Wideband Question

[Pop'stang]

First off, I'm no expert when it comes to wideband gauges or any other gauges for that matter. So I finished the install of an AEM analog wideband and oil pressure gauge this weekend and I'm not sure that the wideband is acting like it should.

You can see on the video that the needle is constantly moving back and forth. At idle it moves slowly and at cruising speed it does the same but faster. Is that normal? If it is, what value am I suppose to read? I tought that at cruising speed the needle would settle on lets say 14.5 + / - a few tenths. Anyway I'm just asking to make sure tat it's all good.

Thanks,

Patrick




video: http://www.youtube.com/watch?v=lHqhH37LLMU

 

[G.T]

that doesn't look right... the AFR should hover between ~14 and ~15 while idle, and drop as you go into part throttle, then lean out (16+) as you lift off, then settle back to ~14-15

ideally it should hover around 14.7 while idle and not continually sweep like yours does.

i'd check the voltage from the wideband sensor and see if it's also fluctuating as drastically as the gauge is, which could suggest a bad sensor.. if not, then the gauge (or the wiring to the gauge) is to blame..

out of curiosity, where is your wideband AFR sensor mounted?

 

[dmhines]

It shold settle down while cruising under load. There is no load revving in neutral. Mine bounce around 15 at idle

 

[Pop'stang]

that doesn't look right... the AFR should hover between ~14 and ~15 while idle, and drop as you go into part throttle, then lean out (16+) as you lift off, then settle back to ~14-15

ideally it should hover around 14.7 while idle and not continually sweep like yours does.

i'd check the voltage from the wideband sensor and see if it's also fluctuating as drastically as the gauge is, which could suggest a bad sensor.. if not, then the gauge (or the wiring to the gauge) is to blame..

out of curiosity, where is your wideband AFR sensor mounted?

I installed it just before the cat on driver side.

 

[G.T]

that's where it should be... so yeah, i'd check the voltage reading on the sensor and go from there

 

[INTRUDER]

Also, check your ground for that gauge. If you shared a ground...
Try it with its own ground and power supply.

 

[Pop'stang]

G.T. How do I check the voltage on the sensor.

As it is the ground is taken at the bolt holding tha dash on the lower passenger side, next to the sjb. The gauge has a wire to a constant 12V and another to a switched 12V, both are taken at the sjb with a add a fuse.

 

[G.T]

i don't know the wiring diagram off the top of my head, but set your volt meter to 20V DC and try all the wires coming out of the sensor

i believe the correct wire should be reading ~2.35V while idle which equates to 14.7 AFR ( AFR = 10+(2*Voltage) )

Edit: if the wires coming from the sensor are red, black, white and blue.. check the white wire..... if not, then check them all one by one

 

[GB10]

If you have a datalogger or tuner then datalog your short term fuel trims at idle when the gauge is fluctuating like it is. Should be in the + to - 10% range ideally. There should also be a PID for O2 sensor voltage which will be a range of 0.1v - 0.9v with 0.45v being around 14.7 AFR. Just report your findings here so we know what is going on, but the AEM widebands have a slow refresh rate which means the gauge is slower to respond compared to other brands like Innovate.

 

[mrdeath2000]

if your gas is 10-15% ethanol, isn't the stoich closer to 14.07? I thought I read that somewhere on here...

 

[Pop'stang]

I will check voltages and try to datalog this week. Kind of loaded at work and home. I don't think that there's ethanol in the gas (91 octane) that i'm using. Thanks for your help guys, will report back as soon as I can. BTW when datalogging for short term fuel trims at idle, where do I specify that?

 

[01yellerCobra]

What datalogging software are you using? I use Livelink and it has a PID titled STFT. Ideally it'll be at 1.00, but it's going to flucuate. I shoot for 5%, but 10% is liveable.

 

[Pop'stang]

Well I did the rag test suggested by the AEM technician and although it didn't react at all to brake cleaner (don't know why), it did react to gasoline. No rag = full lean, rag + gasoline = full rich and maintained. That seems to rule out that the sensor is bad.

I tried connecting the gauge directly to the battery and that didn't change anything.

Then I decided to clean the MAF sensor. Looked clean to me but you never know. Then I dataloged the STFT PID and it was quite steady with a 0.99 average. The gauge is now more stable. I still get the random needle swing at cruising speed but I guess that it's normal (maybe not). If you guys have anymore suggestions, let me know. If not, well thanks for your guidance.

Patrick

 

[lito]

if your gas is 10-15% ethanol, isn't the stoich closer to 14.07? I thought I read that somewhere on here...

Yes but it would not change a thing in the WB readout.

What datalogging software are you using? I use Livelink and it has a PID titled STFT. Ideally it'll be at 1.00, but it's going to flucuate. I shoot for 5%, but 10% is liveable.

Once the correction is learned shorts will always work around 1.000. That would not tell anybody anything.