HELP: AFR Going Super High

[MrClean]

Hey gang,

So I have quite the concern regarding the Cobb AP and maybe the Cobb guys will have an easy answer for this.

My first modification I had done to my Fiesta was the Cobb AP. Love it. Plugged it in and was set on Stage 1 for several months. Then, I nutted up and finally got around to installing my Cobb DP and FSwerks catback. The installation was smooth and everything sounds great.

My problem is, I downloaded the latest Stage 2 and Stage 3 maps and then set the AP to Stage 2 thinking that would be appropriate given my simple modifications. In my AP i have it set up to monitor Boost, AFR and engine temps. I started paying attention to my AFR values after noticing it was spiking to 40+ during around-the-town driving. Consider me concerned! That's so damn high!

At first, I thought this may simply be because the car might not be warmed up all the way, but I baby the car around anyway. Am I about to detonate my motor here or is the AP misreading my AFR values?

Any and all help is appreciated.

 

[iso100]

40+ is normal for coasting in gear. It's a fuel savings strategy.

 

[dyn085]

40+ is normal for coasting in gear. It's a fuel savings strategy.

^ Exactly this. You should see those readings any time you let off the accelerator and coast in-gear.

 

[DHM1]

Deceleration Fuel Cut Off.

 

[re-rx7]

Is this really a question? People that dont understand the basics of cars performance shouldnt be modding...

 

[DHM1]

Is this really a question? People that dont understand the basics of cars performance shouldnt be modding...

we all had to start some were i guess.

 

[re-rx7]

we all had to start some were i guess.

Yea with knowledge.

 

[Ronbo]

Knowledge is gained by asking questions.

 

[re-rx7]

Knowledge is gained by reading and understand basic operating priciples of AFR and DI engines.

 

[razorlab]

grumpy cat.

 

[RAAMaudio]

Anybody here just wake up and know this stuff?

Anybody here that knew all there is about modding from reading a book or two or a magazine article?

I have been modding cars for 46 years and can do most anything up to full race builds, ground up, but I just never got into tuning so still learning as I have to but trust others that know more and I ask lots of questions.

 

[rodmoe]

I Started out fixing it till it broke then rebuilding it faster !! I miss my 2 Stroke days and jetting them down till you meet MrSqueaky and go up one size lol
there are NO dumb questions yada yada yada ..

 

[fiestapowa]

Good question OP. Hopefully this will help others who may end up with the same concern.

 

[DHM1]

Anybody here just wake up and know this stuff?

Anybody here that knew all there is about modding from reading a book or two or a magazine article?

This and This

You have to learn from things you do and others do around you.

 

[COBB Tuning1]

Deceleration Fuel Cut Off.

This is correct and is done for emissions and fuel savings. 100% normal.

Cheers,
Braden @ COBB