Failsafe back!!! 2008 gt500

Joewee500

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I've also read that the U0300 code could mean that the strategy is wrong with my tune. Don't know why that would come up after 2 years though. I'm grasping at everything I guess


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69b302

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A Failsafe occur when the engine performs much different than the TB and MAF data(other stuff too) indicate it should. Either over producing or under producing the expected torque, given a certain and load and airflow. I would check for vacuum leaks, as you seem to indicate the Failsafe occurs mostly on WOT and not around town. I agree with trying a different TB(even stock) to eliminate any chance of a TB issue. What are your fuel trims?
 

Joewee500

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Every vacuum line has been replaced and I couldn't locate a vacuum leak. I was wondering if the cold weather created a situation that threw the tune outside a torque limit.


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69b302

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It is possible that the colder air air is causing a table to be maxed out, and causing the failsafe(since the car is making more power with the denser air). I live in upstate NY, and a tune can be weather/temp sensitive(if it's off). Has your tuner had any feedback on the issue?
 

IronTerp

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A Failsafe occur when the engine performs much different than the TB and MAF data(other stuff too) indicate it should. Either over producing or under producing the expected torque, given a certain and load and airflow.
Bingo. I fought a Failsafe issue for a full year. Would occur at 3,000rpm with aggressive throttle. Tried every suggestion mentioned in this post. The issue was over production of torque and was remedied by an adjustment in my tune.
 

nxhappy

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run the lights and AC and test voltage ....report back
 

Joewee500

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It is possible that the colder air air is causing a table to be maxed out, and causing the failsafe(since the car is making more power with the denser air). I live in upstate NY, and a tune can be weather/temp sensitive(if it's off). Has your tuner had any feedback on the issue?

My car has been through the ringer. Tuned in Connecticut a few years ago. Brought to Louisiana Failsafing off and on with a Kenne be. Swapped to the tvs in Jan 2 years ago and had tuner send a file. Loaded it and revised it all in cold weather. There has literally been nothing performance related done to the car. Tuner doesn't think it's tune related. If someone wants to look at a log that captures it post email and I will send.


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me32

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My car has been through the ringer. Tuned in Connecticut a few years ago. Brought to Louisiana Failsafing off and on with a Kenne be. Swapped to the tvs in Jan 2 years ago and had tuner send a file. Loaded it and revised it all in cold weather. There has literally been nothing performance related done to the car. Tuner doesn't think it's tune related. If someone wants to look at a log that captures it post email and I will send.


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If tuner does not think its tune related what does he think it is?
 

me32

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First thing he said was throttle body. I spoke to vmp and they said they had only had 1 other instance of a failure and it was from water under hood. Mine has never been in the rain. Guess that would be my luck though.


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Is it possible for you to get your hands on another throttle body to test it?
 

Joewee500

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Just logged the car sitting still with some revs to try and Failsafe it without moving. And I made it happen. Logs look Greek except one thing that stands out. Torque Source says 11 when it failsafed and stayed there. Does it mean anything?


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moncho

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OP you've been given great information thus far...specifically about the TB and torque. You now pulled a datalog and torque comes up again. From what I've read so far on this thread is there's a good possibility that this is tune and/or TB related. If I'm not getting the help from my tuner it would be time for me to cut my loses & go elsewhere. Just implying this as you may have all the confidence in the world of your current tuner.

Don't give up, stay with it & you'll get it sorted out.

Bingo. I fought a Failsafe issue for a full year. Would occur at 3,000rpm with aggressive throttle. Tried every suggestion mentioned in this post. The issue was over production of torque and was remedied by an adjustment in my tune.
 

IronTerp

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My original tuner, who I had been working with for three years and was/still am very confident in his abilities, did not not what was causing the failsafe and did not think it was tune related. I returned to a tuner who I had used in the past and he knew right away what it was and fixed it immediately.
 

Joewee500

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My original tuner, who I had been working with for three years and was/still am very confident in his abilities, did not not what was causing the failsafe and did not think it was tune related. I returned to a tuner who I had used in the past and he knew right away what it was and fixed it immediately.

So what was causing your Failsafe? This torque Source 11 in the log seems to show something throttle body related whether it's tune or mechanical.


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RIO RED SNAKE

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I'm going to say the throttle body is your issue. Bill Tuned my 07 GT500 and it had a twin 65 on it and it would fail safe in the exact same conditions at the top of 3rd or 4th whatever I let out after a pull and then fail safe.. put a stock known working good TB on it and never gave me an issue again.
 

Joewee500

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I'm going to say the throttle body is your issue. Bill Tuned my 07 GT500 and it had a twin 65 on it and it would fail safe in the exact same conditions at the top of 3rd or 4th whatever I let out after a pull and then fail safe.. put a stock known working good TB on it and never gave me an issue again.

Bills the man and I would never say it was his tune. I talked with him a bit and sent him the log. He told me not to buy a throttle body just yet. Gonna chip away at it starting with the torque Source 11 then go from there. I'm hoping it gets resolved soon.


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RIO RED SNAKE

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Bills the man and I would never say it was his tune. I talked with him a bit and sent him the log. He told me not to buy a throttle body just yet. Gonna chip away at it starting with the torque Source 11 then go from there. I'm hoping it gets resolved soon.


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Agreed, Bill is an excellent tuner and has tuned 8+ vehicles for me and never an issue. I was just stating Bill also tuned my 07 GT500 with similar mods and had the same problem on the highway with it. Keep us posted, goodluck.
 

69b302

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Torque source 11 is a result of the fail safe not the cause. IMO. Most likely the TB tolerances are a little off, in the colder weather, and the tune needs to compensate.
 

me32

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Torque source 11 is a result of the fail safe not the cause. IMO. Most likely the TB tolerances are a little off, in the colder weather, and the tune needs to compensate.
More then likely this.
 

Joewee500

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Torque source 11 is a result of the fail safe not the cause. IMO. Most likely the TB tolerances are a little off, in the colder weather, and the tune needs to compensate.

So if the tolerances are a little off, cold weather will exacerbate the issue? Tuner is looking into it so hopefully it'll get resolved soon. I have a track day Feb 10th I am trying to make. Thanks for the response.


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