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Gear slip in brake launch, loss of power

Started by Carstar33, May 31, 2015, 01:11:20 AM

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Carstar33

May 31, 2015, 01:11:20 AM Last Edit: May 31, 2015, 01:13:10 AM by 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

#1
May 31, 2015, 06:05:38 AM
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.
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

SHOnUup

#2
May 31, 2015, 07:32:48 AM
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

2011 Sterling Gray Metallic SHO non PP,
12.4211 @ 110.28 Livernois 3bar tune & CAI,
Added since...PPE catless Dpipes, Megan coilovers, Powergrid adjustable end links, and EBC slotted rotors and red stuff pads.
Tommy Designs grille with carbon fiber hydrographics, fender badges and fog bezels hydrodipped also, tinted windows, head & taillights, debadged trunk with all chrome plasti-dipped, black calipers, obdlink mx scantool running torque pro on 7" tablet.

ShoBoat

#3
May 31, 2015, 11:35:12 AM
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.


Sent from my iPhone using Tapatalk
2012 Pearl White CTS-V Stock
2016 Fusion Titanium 2.0 EB Stock
2013 SHO Black on Black (Gone) PP, Unleashed Custom Tune, 170 TStat, SP534 Plugs, 3 Bar, Airaid Intake, PPE catted downpipes, Corsa Cat-back, H&R Springs. Focal 165KR Front Stage,2 JL W6 10 with Focal 800.1. 12.62 @ 110 mph.

Carstar33

#4
May 31, 2015, 01:35:23 PM
Quote from: SHOdded on May 31, 2015, 06:05:38 AM
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

#5
May 31, 2015, 03:20:13 PM Last Edit: May 31, 2015, 10:32:09 PM by 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!
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

ZSHO

#6
May 31, 2015, 03:48:25 PM Last Edit: May 31, 2015, 03:57:04 PM by 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.


2013 Performance Package SHO| Livernois Custom Methanol Tune|3-Bar Map|Reische-170-Stat|Full Race Tial-10psi BOV in Black|PPE-Gloss Black Hot Pipes|EPP Dual Intake in Gloss Black|PPE Catted DP|Corsa Sport Cat Back Exhaust|H&R Sport-Springs|CFM Performance Billet Valve Cover Breather In Gloss Black|Llumar 20%Ceramic window Tint|MSD Ignition Coils in Black|Extreme Roof Spoiler|Redline Fluids all around|Gearhead Intercooler|First-SHO With Direct Port Alky-VP-M1-100%-Methanol Injection|LMS-Custom-Dyno-Tuned @ 415whp-465wtq| Best Trap Speed of 115.54 mph|

Carstar33

#7
May 31, 2015, 08:00:14 PM
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

#8
May 31, 2015, 10:32:31 PM
Great to hear :thumb:
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!
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