923.4v6

I've seen where some say its better to tune openloop with a wb and run in openloop than to tune closedloop with a nb. Even if its true or not could one use a nb o2 hooked up to a digital multimeter and tune using it instead of a wb? And if one could use the meter to tune pe afr's also.

TraviZ

iTrader: (2)

go wideband, a narrowband is only good for basically telling if you are lean or rich but not by how much.

figure its accurate between 14-15:1 afr

wideband is good for something like 11-20:1 afr

923.4v6

so what your saying is that, say .450 volts is 14.7 and if it goes to .850 the .850 maybe 13.0 one time and 11.0 the next, using the nb?

Binder

Sorry for the hijack but kind of on the same topic.....
We all know that a big cam can cause a NB O2 to read wrong because of the unburned fuel- oxygen in the exhaust. Why doesn't the same thing happen to a WB?
Why doesn't the WB see that same oxygen and read false lean?

SpeedMetalT/A

To answer the original question the wideband would definitely be better to tune with. A narrow band isnt as precise for reading purposes the readings will jump all over.

???

iTrader: (5)

http://www.innovatemotorsports.com/f...ead.php?t=3127

923.4v6

ok thanks I didn't know that exhaust gas tempeture had an effect on a nb 02 readings.

Grim Reaper

A Narrow Band O2 Sensor was developed to be primarily a "Switching Device". This topic has been discussed numerous times in the past and if you look at some of the past articles, there is even a graph that clearly shows why a NBO2 is ONLY usefull as a "switching device". The graph shows a nearly flat line at the bottom then an abrupt spike to another flat line at the top....just like you would want with a "switch".

For keeping the engine at 14.7:1 (where it "switches around"), it does a reasonably good job of keeping the engine metered at this level with the OBD I computers. Remember, you are dealing with ECMs that were developed BEFORE the original Microsoft Windows was availabe. It's the equivalent of "old MS DOS".

Trying to use a NB O2 as a RELIABLE Air Fuel Measuring device just doesn't work...it was NEVER designed to be used as that. You can obtain fairly good "part throttle" driveablity by tuning around 128/128 but that is because you are tuning around what the NB O2 was designed...just remember that it is "old MS DOS" and that while you MAY have 128/128, you still may be "off".

A WB O2 is designed to be an Air Fuel Measuring device though it too has only a range for fuel measuring. But unless your engine is WAY out of tune (and that can happen), the WB O2 is adequate for the typical tuning ranges we work with.

Binder

Thanks for posting this link, it's very informitive. Though If I understand this post from that link....

This seems to contradict what we have all been told about O2 sensors measuring the oxygen content in the exhaust.
It seems that the O2 sensor mesures the flow of oxygen through the sensor and the direction of the flow. If this is true then a NB O2 should not be effected by unburned fuel in the exhaust from a large cam.....
I must be missing something.
Again sorry for the hijack. Could a moderator cut my question and posts out of this thread and start a new one?

TraviZ

iTrader: (2)

unburnt fuel probably ( im taking a guess here) in a way clogs the narrowband o2 sensor so it cant accurately read the o2 going by.

i dont have a real good answer, all iknow is to go ahead and spring the 200something odd dollars for the inovate lc-1 controller, you will be glad you did.

sgt473

I believe that unburned fuel do to incomplete combustion contains high O2. The High o2 in the exhaust tells the ECM to increase the commanded fuel thinking that the o2 sensor is seeing a lean condition, when if fact the engine is running rich. Allso a low speed miss caused by a faulty plug or wire can cause the o2 to read lean and hydro carbons to go up. That's what the emission book told me. hope it helps

Binder

I have two of them, thanks.

Ronny

iTrader: (1)

Quote: We all know that a big cam can cause a NB O2 to read wrong because of the unburned fuel- oxygen in the exhaust. Why doesn't the same thing happen to a WB?
Why doesn't the WB see that same oxygen and read false lean.

I believe a WB also will read false lean. However it does not affect fueling(assuming no feedback to ECU). Soo if one understands the effect of overlap-reversion with a large cam one can always tune based on that anticipation. Open loop idle comes to mind. Also exhaust appearance/odor can be examined. Same on plugs. Vacuum reads may be helpfull. I would think as the rpms come up it is less of an issue. I think I was seeing false lean on WB at idle in that I am commanded OL to 13.7 and I see 1.00 lambda(stoich) on WB. Exhaust clean. I dont think WB is 100% accurrate there. Once I get to cruise CL I see 1.00 lamda again which I believe is accurrate.

sgt473

I read that there is a relationship between temperature and the O2 sensor. This may have something to due with the idle reading. Might be because the rich idle mixture doesn't keep the exhaust hot enough to report the proper AFR. I think I saw it on Innovate forum.