A/F gauge owners...anyone getting usefull info?

[Cal Cruzer]

The A/F guages I have seen in the past on other cars have really been useless. The just bounce back and forth because they were hooked up to the stock 02 sensors which really don't give accurate enough readings. However, someone posted on a board that they thought the GT had wideband 02 sensors. If this is so, they would provide the right signal to produce good readings as this what most people had to add to get them to work right on Mustangs etc. Any feedback would be appreciated.

[dgc333]

I have continously owned at least one turbo mopar since 1985. All of the cars I added one of the LED A/F guages that bounce as you say. The real use of these is when you make modifications. The bouncing is caused by the closed loop feedback control of the engine management system. Whether you have a wide band or narrow band O2 sensor you will get this bouncing of the signal because the ECM is constantly changing the mixture.

At Wide Open Throttle (WOT) the engine mangement system goes into open loop operation and looks at parameters in a look up table and based on the values will set the duty cycle of the fuel injectors. When you start changing boost or modifing the exhaust/intake the ECM does not know this and you could get into a dangerous lean condition. It is under these conditions that the LED A/F guages give you and indication that you are running rich enough to prevent damage. With the 2.2 turbo mopar engines it is generally excepted that 9 of the ten LEDs lit is good under WOT.

[flashbk2]

Cal as dgc333 said the a/f is going to bounce ,even the instructions from autometer allude to this fact. What I'm using this for is when playing with my boost controller I want to see yellow on when boost is maxed and thoughtout it's range. If I see red then the boost needs to be lowered.

[Dalite]

The GT does have a wideband 02 sensor; 2 of them. However, they are biased with 2.5 volts, and can't be used with the A/F gauge that is looking for 0 to 1 volt..

If you are looking for a better sensor, try for one that has a heater, and outputs between .1 and 1.0 volts. The heater makes it more stable, where it reacts more with the O2 content, and less with heat fluctuations of the exhaust.

The GT has one in the exhaust maiifold, and one in the middle of the Cat. That way, it can tell both the A/F ratio and how effecient the Cat is performing.

Even with the heated sensor, you will see a lot of fluctuation in the gauges with a high count of LEDs or bar segments. The fewer segments, the less bounce. All you are really looking for is to stay out of the lean area...

[Cal Cruzer]

WEll, if the GT now has wideband 02's I remember seeing plans to build an A/F guage to give good readings. I will have to look them up. This is what people are using when they add a wideband to older cars to get useful info. I will post when I find it. thanks