AFR accurate on Torque App?

[stevo585]

The AFR doesn't seem to be accurate for me. Its running 14.0 at cruise and down to mid 10's WOT (which the sensor cant even read that low). I know my tune is 11.8-12.0 WOT and of course 14.7 cruise.

Is there a more accurate PID you can manually create or some way to scale it?

[steve99]

Originally Posted by stevo585

The AFR doesn't seem to be accurate for me. Its running 14.0 at cruise and down to mid 10's WOT (which the sensor cant even read that low). I know my tune is 11.8-12.0 WOT and of course 14.7 cruise.

Is there a more accurate PID you can manually create or some way to scale it?

torque app should work fine,


are you using 02 sensor 1 bank 1


suspect you logging incorrect sensor


the update rate on torque can be a bit slow.

[stevo585]

Originally Posted by steve99

torque app should work fine,


are you using 02 sensor 1 bank 1


suspect you logging incorrect sensor


the update rate on torque can be a bit slow.

No I'm logging air fuel ratio (measured). Ill try the one you suggest. Thanks!

[Tectoniic]

Disclaimer: I've never used the torque app, I use OFT for logging so I'm just going off of that.

Are you sure you are not confusing AFR with Command AFR? Your ECU may want 12.0(Command AFR) at full throttle but you may actually be at a ~10.5(Measured AFR) or so if you have a problem with the tune or other issues.

[justatroll]

In my experience AFR is 'mostly useless' to watch real-time.
The only time I trust it is when I log it and look at averages.
I even have code that calculates a running average AND focuses on only when WOT.


Just a shift can throw mine briefly into the 20s and it can take time to settle out.
(disclaimer mine is an aftermarket Innovate sensor, not the one the ECU is reading).


However I did save my Porsche race motor on the track when the AFR was reading consistently in the 18s and I brought it in right away.
Saw one EGT drop by 800 degrees and knew exactly what jet to check (it was clogged)

[stevo585]

Originally Posted by Tectoniic

Disclaimer: I've never used the torque app, I use OFT for logging so I'm just going off of that.

Are you sure you are not confusing AFR with Command AFR? Your ECU may want 12.0(Command AFR) at full throttle but you may actually be at a ~10.5(Measured AFR) or so if you have a problem with the tune or other issues.

Torque and the OFT would use the same sensors. I'm logging measured and commanded gives me the same number. I'm custom tuned on ecutek. Nothing gives me any reason why my afr would be off. Car runs and feels fine. The fact that its "reading" 10.x tells me it off. Its not possible the stock sensor maxes around ~11.2.

[stevo585]

Originally Posted by steve99

torque app should work fine,


are you using 02 sensor 1 bank 1


suspect you logging incorrect sensor


the update rate on torque can be a bit slow.

I actually don't see what you mean. O2 sensor 1 bank 1 is not a choice in torque. I'm going to try to create my own PID using lamda. That does read 1.0 at cruise. So I figure if lambda*14.7 should be close.

[steve99]

Originally Posted by stevo585

I actually don't see what you mean. O2 sensor 1 bank 1 is not a choice in torque. I'm going to try to create my own PID using lamda. That does read 1.0 at cruise. So I figure if lambda*14.7 should be close.

suppose it depends which version of torque.


Im currently ecutek tune on E85 and the standard afr and commanded afr pids work fine in torque and match up with ecutek logging.


the stock front o2 sensor can be re-calibrated in tune to read down to around 10 AFR quite will.


you might want to confirm the reading with ecutek cable or another logging device

[guybo]

It depends on your fuel too. If your area has only E10 (like where I live) your AFR will be lower than straight gas. There's a way to figure that out. E10 will run about 14.11 stoich.

[Wayno]

Originally Posted by guybo

It depends on your fuel too. If your area has only E10 (like where I live) your AFR will be lower than straight gas. There's a way to figure that out. E10 will run about 14.11 stoich.

No it won't.

[guybo]

Actually- yes it will. Look it up. Ethanol burns differently than gas. I had an AFR gauge hooked up on my old car and I could tell how much gas/ethanol places locally used by the numbers.

http://www.ultra-gauge.com/customer_...php?article=29

Who'd a thunk it?

[steve99]

Originally Posted by guybo

Actually- yes it will. Look it up. Ethanol burns differently than gas. I had an AFR gauge hooked up on my old car and I could tell how much gas/ethanol places locally used by the numbers.

http://www.ultra-gauge.com/customer_...php?article=29

Who'd a thunk it?

What they say looks correct but it depends on how the ecu interprets the signal from the 02 sensor.

The 02 sensor reads lamda, it reads amount of residual oxygen in the exhaust gass, it does not know anything about afr.

The ecu get a signal from the 02 sensor aboit the residual oxygen, as a voltage or current reading this is converted by the ecu into an afr value by the ecu, have a look at the 02 sensor scaling table in ecu.

In our ecu its scaled to PETROL afr, and the ecu calculates everything reliative to petrol afr, these calculations are coded in the ecu program and not changeable by just changing tables

this is a rescaled table but for the exercise its ok

So the when your on 100% petrol the ecu calculated the amount of fuel to inject to get say lambda 1 (14.7 petrol afr) and all works fine and everything easy to understand.

When you run say full E85 and the ecu targets lamda 1(9.8 afr for e85) the 02 sensor doesnt know the difference as it reads lambda so it signals ecu lambda 1 and the ecu interprets this as 14.7 gasoline afr, but the ecu has to inject far more fuel to achieve this hence you need to alter the injector scalings to run e85 without huge fuel trims.

But when your on e85 the ecu or 02 sensor doesnt know it calculates everything same as it did for petrol, the afr tables are all still based on petrol afr and at stoic it will read 14.7 afr, even though the real afr is 9.8, as the ecu still thinks your running petrol.

When you run E10 fuel all that happens is your ltft, long term fuel trim will move slightly positive so ecu injects more fuel to keep the afr same as on straight petrol.

ive been on e85 for years and used torque and ecutek and tactrix and oft but they all read 14.7 cruising jist like petrol, jist the injector scaling is bumped up 30% to get the ecu to add the extra fuel without running 30% fuel trims.

[Wayno]

Originally Posted by guybo

Actually- yes it will. Look it up. Ethanol burns differently than gas. I had an AFR gauge hooked up on my old car and I could tell how much gas/ethanol places locally used by the numbers.

http://www.ultra-gauge.com/customer_...php?article=29

Who'd a thunk it?

So you are basing all your assumptions on a completely different and irrelevant platform. GG.

[guybo]

Don't post here on things you nothing about. Thanks for playing though.