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Do These AFRs Sound Right?

Blasphemous

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Mods: TRD S/C, 2.85 Stealth Pulley, AFE II Intake, DTLT Headers, URD Catback Exhaust.

AFR Gauge (Innovate MTX-L) in passenger side header.

During WOT 9.8-10.2.

That seems very rich to me. Pretty much at sea level. 80* F.

During idle it's right around 14.7, so I don't think there's anything wrong with the gauge.
 

SgtBadA

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Does seem rich. Mine is around 12 under WOT
 

NHXRUNNER

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Mods: TRD S/C, 2.85 Stealth Pulley, AFE II Intake, DTLT Headers, URD Catback Exhaust.

AFR Gauge (Innovate MTX-L) in passenger side header.

During WOT 9.8-10.2.

That seems very rich to me. Pretty much at sea level. 80* F.

During idle it's right around 14.7, so I don't think there's anything wrong with the gauge.

Safe to assume you're running the TRD Reflash?
 

STONER-X

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Could mean you have a clogged cat or a restriction somewhere
 

Torspd

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More boost! Wooooooooo! Wire in a MAF Cal with Map sensor. That could work right? o_O
 

lamia2super

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Only time mine goes into the 9s which usually get fuel cut from the ucon is when I have a faulty o2 sensor. With sensor working I see high 10s at wot
 

Torspd

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Sounds like you have the normal reflash richness, to me. As long as it is making power and feels strong.

If you had and aftermarket adjustable FPR, you could lower the fuel pressure and during open loop, it would lean it out.
 

iniazy

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I have observed similar richness levels in my Toyota with stock ECU and stock engine, at WOT. It only goes down to around 10:1 very briefly. I think Toyota stock tune is quite rich at WOT, to make maximum possible power. Unless the problem is from AFR front sensors, maybe if you replace them with new ones you'd get better results.
 

justin13703

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I have observed similar richness levels in my Toyota with stock ECU and stock engine, at WOT. It only goes down to around 10:1 very briefly. I think Toyota stock tune is quite rich at WOT, to make maximum possible power. Unless the problem is from AFR front sensors, maybe if you replace them with new ones you'd get better results.

Running rich creates a loss of power. Running leaner creates more power but is less safe because it creates more heat.
 

STONER-X

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Would that only cause issues during WOT? AFRs are right on the money during idle and normal cruising.

I had an exhaust tip that I called my shut up tip because it was baffled and closed off to reduce the noise. ..

The truck would idle fine but during heavy acceleration it would show it was running richer than normal.. This was due to the tip holding back the extra exhaust in the pipe so it would stay at the sensor longer..

If your sensor is before the cats and mufflers then it is possible something might be clogged... There is two ways to check without scan tools... One involves a pressure gauge before the cat and then running it after the cat to check for back pressure. . The the other one involves taking the temperature before and after the cats to see how it is performing. .

You can YouTube the processes and get a better idea of how to do it..
 

iniazy

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Running rich creates a loss of power. Running leaner creates more power but is less safe because it creates more heat.

Well I have to disagree with you. The ideal AFR for gasoline internal combustion engine is 14.7:1, but when you accelerate hard, the ECU would add fuel for more richness, not lean out, to improve power delivery. Leaning out will save fuel but lose power.

In all cases, excessive richness or leanness will cost you power, but generally in order to improve power delivery the ECU enriches the mixture a bit.
 

justin13703

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Well I have to disagree with you. The ideal AFR for gasoline internal combustion engine is 14.7:1, but when you accelerate hard, the ECU would add fuel for more richness, not lean out, to improve power delivery. Leaning out will save fuel but lose power.

In all cases, excessive richness or leanness will cost you power, but generally in order to improve power delivery the ECU enriches the mixture a bit.

An AFR of 11-12 will create much more power than an afr of 9-10. More fuel does not equal more power. The reason an afr is at 14.7 under light load is because there is not going to be a problem of excessive heat causing knock/pre ignition. Under wot the afr will drop to 10-12, not to create more power, but to make the engine not come apart. A richer afr burns cooler and is less likely to create knock. A leaner afr (closer to 14.7) creates more power, but burns much hotter, increasing the possibility of knock to occur and destroy the motor. This is why at wot, the engine is not designed to run at 14.7.

As crazy as it sounds, a richer fuel mixture burns cooler and creates less power than a leaner fuel mixture. You said it yourself, 14.7 is the ideal air fuel mixture. The farther you get from it, in either direction, the less power it will make. The tradeoff for a rich afr is less power, but more safety.
 

iniazy

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I don't disagree with this. Actually it aligns with what I said. Going richer, from 14.7 down to 11-12 will increase power. But I did also say that excessive richness or leanness will cost power. 9-10 is excessive richness.
 

mdd

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I don't disagree with this. Actually it aligns with what I said. Going richer, from 14.7 down to 11-12 will increase power. But I did also say that excessive richness or leanness will cost power. 9-10 is excessive richness.

No, you will make more power during wot at 14.7 than you will at 11-12. The question to ask is if the juice is worth the squeeze. You may only make a little more power with that lean of a tune, but you will run dangerously close to trouble.

Ways you can get away with running leaner would be different fuel and timing maps. Ideally, 11-12 afr. (Depends on who you're talking to) will net the best and safest tune.

OP, did you do the fpr mod?
 

Blasphemous

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No, you will make more power during wot at 14.7 than you will at 11-12. The question to ask is if the juice is worth the squeeze. You may only make a little more power with that lean of a tune, but you will run dangerously close to trouble.

Ways you can get away with running leaner would be different fuel and timing maps. Ideally, 11-12 afr. (Depends on who you're talking to) will net the best and safest tune.

OP, did you do the fpr mod?

No I haven't. This is what I'm reading without the FPR mod.
 

justin13703

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No, you will make more power during wot at 14.7 than you will at 11-12. The question to ask is if the juice is worth the squeeze. You may only make a little more power with that lean of a tune, but you will run dangerously close to trouble.

Ways you can get away with running leaner would be different fuel and timing maps. Ideally, 11-12 afr. (Depends on who you're talking to) will net the best and safest tune.

OP, did you do the fpr mod?

Exactly, 14.7 will always yield the most possible power no matter what your throttle position is. 11-12 afr will not make more power than 14.7 at wot, but it will be safer. I'm glad you understand how it works lol
 
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