running l/t's without tune

1

#1stangFAN

New Member

Mar 30, 2009

106

0

0

Dec 27, 2009

#1

• Dec 27, 2009

• #1

Well im installing Longtubes and an o/r h-pipe in my car right now and bamachips said it would take at the most 3 buesiness days to send me my new tunes but i already have tunes from him for my cai and gears. So i was wondering since ill finish up the install tommrow would it be safe to run the car for a couple days without the right tune or is that a no go? I know ill flip a light because i have no cats but other then that would i have to worry about anything else?

 

gmantheman

Member

Dec 30, 2007

483

1

16

Escondido, CA

Dec 27, 2009

#2

• Dec 27, 2009

• #2

I believe your A/F will be off.

 

NastyStang113

New Member

Sep 12, 2008

1,567

1

0

Florida

Dec 28, 2009

#3

• Dec 28, 2009

• #3

No you will be fine to run it for a few days. It will throw a CEL but it'll be okay. It might run slightly leaner as in a few tenths of a point but it wont hurt anything.

 

Marc S

New Member

Jan 23, 2009

61

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0

Dec 28, 2009

#4

• Dec 28, 2009

• #4

I agree, it will be a little leaner but nothing to worry about. I checked my A/F before and after my L/T install.

 

E

echoinsilence

New Member

Jul 22, 2009

87

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denham springs, LA

Dec 31, 2009

#5

• Dec 31, 2009

• #5

just dont bash on the motor, and you'll be good, just like everyone else has already said lol

 

mustangford289

Founding Member

Sep 16, 2001

957

5

48

Florida

Dec 31, 2009

#6

• Dec 31, 2009

• #6

Long tubes

I was unable to drive my car after installing LT's before I put the tune in. It threw a code as soon as I tried to move and did not allow the engine to rev at all. Maybe these other guys have a different experience?

 

R

Rob72

New Member

Jan 2, 2010

83

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0

Jan 8, 2010

#7

• Jan 8, 2010

• #7

I was under the impression that the rear O2's just relayed to the ECM that the cats were working properly but had no effect on engine performance.

 

StonePony

New Member

Jan 10, 2006

218

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0

Jan 14, 2010

#8

• Jan 14, 2010

• #8

It is the front O2 sensors that cause the problems after a header install. You can turn off the rear O2s if you dont need to pass an ODBII emissions test. The fronts may throw a DTC for not being heated fast enough. That can be adjusted in the tune.

 

NastyStang113

New Member

Sep 12, 2008

1,567

1

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Florida

Jan 14, 2010

#9

• Jan 14, 2010

• #9

Rob72 said:

I was under the impression that the rear O2's just relayed to the ECM that the cats were working properly but had no effect on engine performance.

Click to expand...

That's correct. Longtubes in some cases can lean a motor out slightly but it's so minimal that unless you're tune is on the ragged edge you will not have a problem.