AFR slightly rich, is okay ?

NewCivicRs

Senior Member
First Name
CIVIC.FK4
Joined
Mar 24, 2020
Threads
71
Messages
430
Reaction score
62
Location
Indonesia
Vehicle(s)
Civic 1.5 Turbo RS
Country flag
Hi @KTuner, is it okay to let it be running rich for long term?

During WOT Open Loop:
AFR around 9,5-10,2
AFR.CMD stay at 11.0

I get good gas mileage on eco mode driving, whenever I drive it like granny, the gas is very efficient.
During WOT, the power is ready from 2500 to 6000 RPM, tires lost traction, the power throws me back to the seat so hard, I can feel the power always there and strong even at high RPM,
The engine runs smooth, no knocking sound.

Leave it alone or adjust the AFR?
Sponsored

 
Last edited:

pumpkin

Senior Member
Joined
Oct 30, 2020
Threads
8
Messages
85
Reaction score
39
Location
Canada
Vehicle(s)
2018vic
Country flag
running rich long term will destroy your cat converter
 

Gruber

Senior Member
First Name
Mark
Joined
Jan 27, 2018
Threads
2
Messages
2,309
Reaction score
1,521
Location
TN
Vehicle(s)
2018 Honda Civic Sport Touring; 2009 Honda CR-V EX-L
Country flag
running rich long term will destroy your cat converter
In general, no. Burning excess fuel in the catalytic converter requires oxygen. The O2 sensor detects the mixtue as rich when it finds no oxygen and the wideband O2 sensor actually can go beyond that and sense how small the traces of oxygen really are to determine how rich it really is (to some extent).

When the engine works as it should, running rich means there is no oxygen left to burn because it wss alesdy all burned in the cylinders. So the excess fuel actually cools the cataltic converter.

But if there are misfires....or any other reason for incomplete burn, (of the air) the excess fuel + air mixture may reach the converter and burn there. But this will not even be detected as a rich condition by the wideband (because there is oxygen in the mixture).

So if your catalytic converter is not glowing red, or at least overheating, it's fine.:cool:
 
OP
OP
NewCivicRs

NewCivicRs

Senior Member
First Name
CIVIC.FK4
Joined
Mar 24, 2020
Threads
71
Messages
430
Reaction score
62
Location
Indonesia
Vehicle(s)
Civic 1.5 Turbo RS
Country flag
running rich long term will destroy your cat converter
I heard that running engine in lean will make it hot, which is true?

did you just flash it? It runs rich under boost for a little bit after a flash
Yes, about almost 3 weeks. I did datalogs 1 week after, now I have not done a new one yet.

In general, no. Burning excess fuel in the catalytic converter requires oxygen. The O2 sensor detects the mixtue as rich when it finds no oxygen and the wideband O2 sensor actually can go beyond that and sense how small the traces of oxygen really are to determine how rich it really is (to some extent).

When the engine works as it should, running rich means there is no oxygen left to burn because it wss alesdy all burned in the cylinders. So the excess fuel actually cools the cataltic converter.

But if there are misfires....or any other reason for incomplete burn, (of the air) the excess fuel + air mixture may reach the converter and burn there. But this will not even be detected as a rich condition by the wideband (because there is oxygen in the mixture).

So if your catalytic converter is not glowing red, or at least overheating, it's fine.:cool:
If I get what you mean, you say that the gas pass through the exhaust and it's cooling it because there small amount of unburn fuel?
 
Last edited:


OP
OP
NewCivicRs

NewCivicRs

Senior Member
First Name
CIVIC.FK4
Joined
Mar 24, 2020
Threads
71
Messages
430
Reaction score
62
Location
Indonesia
Vehicle(s)
Civic 1.5 Turbo RS
Country flag
People say that running rich will only rob small amount of power from what it actually can make..
But what I feel now is the power keeps coming from 3000-6000 RPM, it pushes me back so hard and tires lost traction, also the ECT and IAT2 not overheat.

I will do one more datalog.
 

gtman

Senior Member
First Name
Mitch
Joined
Oct 27, 2015
Threads
328
Messages
16,672
Reaction score
24,356
Location
USA
Website
www.civicx.com
Vehicle(s)
2017 Cosmic Blue EX-L Sedan
Vehicle Showcase
2
the power keeps coming from 3000-6000 RPM, it pushes me back so hard and tires lost traction, also the ECT and IAT2 not overheat.
All of which tells me you're doing OK.
 
OP
OP
NewCivicRs

NewCivicRs

Senior Member
First Name
CIVIC.FK4
Joined
Mar 24, 2020
Threads
71
Messages
430
Reaction score
62
Location
Indonesia
Vehicle(s)
Civic 1.5 Turbo RS
Country flag
All of which tells me you're doing OK.
Hi bro, I think so.
It is been a month since remapping.
I will do one more datalog to see how the AFR is doing.

As I remember, you have seen my datalog, right? You seen the AFR too rich, isn't it?
Sponsored

 


 


Top