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- - Air Fuel Ratio (https://www.toyota-4runner.org/3rd-gen-t4rs/220518-air-fuel-ratio.html)

GrassFed

06-03-2016 12:52 AM

Air Fuel Ratio

Short and simple, what do you guys run on average air fuel ratio wise. At idle I'm running at about 13.6-13.8.

Thanks in advance

SP2PILOT

06-03-2016 08:01 AM

A perfect AFR is 14.7:1, so 13.6-13.8 at idle is fine.

Rock_Rat

06-03-2016 08:34 AM

14.56

JRZEE2000TR4LTD

06-03-2016 08:42 AM

I believe our trucks always try to maintain perfect stoich which is 14.7. My scangauge confirms this. When you give it throttle it goes higher for a short period of time meaning it's running leaner (say in the 15-16:1 area, depending on how much throttle was given) because of the open throttle body butterfly allowing more air in but the ECU compensates by adding more fuel to the fire. Your numbers suggest you're running a little rich which would hurt fuel economy. If your truck is running like this in closed loop (warmed up) then you may have a problem.

GrassFed

06-03-2016 08:51 AM

Correct, those are the closed loop numbers. I'll get a better idea of my MPG once I calculate this tank. The gas gauge reallly isn't too much of a help because the thing drops like a rock. Appreciate the responses.

Rock rat, you're almost perfectly mixed there even with over 300k on the odo. Impressive

JayRolla

06-03-2016 09:20 AM

I ran a lean idle medium throttle on my DSM's to try and get better had mileage on e85. 16-16.5 afr. Didn't do much.

GrassFed

06-03-2016 04:33 PM

Thanks for the tid bit J. Looks like I might be ok. I am not sure what the problem would be if there is one anyway. Recently replaced my air fuel ratio sensor, plugs, wires and fuel filter so I figure I am at least close to optimal numbers unless I have something else throwing the numbers off

Rock rat reports almost perfect stoich numbers which makes me wonder

Rock_Rat

06-03-2016 05:26 PM

Quote:

Originally Posted by GrassFed (Post 2378063)

Take a look at my LAST video of the TRD Cat Back exhaust. I capture the Scan Gauge off-and-on but for the most part I hardly move away from 14.56 while cruising.

GrassFed

06-03-2016 06:25 PM

Rockrat that scenery is something else. Your numbers tell me I have something off causing my ecm to send too much fuel. I reckon your fuel economy is pretty good running that close to perfect? Even with your tires and gears.

I might need to start investigating this. I did pop my coil packs off and 2 of the 3 had corrosion on the terminal that the spark plug wire connects to.

Thank you for the time and responses guys

On a side note I wonder if there is some variance as I am using an app called torque as opposed to the scan gauge it looks like you're using

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