AFR change at idle - Mustang Evolution

Go Back   Mustang Evolution > 1979-2015 Mustang GT || Tech and Talk > 2011-2014 Mustang GT



Reply
 
Thread Tools Search this Thread
Please support our sponsors and let them know you heard about them here!
Old 01-29-2016, 11:07 PM   #1
Registered Member
Regular
 
ILLY's Avatar
 
Join Date: Mar 2014
Posts: 100
AFR change at idle

I've notice that at idle after the car has warmed up the air fuel ratio moves from 13.5 to 15.5. The rpm drops and comes back up too. The rpm moves probably between 550-800. Feel like the car is about to die.

Car has the following mods; boss302 intake, jlt Cai, long tube headers with off road x pipe, tuned by AED. I installed all these mods at the same time. Didn't have this problem before when it was stock.

The car has a normal tune, not the ghost cam tune. Any suggestions are appreciated.


Sent from my iPhone using Mustang Evolution
ILLY is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 01-30-2016, 07:46 AM   #2
Registered Member
Regular
 
Robostang's Avatar
 
Join Date: May 2015
Location: Cheshire
Region: Connecticut
Posts: 621
Since it started when you installed the mods, I would check the intake and CAI installation. A vacuum/air leak in those areas could cause that problem.
__________________
2012 Kona Blue GT Premium 401A, Manual, 3.55, Steeda Pro-Action Shocks, Struts, Sport Springs, LCAs, Adjustable Swaybars, Adjustable Panhard Bar, BMR Relocation Brackets and Adjustable UCA, Driveshaft Shop Aluminum Drive Shaft, Airaid CAI, MGW Shifter, GT500 Axle-Backs, 3M Clear Bra and Tint, Side Window Louvers, JLT Oil Separator, Staggered MMD Zeven Wheels and Mickey Thompson Street Comp Tires, Bama 93 Race Tune
Robostang is offline   Reply With Quote
Old 01-30-2016, 08:18 AM   #3
Registered Member
Regular
 
DallasStang77's Avatar
 
Join Date: Sep 2013
Location: Dallas
Region: Texas
Posts: 1,842
Yup probably a vacuum leak. When I installed the Boss manifold my mustang, the intake pipe was loose cuz as I was tightening it the coupling slipped off because it was not seated properly and was angled off. So when the engine started I guess it popped off.

Rough idle. I set it right and it was normal. Doubt it's the tune but you never know. They might have missed something.

1.) Check all points for vacuum leaks
2.) If still rough do a data log without WOT and very light normal driving and send it to tuner

Good luck


Sent from my iPhone using Mustang Evolution
DallasStang77 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 01-30-2016, 09:18 AM   #4
Registered Member
Regular
 
Join Date: Dec 2011
Region: Canada
Posts: 2,974
Very likely post MAF vac leak, either in the intake pipe, tb or in the manifold install. A quick datalog of STFT will confirm this. These cars will still run with quite considerable leakage. The leaks can be tricky to find sometime bc of this. On an old car you could just propane the joints and get an immediate idle bump when you hit the leak. Not as easy with a fully closed loop modern car
__________________
2014 Premium GT, SGM, Brembo, Auto, Tech, Comfort, etc. GT500s, Steeda UCA, VMP auto N/A tune. 100 shot nitrous on BBR tune. Best e/t 11.42 at 120.64

2012 Premium GT, Candy Red, Brembo package, 3.73, MT82, Comfort, Tech, et al. Procal tune, Roush UCA, UMI poly LCA, GT500s, Steeda red bracket, Hoosier 28x10x16 bias drags. Best e/t 11.91 at 115.23 RIP
5LHO is offline   Reply With Quote
Old 01-30-2016, 11:19 AM   #5
Registered Member
Regular
 
utm18's Avatar
 
Join Date: May 2014
Location: trenton
Region: Ohio
Posts: 267
Send Shaun some datalogs.
utm18 is offline   Reply With Quote
Old 01-30-2016, 11:59 AM   #6
Registered Member
Regular
 
ILLY's Avatar
 
Join Date: Mar 2014
Posts: 100
I did send Shaun a datalog and he said that I might have an issue with the Evap system because the fuel at idle changes by 14%. I'll check again for vacuum leaks.


Sent from my iPhone using Mustang Evolution
ILLY is offline   Reply With Quote
Reply

Lower Navigation
Go Back   Mustang Evolution > 1979-2015 Mustang GT || Tech and Talk > 2011-2014 Mustang GT

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
AFR's on the way what's everyone's favorite intake? JayKranz 1979-1995 Mustang GT 82 10-14-2012 07:09 PM
Where are afr heads casted at 2300turboford General Car Discussion 0 10-13-2012 03:09 PM
Afr heads, pushrod & rocker arm requirements Fischerwilson 1979-1995 Mustang GT 2 10-01-2012 07:55 AM
AFR 165s captain78 1979-1995 Mustang GT 34 05-09-2012 03:17 PM
Windsor sr (ported) vs afr 185s 93stroker331 1979-1995 Mustang GT 17 06-03-2011 07:57 PM

» Like Us On Facebook



12:52 AM


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0

MustangEvolution.com is in no way associated with or endorsed by Ford Motor Company.