Oxygen Sensors

[Brodyj]

How do you know if your O2 sensor is good? I was playing with and old one and I added so much injector duration that the engine died and there was no signal change. And just to make sure, 1 volt is rich, 0 is lean, an .5 volt is stoic?

Brody

[Brodyj]

How do you know if your O2 sensor is good? I was playing with and old one and I added so much injector duration that the engine died and there was no signal change. And just to make sure, 1 volt is rich, 0 is lean, an .5 volt is stoic?

Brody

[karter]

The oxygen sensor has to be hot to work. You have the voltages in the correct direction but, I think stoicometric is closer to .32 volts.

[B Lewis @ PE Engine Management]

Follow the steps below. This is a procedure outlined by Rick Kirchhof of Austin, Texas. I have found it to be very useful for determinig faulty O2 sensors.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Use a high impedence DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems. ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph. <HR></BLOCKQUOTE>

Brian Lewis
Performance Electronics, Ltd.
www.pe-ltd.com (http://www.pe-ltd.com)
"Complete Engine Management Systems for $798"

[Brodyj]

Thanks, I will try as soon as I get some propane.

[Scott M.]

I think I know the answer to this question, but here it goes...
How many people here are using a "std" 1,2,3,or 4 wire O2 sensor for fuel map tuning?
Just want to keep you reminded of the fact that these sensors are not useful for values other than right around Stoic or ~14.5 A/F. Anyone that is running those kinds of numbers isn't going very fast. Fuel economy is good though.

The only way to go is a UEGO sensor. The price can be prohibitive for some, but is truly the only way to get the fuel right. AEM has stand alone amplifiers (for reading directly into the ECU), as well as a gauge type with the amplifier built in.
Check them out here: AEM UEGO (http://aempower.com/product_ems.asp)

Email me for more info.

Scott
Superior Engine Technology
Exclusive Supplier of AEM to FSAE
Penn State FSAE 94-96
SuperiorEngineTechnology@yahoo.com

[This message was edited by Scott M. on February 17, 2004 at 09:06 PM.]

[awhittle]

http://www.innovatemotorsports.com/

[Brodyj]

I heard of these wonderful wideband O2 sensors that are suppose to be the cats meow as far as tuning goes. The way it was descried to me over forums, internet sites and the Haltech manual is that you would have to be crazy using a standard 4 wire 02 sensor to tune. I did a little research and found the cheapest way to go is a do-it-yourself kit from Tech Edge called the WB02. http://wbo2.com/ For a total of $166, you get a kit that you can have your EEs build that data logs to your laptop or palm. It also has thermo couple inputs, rpm inputs and generic voltage inputs. It took till yesterday for the EEs to finish it, so I have not had a chance to test it, but I will let you know.

On an other note: I have been tuning the whole time with a 4 wire O2 sensor and engine dyno, and I question the need for a wide band when tuning for max power. I found a top secret magic number that equals max power on the dyno every time. If you send a fresh Haltech E6X I will tell you. (WE fried ours when we did not connect it while welding on the header.)


Mr Peepers

[osubeaver]

http://fsae.com/groupee_common/emoticons/icon_smile.gif

[B Lewis @ PE Engine Management]

It is important to note that tuning using a wide band O2 sensor WILL NOT automatically give you the best fuel map. When using a dyno to tune for max performance, data from the wide band does not determine the final fuel numbers - the max torque at each load site does. The wide band is great for getting your mixture in the ballpark, but final tuning depends on crank output. You can get the same results using a narrow band.

Brian Lewis
Performance Electronics, Ltd.
www.pe-ltd.com (http://www.pe-ltd.com)
"Complete Engine Management Systems for $798"

[Jon Prevost]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Brodyj:
I heard of these wonderful wideband O2 sensors that are suppose to be the cats meow as far as tuning goes. The way it was descried to me over forums, internet sites and the Haltech manual is that you would have to be crazy using a standard 4 wire 02 sensor to tune. I did a little research and found the cheapest way to go is a do-it-yourself kit from Tech Edge called the WB02. http://wbo2.com/ For a total of $166, you get a kit that you can have your EEs build that data logs to your laptop or palm. It also has thermo couple inputs, rpm inputs and generic voltage inputs. It took till yesterday for the EEs to finish it, so I have not had a chance to test it, but I will let you know.

On an other note: I have been tuning the whole time with a 4 wire O2 sensor and engine dyno, and I question the need for a wide band when tuning for max power. I found a top secret magic number that equals max power on the dyno every time. If you send a fresh Haltech E6X I will tell you. (WE fried ours when we did not connect it while welding on the header.)


