What is Lambda?

[4g63telantra]

I seen a few wideband that shows AFR or lambda

just want to know what it is?

 

[olmytsi]

Lambda is the measure the wideband uses. And then you can choose to have it display afr's for you since it's more practical.
Most widebands can display both.

 

[turbo8765]

Lambda simply refers to the o2 sensor. I believe the term originates from Bosch. If you read books on fuel systems they'll refer to lamda sensor, lambda sensor voltage etc etc

 

[DGajre777]

Lambda is volts, AFR is the air/fuel ratio. For example on the Zeitronix unit Lambda is 1.43 to 0.64 Wideband and AFR is 21.0 to 9.5 Wideband.

 

[blueman803]

Lambda is the reference to Stoich. Stoich values are different for different kinds of fuel. Lambda is a ratio of the afr ratio to stoich. The advantage to using lambda is it always gives the relationship to stoich. But most people don't think in lambda values and its a lot easier to read 12:1 and interpret that as rich.

 

[Apeximprt2nr]

Blueman is right.
Lamda is a ratio that refers to your current A/F Ratio and stoich of that fuel.
For gasoline the Stoichiometric measurement is 14.7:1.
So for example If you're running 12.6 A/F Ratio on gasoline, then your Lambda would be 0.86.
To figure that out, you multiply your lambda ratio (0.86) *times* 14.7 (stoich) to get your A/F Ratio.
Or if you're seeing your A/FR and you want to see what Lambda you're running you would divide your current AFR into stoich. (12.6 / 14.7 = .86)
So if you were running exactly 14.7 A/FR that means you're running 1.0 Lambda.
It's just like a test in school. You get a 86% on your test. That means you got 86% out of a 100% possibility.
Same thing with Lambda. You have .86 lambda. That's 86% of your possible 14.7 AFR. (12.6)
It's just another unit to refer to. It's like MPH and KmH. You're still measuring speed just in different way.
To really understand it, watch the video on here that says Tuning Basics, Theory, and Applications.
http://www.innovatemotorsports.com/resources/lm101.php

 

[Echo5Zulu]

Blueman is right.
Lamda is a ratio that refers to your current A/F Ratio and stoich of that fuel.
For gasoline the Stoichiometric measurement is 14.7:1.
So for example If you're running 12.6 A/F Ratio on gasoline, then your Lambda would be 0.86.
To figure that out, you multiply your lambda ratio (0.86) *times* 14.7 (stoich) to get your A/F Ratio.
Or if you're seeing your A/FR and you want to see what Lambda you're running you would divide your current AFR into stoich. (12.6 / 14.7 = .86)
So if you were running exactly 14.7 A/FR that means you're running 1.0 Lambda.
It's just like a test in school. You get a 86% on your test. That means you got 86% out of a 100% possibility.
Same thing with Lambda. You have .86 lambda. That's 86% of your possible 14.7 AFR. (12.6)
It's just another unit to refer to. It's like MPH and KmH. You're still measuring speed just in different way.
To really understand it, watch the video on here that says Tuning Basics, Theory, and Applications.
http://www.innovatemotorsports.com/resources/lm101.php

Kind of old thread but if anyone knows please chime in. Using the Lamda theory am I correct in saying; anything below 1.00 is lean and above 1.00 is rich? So .52 would be lean?

Reason I ask is my friends car is jacked up and Im helping him out. He's blowing black smoke and his plugs read real rich, but his innovative widband reads like .35-.53 or so.??? I do a lot of tuning with my car but its on the stock narrowband o2 so its just by 0-1 volts. I think he may have messed up his maft translator connections when he moved it because since he moved it changing the settings on it doesnt make a difference in his car. Also if the wideband o2 sensor is fouled out with soot would it prevent it from reading correctly??? Or does it need calibration??

 

[cdndsm]

It would actually be the opposite.
Anything below 1.00 would be richer then 14.7:1
Anything above would be lean.

So at 0.53 Lambda your A/F would be around 7.7:1
If the readings are accurate I'd say your running a TAD bit rich.

 

[spyderturbo007]

Kind of old thread but if anyone knows please chime in. Using the Lamda theory am I correct in saying; anything below 1.00 is lean and above 1.00 is rich? So .52 would be lean?

You have it backwards.

0.52 * 14.7 = 7.64:1 AFR

Holy crap that's rich.

EDIT -> Crap, cdndsm beat me to it. I have to learn to type faster.

 

[Echo5Zulu]

It would actually be the opposite.
Anything below 1.00 would be richer then 14.7:1
Anything above would be lean.

So at 0.53 Lambda your A/F would be around 7.7:1
If the readings are accurate I'd say your running a TAD bit rich.

Thank you for clearing that up. I had it the other way around in my head since Im used to tuning on narrow band (which is crappy I know) that also matches the rich mix comming from the exhaust. Thanks.

 

[Echo5Zulu]

You have it backwards.

0.52 * 14.7 = 7.64:1 AFR

Holy crap that's rich.

EDIT -> Crap, cdndsm beat me to it. I have to learn to type faster.

Better late than never. If his maf translator isnt connected right would it run fat rich? The translator trouble shooting blinking led said hes not getting a maf signal and the only way to run the car is to drop fuel pressure to like 20lbs. What do you think?

 

[spyderturbo007]

I've never used a MAF translator, so I'm going to have to let someone else handle that part. But I know if the ECU isn't getting a useable airflow signal, it isn't going to be your friend anymore. It will drop you into limp mode and run pig rich to protect the motor. Do you have a CEL?

 

[Echo5Zulu]

I've never used a MAF translator, so I'm going to have to let someone else handle that part. But I know if the ECU isn't getting a useable airflow signal, it isn't going to be your friend anymore. It will drop you into limp mode and run pig rich to protect the motor. Do you have a CEL?[/QUOTE

When I first checked for cels there werent any but I'll check again (I have to use my diagnostic computer his bulb is unplugged due to a 2nd o2 elimination). It does sound like its in limp mode though. We'll recheck all the wireing. Sounds like the translator isnt talking to the ecu properly, or the maf isnt talking to the translator. Thanks.

 

[spyderturbo007]

When I first checked for cels there werent any but I'll check again (I have to use my diagnostic computer his bulb is unplugged due to a 2nd o2 elimination). It does sound like its in limp mode though. We'll recheck all the wireing. Sounds like the translator isnt talking to the ecu properly, or the maf isnt talking to the translator. Thanks.

No problem.

Be sure to let us know how you make out.

 

[Echo5Zulu]

Update: Found a broken cold solder weld on the power wire to the maf so no power was getting to the maf therefore no signal out of the maf. Kind of a pain to diagnose since we had to test and track all the wires but she now purrs like a kitten. Now its time to tune. Thanks everyone.