A/F ratio question

yup i get the same thing what an A/F gauge does it searchs for stoich.. until you go WOT.... you get your real A/F Ratio reading at WOT.... mine does the same thing yours is doing!
 
I dont agree...unless I am misunderstanding your 70 & 75 MPH were staying in the 16s....TOO LEAN........your 45mph was slightly rich in the low 14s.......mine bounces between 14.3 to 15.5 at any speed other than WOT..
 
TNVIPER said:
I dont agree...unless I am misunderstanding your 70 & 75 MPH were staying in the 16s....TOO LEAN........your 45mph was slightly rich in the low 14s.......mine bounces between 14.3 to 15.5 at any speed other than WOT..

Your AFRs are right on the money.
He should listen to you about his.
Rich down low, leans out at higher RPMS.
 
TNVIPER said:
I dont agree...unless I am misunderstanding your 70 & 75 MPH were staying in the 16s....TOO LEAN........your 45mph was slightly rich in the low 14s.......mine bounces between 14.3 to 15.5 at any speed other than WOT..

Ditto!
 
Paul, what is it at WOT? That's really what you should be concerned with.
 
I am inbetween 13-14 on WOT. Should I send Roe a message to get a modified tune (this is his tune on the truck).

Thanks
 
amtrucker22 said:
I am inbetween 13-14 on WOT. Should I send Roe a message to get a modified tune (this is his tune on the truck).

Thanks

13-14 is lean...you should be mid/high 12s......but before you change tunes I would put it on a dyno to get a good reading. The guage you have is same as mine and they are fairly accurate but it is hard to follow a A/F reading while trying to drive at WOT.....your cruise A/Fs may be due to faulty O2 sensors..
 
paul find a stretch of hwy you can do a third gear roll the best ya can, watch the air/fuel meter, you should be in the 12's or less all the way to redline, anything more get yyour tune modified, cruise doesnt give load readings well, it gives you the accurate reading under full throttle
 
Stinker said:
paul find a stretch of hwy you can do a third gear roll the best ya can, watch the air/fuel meter, you should be in the 12's or less all the way to redline, anything more get yyour tune modified, cruise doesnt give load readings well, it gives you the accurate reading under full throttle
:withstupid: :D
 
amtrucker22 said:
Here is the WOT pull

WOT --> LINK
I dont know if its the camera or me jumping around a bit, but its def lean 14 anything at wot to me is a bit lean
I would get it richened up jsut a tad there bob:D
 
With Torrie's tune I'm around 11.8 - 12.1 at wide open throttle. It's either a tune issue. Or like TNVIPER was saying, maybe an oxygen sensor issue. Only wat to find out, is to get it on a dyno. But I wouldn't be doing any WOT runs unitl You find out for sure.
 
Guys I think most of your info is on par, but I want to add a couple things from my experiences. First off cruising A/F is fine to be around Stoich between high 13 and low 15 being 14.7 is stoich with the fuel we use. N/A vehicles I like to see around 12.5-13 WOT, just a little on the rich side. Idle should be around the Stoich mark as well. The idea of starting rich and ending lean is not quite true. The ECM has almost infinite tables and cells for correcting and tuning a certain spot in the rpm band. If it's a little rich at 5K you can lean it out some. If it's to lean at 5100 rpm you can adjust for that. You want to log the data and see how your ECm is reacting. Does it show knock retard anywhere through the pull? Timing can also be adjusted for each cell and if there is some kind of detonation it can be fattened up in that cell and surrounding cells to alleviate the problem.

The O2 sensors are not playing a part in tuning during WOT as you are running open loop during this time as in intitial startup. In other word it is using preset parameters at WOT vs correcting in closed loop via O2 sensors and other sensor readings. Your idle after warmup and cruising is handled closed loop and adjusted by the ECM. :D
 

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