Mr Peepers<HR></BLOCKQUOTE>
Those Tech Edge guys stole the idea from a select few of "unengineers". My friends had designed the circuit a while back as a DIYer project. For them they learned what was going on. Just a heads up on them for reference to what I'm about to tell you. There kits are junk. Literally junk. I'm not just making this up. Read there mailing lists, it's amazing how cheap they are and how far then went to try and make it look different than the DIYer kit http://www.diy-wb.com/ . What makes them junk; electrical paths too small and running parallel to power supply line. Then there is the usage of cheap parts that are FAR from automotive grade. DO NOT put your circuit near heat or use a fan. There is more but those are the most serious problems. If I were to buy a kit it would definatly be the Innovative product.
Also, for anybody curious, OSU came in second on the dyno last year at competition and came in first place using a DIYer kit with slight modifications.
A wideband is worth it's weight in gold if you have to get your tune done quickly. It'll more than make up for it's price in time saved.
Good luck to all!

, Jon
"Success - it 's what
you do with what you've got." - Woody Hayes
Engine Team

[Scott M.]

Quote from Brian "You can get the same results using a narrow band."

There is no way you can get the same results with a narrow band... unless your peak torque happens to be very close to stoich (~14.6 a/f for gasoline). I don't know of many engines that make peak torque there.
The reason a narrow band will not work anywhere else but stoic is that is what they are designed for. Catalytic converters are most efficient at stoic so that is where road cars try to run as much as possible. It is interesting to note that many of the OEM's are looking at UEGO's. If you can keep the emissions under control they are very good for controlling a lean burn (direct injection gas, or diesel) engine. Honda used a UEGO on a production lean burn civic many years ago.

Brian is right about the way you use the sensor. You tune for peak torque at WOT. It doesn't make much difference what that number is, but it is nice if it is consistent. If it is consistent you can set up your target A/F map and use feedback or automapping to get your fuel map set up. The problem comes in when you move from the dyno to the car. How differnt are your EGT's at a given map point? Or more specifically how differnt is the temperature of the O2 sensor element? If you are tuning on the dyno using a steady state technique, then I would bet it is different. How much? Well, that is the point. Unless you are running a thermocupled senor, nobody knows. How diffent does the A/F read...?

Beware that all of the DIY and many of the commercially avaiable UEGO's do not use a calibrated sensor. If you don't have a dyno and are relying on accurate A/F numbers to get you in the ballpark, you will be mislead.

AEM talks about the narrow band senosr in their UEGO manual. I think it summarizes it well. It also has a graph demonsrating the effect of temperature on a narrow band.
AEM UEGO (http://forum.aempower.com/bbs/download.php?id=1643)

Scott
Superior Engine Technology
Exclusive Supplier of AEM to FSAE
Penn State FSAE 94-96

[B Lewis @ PE Engine Management]

Hold on there Scott, you must have misunderstood.

I agree there is no way that a narrow band will give you the same results as a wide band O2 sensor. There is no comparison between the two devices in terms of measuring range and accuracy. What I meant by that statement was that with a narrow band sensor and a dyno, you could tune an engine to make just as much power as someone using a wide band sensor and a dyno. The wide band may just save you some time, especially if you are new to the tuning process.

Brian Lewis
Performance Electronics, Ltd.
www.pe-ltd.com (http://www.pe-ltd.com)
"Complete Engine Management Systems for $798"

[Scott M.]

Yes, I agree if you have a dyno you can make as much power. You really don't need an O2 sensor at all...

You are right it is a great time saver. I would say that is true if you are experienced or not in tuning.

I think many FSAE guys get into trouble because they don't have a dyno/time/knowledge to tune the engine when the car finally gets driveable. This is a situation where a UEGO could keep guys out of trouble while they get the car/engine running the first time.

I should mention that a UEGO is a very good tool for tuning for driveability as well. It is one thing to get steady state sorted on the dyno, but is something else to get good driveability/transient control in the vehicle. A lot of time can be saved if A/F information is logged and reviewed so that direction and magnitude is known instantly. Experience is important here because of various transport delays depending on operating conditions.

Anyway... I agree that UEGO or narrow band. No difference on power output if you have the luxury of a dyno... http://fsae.com/groupee_common/emoticons/icon_smile.gif

Scott
Superior Engine Technology
Exclusive Supplier of AEM to FSAE
Penn State FSAE 94-96

[Marc Jaxa-Rozen]

Just curious, was it the Civic VX that had a UEGO? I think I remember reading that the Techedge unit used the same sensor.

Marc
ENA

[flybywire]

Off of the top of my head I think it was. Whichever got the VTEC-E (ie "lean burn") engine. I guess the Coupe HX must use the same sensor too. I think the explination was they have to use it because they run out-of-band for standard EGOs. Makes sense to me anyway.