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2015 Dodge Challenger RT Plus
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1 Posts
Discussion Starter · #1 ·
Hey Guys,
Ok, this is my first post.
I have a 2015 challenger rt plus shaker
*Borla XR-1 long tube headers
*Borla Atak cat-back exhaust system
*90mm BBK throttle body
*Diablo Trinity tuner
I just recently did a 274 comp cam install with upgraded valve springs and lifters.
Been working with Josh at HHP and he has sent me 3 tunes so far and car will not idle and stalls out. Was able to get it to run to let engine warm up and send Josh some better numbers from the log. It runs great between 2,000 and 2,500 rpms no hesitation at all. I can feather the gas pedal and keep it idling around 500 rpm until I let off and it dies. Sent Josh a data log and he seen that the car was running rich on bank 2 and lean on bank 1. He told me its something on my end and not the tune. He also mentioned I have good vacuum.
Things I've done so far......
Changed out all the spark plugs, O2 sensors for left downstream and left upstream, double checked all the push rods to see if one wasn't seated correctly. Has new exhaust manifold gaskets.
I did nothing with the fuel system components since I never touched that during the install. If I did have a bad injector prior to install would the new tunes from Josh be bringing the issue to light and now creating a problem?
I don't know where to turn except to check the injectors.

HELP ME!! Why is she running lean and not staying idling???
 

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18 Scat Pack Charger and a bunch of Mopar trucks
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7 Posts
I sway towards swapping your stock throttle body back on, too. Just to rule that out. I honestly never trust those BBK’s. They’re hit or miss if they work, man.
 

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18 Scat Pack Charger and a bunch of Mopar trucks
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7 Posts
In reality it should. But, it would also be hard to get much solid fuel trim data with it not wanting to idle at all. Josh is good. So it’s gotta be something simple-ish.

Ive had a bbk run me in circles before. So I’m a little distrusting on them acting normal.

If it were me, I’d definitely change that TB, if nothing else, just to rule that out.

And also check for any intake manifold leaks. It seems like it could be a leak.
 

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2015 Challenger R/T Plus 8 Speed
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8,497 Posts
Automatic or stick? I have the same cam with an A8 and the idle rpm was bumped up by OST.

Set the idle to 700 rpm, i do not have a stall yet. I use HP Tuners

Sent from my SM-G781U using Tapatalk
 

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2015 Challenger R/T Plus 8 Speed
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8,497 Posts
after that I would go back to the stock Throttle Body and see if that gets rid of the issues. I just noticed you run a 90mm, too big IMO, save it for when you add a supercharger.
 

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146 Posts
Back around 2014 I bought an 85mm BBK throttle body off a guy that took it off his 6.1 SRT, said it ran perfect. I installed it on my 5.7 to go along with JBA shorty headers and a 6.4 cam, I installed the year before. After the install the car had a real erratic idle and would stall if I let it idle more than 30 seconds and it was kicking a code for to much idle air. I took it back off and looked in at the throttle blade and noticed that with the throttle blade fully closed there was about a .002 gap between it and the bore. So I sent it out to a guy that repaired warn out T.B. he honed the bore out to 86mm and installed a new 86mm blade and sent it back , said he could not fined any thing else wrong. It has run perfect on the car for the last 6 years. I agree with the others here , put your original one back on and if it cures it send the other one back to BBK for a refund if you bought it new.
 

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Premium Member
2011 R/T 6M Bright White, 590whp 490wtq, Whipple 10psi, 274 cam, 1 7/8 LT headers, 429 gears
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1,297 Posts
Lean on one bank rich on the other leads me to a potential issue witn the intake gaskets.

Is Josh seeing major FTs on both banks indicating the fuel trim issues?

Do you have a WB AFR gauge?

Sent from my SM-T350 using Tapatalk
 

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235 Posts
Lean on one bank rich on the other leads me to a potential issue witn the intake gaskets.

Is Josh seeing major FTs on both banks indicating the fuel trim issues?

Do you have a WB AFR gauge?

Sent from my SM-T350 using Tapatalk
This. You have a gasket issue. Make sure all the intake gaskets are where they are supposed to be and retorque the intake. Check the exhaust gasket on that side and ensure all bolts are tight. Check the mid-pipe and ensure you have no leaks in the exhaust close to the O2 sensors.
 
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