What's Up With My A/f Guage

[blubyu21117]

i'm really confused on how to read the a/f guage.
it just bounces around constantly.
is this normal??
i know that it shouldn't be in stoich under boost, right??
it just seems to give a good light show and that's it.
(uhm)

 

[freekwonder]

are you using the stock O2 or do you have it connected to a wide band O2. connecting it to a stock o2 will give you the disco light show.

 

[blubyu21117]

yeah, it's connected to the stock o2 sensor.
they didn't tell me i would need a wideband.

 

[BremertonMSP]

i'm really confused on how to read the a/f guage.
it just bounces around constantly.
is this normal??
i know that it shouldn't be in stoich under boost, right??
it just seems to give a good light show and that's it.
(uhm)

At idle and normal driving, it will bounce around from lean to rich. Under WOT it should go full scale rich. When it in gear and you have your foot off the gas pedal while going coasting, it will read full lean.

 

[BinaryRotary]

I've mentioned this before in other threads, if you have the A/F gauge on the FIRST o2 sensor, it will bounce from lean to rich constantly. The first o2 sensor is the one that senses the 'mix' between air and fuel.

In order to get a better o2 reading you must connect it to the REAR o2 sensor, this is the one after the cat, it will give you a more accurate reading but will still be a little lean because it is AFTER the cat.

 

[DSMConvert]

you can run the a/f off the stock o2 sensor and it will work just fine, but as stated it will bounce around unless under full throttle, which is really the only time mixture matters....im hesitant to put an a/f after the cat, being as that over time the cat is destined to fail and hence give you false readings...well that is readings that will vary as the cat's inner combs start to get old and fail... we actually have a spare bung located at the base of the dp...it has a bolt on it on the passenger side, I would get a regular protege stock o2 sensor and use that for the af gauge...just my 2 cents...

 

[Notorious]

The only real use of the a/f on the stock sensor is too tell when the car goes into open loop operation. Thats at above 4000 rpm. It should stay constant rich.

 

[bruce95fmla]

that's because of the Garbage autometer gauges.

I would never put another autometer gauge in my car ...

 

[Ljspeed]

You get what you pay for. A 50 something dollar A/F gauge from Autometer is only gonna have readings past 4k like Notorious said. And yeah it may be useless if you live in a city with bad traffic and its not the most accurate. But if you want an AEM for example which is wideband or any other wideband A/F you will pay more than 150 dollars to get nice readings.

Same goes for my Autometer boost gauge, its a good gauge but a better one would be a GReddy. I wouldnt say all Autometer gauges are crap

 

[tracknfield423]

what are good gauges to get that are decently priced. i don't wanna be spending like $300 or so on 3 gauges when its just boost a/f and oil pressure

 

[Brian MP5T]

To answer the original question. It's normal and you will get used to it. Someone mentioned above but I will clarify a bit. A Fuel Injected car like the Protege uses a ECU, Mass Air Sensor, Injectors and O2 sensors to maintain ballance of the A/F ratio. Too much fuel, poor economy and performance. Too Little fuel, BOOM!

The Mass Air measures how much air is entering the engine and the ECU decides how much fuel to add with the injectors. Then the O2 Sensors tell the ECU how well the mixture was burnt and modifies the injector pulse. This happens constantly. The back and forth is the ECU Adding and Adding till it gets to the top of the parameter set by Mazda and then subtracting and subtracting until it's too low. Think of the A/F Guage like a thermometer that reads from 20.0 Deg to 20.1 Deg. It's a very narrow field of view and that's why it bounces so violently. As was stated... Lean should only happen when you let off the gas to slow down. No Fuel is required to stop as you know. Normally it stays Rich during load periods like over 120 Km/H. Hope it helped. Later...Brian

 

[Brian MP5T]

what are good gauges to get that are decently priced. i don't wanna be spending like $300 or so on 3 gauges when its just boost a/f and oil pressure

Unless you are planing to modify the boost pressure you don't need an A/F.

If you plan to Up-Boost, I would recomend keeping it at only +2 or 3 Psi unless you have a look at fuel delivery (Injector Size, Pump, Regulator) Later...Brian

 

[tracknfield423]

whats a good gauge to get tho that is decently priced and not too expensive. like i said before i don't want to spend like 300 bucks for 3 gauges and i have been told many times that autometer sucks

 

[Brian MP5T]

I have them and think that they are fine. Just because many people have them IMO does not mean that they are cheap or Ghetto. Their customer service department kicks ass and the products are inexpensive and work exactly as they should.

 

[tracknfield423]

so i'm fine with getting an autometer boost oil pressure and a/f gauge and i'll get good readings?

 

[Brian MP5T]

so i'm fine with getting an autometer boost oil pressure and a/f gauge and i'll get good readings?

They are still the most widely used company anywhere. Blitz, Apex-I etc make a really high quality product but do the same thing for more money. IMO

H8ters Dont bother. I'm not bitching about your opinion.

 

[acidbug]

i have a autometer a/f guage..works pretty good..i use it to tune my piggy back..

It works just as it supposed to!

It's just not as accurate as a wideband..if you ARE NOT plannin on boostin above 8-9psi..don't worry about a wideband!

Chas

 

[DSMConvert]

autometer gauges are fine! I ran a greddy and autometer boost gauge side by side and got the exact same readings all the way from 20psi of vacuum to 23lbs of boost...autometer is a widely trusted brand among domestic cars and is used on the IHRA circuit so I dont see where people get off calling them crap...I'd be more inclined to blame the installer than the gauge for inaccuracy...

 

[YellowMP5]

At idle and normal driving, it will bounce around from lean to rich. Under WOT it should go full scale rich. When it in gear and you have your foot off the gas pedal while going coasting, it will read full lean.

yeap, that's how mine is. all over the phreaking place. thanks redwagon02 (rick) for installing it for me.

 

[tracknfield423]

which autometer gauge do you guys suggest i get for my spicey orange msp. i have blue neons inside and my outside is obviously spicey orange with black cf hood and dgm grille. also the din pannel for my three gauges under the radio is going to be black cf.