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Discussion Starter · #1 ·
I got to experience the wonderful FailSafe mode the other day. I was switching tunes over from 93 to the 87 Economy tune on my SCT X3. I drove the car down to "0 miles till E" before putting in 87.

I fill her up about halfway, load the tune at the gas station and head out, as I'm going down the street the car jerks and goes into Failsafe. My first thought was that the gas left in the injectors and fuel lines was the 93 and threw the car for a loop.

After idling for a bit, and then reloading the tune, it still did it. I then went back into the SCT and found my problem. Apparently it wasn't the gas at all. The settings for the 87 Economy tune still had the stock airbox saved, not the C&L. My 93 performance and economy tunes both have the C&L Racer saved and since I haven't used the 87 since installing the CAI I forgot to update those settings. So needless to say, changed the airbox setting and reloaded the tune, good to go, no more failsafe.

I am curious though, does failsafe do any damage to the engine? I know it prevents damage, but does it cause issues? How long should you drive around in failsafe mode?
 

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Not a problem running 93 octane on a 87 octane tune. You just don't want it the other way around: don't run anything less than 93 octane on the 93 octane tune.

I'm guessing your PCM detected a too lean condition and went into limp home mode to protect your engine from damage.
 

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Not a problem running 93 octane on a 87 octane tune. You just don't want it the other way around: don't run anything less than 93 octane on the 93 octane tune.

I'm guessing your PCM detected a too lean condition and went into limp home mode to protect your engine from damage.
Totally right. You didn't have to run all the 93 out before you started the 87. The failsafe is just for that to keep damage from happening.
 

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Discussion Starter · #4 ·
Yeah, I figured out that it wasn't the octane at all, but the fact that the 87 tune thought I had the stock airbox still on and not my CAI, thus it flipped out.

I hadn't updated the 87 tune with the CAI when I got it. I was just curious if going into failsafe mode does any harm to the car.
 

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Can anyone help? I have a 2008 Mustang GT. Just got my performance kit today, which included BBK Titanium Air Intake Kit, with the 62mm Throtte Body and also came with the Weapon X Coil Pack kit, New Brisk Plugs and SCT F3 Flash Tuner. After installing each individual part, I started the car to make sure all was good. Got the wrench light once because I forgot to connect the MAF connector. After that it ran great.

My last step was installing my performance tune on my programmer. This is when all went to the toilet.

It made some weird **** happen. I got two codes out of it P2104 for throttle actuator control, and another P2111 for throttle actuator control stuck open.

Also something really weird is that my Tire Pressure Monitor Light and warning Chime is going off now.

So I put the tune back to stock. Disconnected both positive and negative battery cables and reinstalled all factory parts and it is now still in fail safe mode. Car won't go above 3 mph.

Any ideas?

Thanks for any help you can offer!!
 
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