07 Shelby Running Lean, Help Please

[07shellb]

Okay to start off, I am new to the forum so hi to everyone and I look forward to being a member. I have a little problem right now with a mustang I recently purchased. The car is an 07 shelby gt that was in an accident and I have fixed back now. The car would not start when I purchased but upon further inspection someone had a blowwer on the car previously and they had pulled the tune and not replaced with factory tune. The Shelbys as U all may know come with a more aggresive tune from the facory and when the dealership flashed mine they used the stock gt tune. All is well and car starts right up but is throwing the dreaded p0171 and p0174 lean on both banks codes. I cannot find any vacuum leaks and engine runs fine once over 2k rpm but when u mash the pedal at idle it ust hesitates and almost dies before catching itself. Would anyone know if the shelby upgrades would cause this much touble with the factory gt tune or my problem is elsewhere? Thanks and all help is appreciated

 

[SpartaPerformance]

Yea the Shelby comes with the FRPP cold air intake so a stock GT tune is not sufficient.

 

[07shellb]

thanks so much for the quick reply, so you do think that it would run that rough with the stock tune with the shelby upgrades? and if so, Will a handheld tuner compensate in place?

 

[jpplaw]

You need a handheld tuner with a tune for that type of CAI. The MAF sensor housing is larger (more air is going through) than a stock GT housing. Thats why the car is running lean; the stock GT tune is not compensating by adding fuel for the extra air.

 

[SpartaPerformance]

What I want to know is why the dealer would flash it with a GT tune, to me it sounds impossible because the IDS will flash the vehicle based on VIN

 

[07shellb]

Thanks for the help guys, Got my diablosport predator in yesterday, tuned it to the 90mm MAF and it runs like a champ now. Im still amazed how sensative these 3v's are but im just happy its fixed. Thanks again

 

[bigb427]

What I want to know is why the dealer would flash it with a GT tune, to me it sounds impossible because the IDS will flash the vehicle based on VIN

It's obvious the technician working on the car didn't know it had, and needed an aftermarket tune in it. Why they did it is anybody's guess.

That in itself is the problem. IDS automatically attempts to identify the vehicle based on the VIN, not what calibration file is programmed into it. When reprogramming a PCM with IDS it only looks for a more recent calibration file than what's in it currently. If the calibration file is an aftermarket one (as is the case on Shelby GT's, even though it was made by FRPP), or one that IDS does not recognize, it will simply program the PCM with the most current file available from Ford.

I have seen this problem on many occasions, each time the person working on the vehicle wasn't aware an aftermarket tune was present. I have seen this on a few Saleen and Roush vehicles.

 

[SpartaPerformance]

It's obvious the technician working on the car didn't know it had, and needed an aftermarket tune in it. Why they did it is anybody's guess.

That in itself is the problem. IDS automatically attempts to identify the vehicle based on the VIN, not what calibration file is programmed into it. When reprogramming a PCM with IDS it only looks for a more recent calibration file than what's in it currently. If the calibration file is an aftermarket one (as is the case on Shelby GT's, even though it was made by FRPP), or one that IDS does not recognize, it will simply program the PCM with the most current file available from Ford.

I have seen this problem on many occasions, each time the person working on the vehicle wasn't aware an aftermarket tune was present. I have seen this on a few Saleen and Roush vehicles.

Good point, a case of IDS brain fart and technician dumbassness.