on its face during the brake boost at 2500 rpm's. Still haven't gotten limp mode after take off though, that's with some violent wheel spin too(knocking on wood).

Rich

 

[ShoBoat]

Same here, I've had it cut power after a hard launch where there was a lot of wheel spin. But it recovered right after I let off. But this has not happened since I changed my tires to the Pilot SS.


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[Carstar33]

Welcome, Carstar, glad to see you here!  Do you have a SHO or MKS?  What year, if a SHO does it have the PP package?  What tires and how much mileage on them?  Road surface temperatures?  Vehicle warmed up before the brake launch?

Normally, after a tune, brake launches over 2000 rpm (especially at standard tire pressures) are too much power for the drivetrain to handle and the PCM will cut power to save it.  Untuned, 2500 would have been OK.

2010 SHO, non PP, 85 000km, orignal tires maybe with 35 000km on them (canadian winters, snow tires for 6 months of the year). Temperatures was about 20 degrees C outside, not sure about the surface temps. And yes it was plenty warmed up, I dont play until it is.

TCS was on, I guess i just was used to launching high from stock.

 

[SHOdded]

Ok, so:  1) Try launching between 1900-2000 rpm, 2) verify the knock sensor wiring is not chafing, 3) don't worry about TCS because you can't do anything about it!

 

[ZSHO]

It could be something hopefully simple like a faulty abs/speed sensor,after a while they get dirty and the contacts get corroded by the wheel well causing the car to go into limp mode.

 

[Carstar33]

Yeah I just was launching it too high (2500-2800). I went for a ride today and did it between 1900-2200 and it was just fine.

 

[SHOdded]

Great to hear :thumb: