Changing AFR during normal driving with Tunercat???
 

Do I use the %change to fuel/air vs.rpm at wot??? also about what should these be set at with my mods below?? The program I have has it set at 10.2 from 3600 to 6800...does this not make it very rich?? The lower the number, the leaner it is right? My problem is that it runs like crap during normal driving...i thought it was too rich by the way it was bucking and jumping, anway, thanks in advance for any help.

Re: Changing AFR during normal driving with Tunercat???
 

Also, when using the formula, what coolant temp number do you use to calculate the AFR? Do you just use the warmest assuming the car is at the warmest point when you are going wot? also, is there a formula for converting degrees C to F??

Re: Changing AFR during normal driving with Tunercat???
 

Also, would someone with the cc306 mind sending me a copy of your %chg to fuel/air ratio vs rpm at wot tables for comparison.. I think mine are way off and the way I calculated it, it seems to be very rich. These were changed drastically from stock...like 8%

Re: Changing AFR during normal driving with Tunercat???
 

I'm not sure I understand fully what you are seeking. I'll go with what I think you want. If you are trying to change AFR for NON WOT driving then you'd have to run an open loop tune. In closed loop normal operation, the PCM is using O2 sensor feedback to attempt to maintain stoichiometric A/F ratio (14.7-1). 10.2-1 is on the rich side and the smaller the number the richer (it is parts of air - parts of fuel, so 14.7-1 is 14.7 parts air, 1 part fuel).

Go ahead and shoot back with specific questions if you have them. I can't really suggest much for your tune. I'd find it too specific to your circumstances to just say "Use this number".

Re: Changing AFR during normal driving with Tunercat???
 

thats not entirely true, you can do it in closed loop aswell, what you have to do is identify at what area you want your A/F to be richer & check the MAF readings at those points, go aheads & change the readings to richer (higher numbers mean richer), then say in all other areas your blms are at 120 or so while where you made it richer is now hitting 140 to try to lean the mixture out, go ahead & set the MAX BLM control to 130 so that you still have more then enough room for proper correction in other areas while the selected areas are limited, this will make you run leaner cuz the pcm tries to go to 140 to richen the lean mixture while your max blm control is set to 130 so it can't compensate, you can set it up that way so you still have good stoichometric management in other areas.

Matt.

Re: Changing AFR during normal driving with Tunercat???
 

Well, when I say 10.2, that is the % that was set in the program...calculated out it is like 11.68 which is still rich. So if the %chg to fuel/air ratio vs rpm at wot doesn't make a difference, why is it change so drastically in a mail order tune?


Wile2k>>>Your assumption was correct. I am trying to lean it down at normal driving, not wide open throttle. I kinda put two different questions in one.

Re: Changing AFR during normal driving with Tunercat???
 

right now your running 11.6 to 1 according to bin file.

this is mine ti will get you to 13.0 to 1

coolant
94.1
73.8
57.0
39.5
36.7
34.4
27.3
26.6
23.0
5.1
5.1
5.1
7.8
20.3
25.0

rpm

13.7
12.9
11.3
10.2
7.8
7.8
7.8
7.8
7.8
7.8
7.8
7.8
7.8
7.8
7.8
9.8
10.5

Re: Changing AFR during normal driving with Tunercat???
 

Yeah, I had it at 11.68. Thanks, I will try those values and see what happens. I changed them today to 8.0 instead of 10.2....but I will try yours first. Thanks again.

Re: Changing AFR during normal driving with Tunercat???
 

That helped out alot...Now the only problem is it is popping at around 2000rpm. and around 54-58 MAP..is that too rich still??? Should I lean it out a little more? Or make any changes in the ve tables? It has a pretty strong smell while at idle, i'm assuming that is too rich right?

Re: Changing AFR during normal driving with Tunercat???
 

the running rich at idle is the cam overlap, thats when the intake and the exhaust valve are open at the same time and fresh air escapes out exhuast and hit the o2s sensor and then the pcm adds fuel. there is a way to stop the running rich at idle, but that takes extensive tunning.

Re: Changing AFR during normal driving with Tunercat???
 

so what do you think is going on with the popping??

Re: Changing AFR during normal driving with Tunercat???
 

I stopped running rich at idle, it took somewhat extensive tunning.