My A/F gauge only works well when I'm at WOT (or close to it). When I'm at idle, or when I'm only giving it a little gas, the led's rapidly flash back and forth in between the first red light and the last amber light. Is this unusual, or does this gauge really suck that much. When at WOT the gauge works very well and in my opinion gives a fairly accurate reading. I got the gauge mainly for looks (as I know it's not very accurate), but the flashing back and forth is very annoying. BTW, in order to get a reading I tapped into the O2 sensor wire coming from the ECU. Anyone have any suggestions?

 

Try comparing the signal led's shown when you run another lead to the 02 sensor on the front bank wiring harness...then see if it is just off the ecu it looks funny...if you need to know what it looks like I can send you a pic...email me if necessary.

 

That is entirely normal for the autometer A/F. If you want one really accurate, you have to shell out $250 or so for the Greddy which comes with it's own O2 sensor, or even more for the Tomei unit, which also comes with it's own O2 sensor. You can get the greddy at www.gruppe-s.com not sure about the Tomei, both the greddy and tomei use a needle, not the LED's.

 

I'll probably just put up with it until I can afford to purchase an Autometer EGT gauge. I've heard it's not that hard to install and it will look better with the Voltmeter and Oil Pressure gauge that sit in the DIN panel. The A/F gauge looks a little out of place anyways. BTW, there's a pic of the DIN setup on my homepage.

 

This is 100% normal. I don't think it matters on what brand gauge you get, they will all do the same thing.

Don't worry. I had one too and thought that the jumping lights were annoying, but after a while, it was kinda cool.

 

The reason your leds flash back and forth at low throttle settings is because your ECU tries to maintain a stoichiometric A/F ratio based on what the oxygen sensors are telling it. The O2 sensors are a very nonlinear device that change from a high voltage at less than stoichiometric to a low voltage at more than stoich. (it may be the other way around). The A/F range at which this jump happens is very narrow. The ECU takes the signal and adjusts injector pulse width to either enrichen or lean out the mixture, causing the O2 sensor signal to jump to the other extreme. This happens many times a second, so the net effect is a stoich. A/F ratio on average. But the A/F gauge sees the O2 signal bouncing around and dutifully records it with the flashing leds.

At WOT, the ECU ignores the O2 signal and goes to a premapped, rich A/F ratio. The O2 sensor senses the steady fuel mixture and the A/F gauge displays the steady signal. Since the fuel map is based on a stock engine without mods, going to nitrous or boost may result in a less than rich mixture due to additional air, hence the need for a rising rate FPR or supplemental fuel nozzle to maintain a healthy A/F ratio.

 

[QUOTE]Originally posted by Stephen Max
Stephen Max is right. You're seeing the fluctuation of the closed-loop response of the control system.

 

Autometer A/F gauge = light show

It's actually almost embarrasing cuz I look like a ricer. The stupid thing just blasts back and forth the whole time. Regardless of why it does it, it still looks stupid and I'm actually thinking of trashing mine.

 

the flashin lights go with the music

 

I agree with James here. I bought the gauge mainly for looks, but it should still serve a function. Right now, it's just a light show......I might as well get a neon-lighted shift ****.

 

It does serve a function - at WOT when the engine is in open loop mode. It's only useful, though, if you're boosted or running nitrous. Most other mods don't have enough effect on A/F mix to cause the engine to run lean when in open loop mode.