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Discussion Starter · #1 ·
I purchased a 2014 gt that was tuned by Lund but was not able to get the tune device. Lund informed me that the car was tuned for pump 91-93 and e85 with CAI K&N and LU-47 injectors , the car is catless long tubed as well. the cars afr is usually pegged at 10:1 afr, when i left off it shoots to 20:1, then back to 10:1 when i regain acceleration. I’m currently running pump 93 and the afr is on 10:1 what is wrong?
 

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2014 GT, 1967 Fairlane GTA
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The fuel injectors are way too large for the car, are completely unnecessary, and in fact have absolutely no benefit at all. Only detriments are possible with very oversized injectors on a mostly stock engine. The 2011-17 GT should have 34lb/hr injectors. In comparison, the forced induction GT500 used 47lb/hr. There's a reason that Ford didn't just put 47lb/hr ones on everything. Your HP dictates your injector size. Maybe the previous owner had no idea on how to correctly modify a car or he was planning on supercharging his car but injectors should only be done at or after the time of SC installation and not beforehand if the engine didn't need them and yours absolutely doesn't.
Mustang Stock Fuel Injector Size Chart - LMR.com
Your catless exhaust is also a major contributing reason as to why you're experiencing air/fuel issues. You should buy a quality catted midpipe(need the same brand as the long tubes to be compatible) and this will help you maintain a normal running car that doesn't overly consume gas. You'll need to buy a tuner to keep the long tubes on the car so you can get a tune to be compatible and legally compliant.
Btw, tuners aren't going to give you any new or further tuning adjustments when there's a catless exhaust so though Lund told you the tune that's in the car they or any other tuning company won't be supplying you with what's now a highly illegal catless tune. You should ditch the catless midpipe and 47lb/hr injectors.
 

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the cars afr is usually pegged at 10:1 afr, when i left off it shoots to 20:1, then back to 10:1 when i regain acceleration.
Completely Normal Performance Tune… The injectors are larger capacity to accommodate the E85 request from the PO.
 

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2014 GT, 1967 Fairlane GTA
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Completely Normal Performance Tune… The injectors are larger capacity to accommodate the E85 request from the PO.
I actually missed the mention of E85 in the OP's post.
Unless pretty much always running E85 I'm not sure the bigger injectors are worth having for an occasional E85 fill up. You can manually switch from a 93 octane tune to an E85 tune whenever you gas up but there is no sensor to determine the amount of alcohol in the gas as the PCM in Mustangs have no way of distinguishing between normal E10 and E85 on their own.
 

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I say this laughingly with a smile....reminds me of when I was in high school and one of the guys had a camero (327 IIRR) and dropped a 750 double pumper carb on that stock engine and was going to "blow my doors off!" Not that you can't make a carb like that run, but out of the box....... in the words of Star Trek Mr. Sulu.... "Ohhh My"..... there was more unburned fuel coming out of his exhaust pipe that what was burned in the engine!
 

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i’m running pump fuel and the afr is 10:1 that’s not normal
Not normal for a car running properly sized injectors and not trying to accommodate E85. From reading your posts above, you indicate it only goes 10:1 under acceleration. Often, aftermarket tuners intentionally run the AFR on the rich side for various reasons. It’s a compromise not necessarily optimal. If it’s a poor fit for you, or you feel there is another issue, get the car retuned, and start over. Since it’s a Lund tune, call Lund and ask why his tune goes to 10:1 on your car. It’s almost certainly wasting tons of fuel due to E85 adaptability.
 

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That’s completely normal… doesn’t distinguish what gas is being used just parts fuel to air ratio. Put in a vacuum gauge, does same identical thing- monitors manifold vacuum. Done with this one!
 
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