I have a full rb exhaust setup and I have a cone air filter. anyways, I have a autometer a/f gauge, anyways at idle I noticed, that my gauge shows nothing at all. But if I get out of my car and walk around to the back of it, my exhaust smells rich. Anyways when I step on my gas, the a/f gauge lights up and starts working. shouldn't it be reading stoich or a little bit lean if im idling? if not what other problems do I have

 

hopefully my mods will post this time

 

actually it will probably read rich @ idle. Rx-7's inject air into the exhaust manifold at idle for emissions reasons. This throws the o2 sensor off and so its not used @ idle.

 

First off, lemme just say that the only time you could attempt to believe that hunk of crap gauge is at WOT.
But even then, its a piece of crap and you shouldnt trust it.


That being said, most A/F gauges will dither ( just go back and forth between rich/lean ) at anytime except WOT.
Also, is then when you first start your car? Or is it all the time? Your A/F gauge wont show a very good reading if your O2 sensor is cold.

 

There is nothing wrong with the Auto Meter AF gauge. I know several people who use it, including national-level RX-7 racecar drivers.

The ECU, not the gauge, "dithers" through the narrow-band O2 sensor crossing voltage. Yes, an unheated 2-wire O2 sensor will not read correctly when cold. See the gauge directions here:
http://www.autometer.com/hp/instruct...tions/837j.pdf

 

IeatV8s
On a car that still has a working ACV and air pump, what NONAMEO said applies. Due to the airpump injecting into the exaust ports at idle, you'll see a very low reading. But if you'll go to your Blue solenoid, which is the Relief SOlenoid, and pull the plug, most all the airpump air will go overboard. Then you'll see a high 02 reading on your gauge.

At least that's the way it is with my two N/T and one TurboII. Three out of three is a pretty good indication.

If you have removed your acv and airpump......I have no explanation for you.

 

Actually, that's when it's at its least accurate. The only time you can trust any A/F gauge reading off the stock O2 sensor is when the mixture is in very narrow range around stoichiometric. You're mistakenly blaming the gauge, when in fact you should be blaming the sensor. Actually you should be blaming whoever thought of using the O2 sensor for something it was never designed for.

 

http://www.techedge.com.au/vehicle/wbo2/default.htm

 

Its not like Im saying AutoMeter is crap. Im just saying that gauge is crap. Blame it on the sensor, blame it on the gauge, I dont care. In the end, the statement is the same ( Unless you just HAVE to get that technical over it ).

Point is, dont get one unless youre just looking for a pretty light show. If youre seriously concerned about monitoring your A/F, get a wideband system.
Otherwise, just tune it on a dyno with a wideband and leave it be. Thats what Im doing.

 

Like I said, if you want to get technical, go for it. The gauge still dithers and thats that. The lights go back and forth. Im not saying what causes it, just that it happens.

 

well I still do have the air pump and acv hooked up. and yes the gauge readings are different when the car is cold compared to when it is warm, but that's just common sense. I 'm talking about while the car is warm and idling it reads this, and I also notice while I'm driving the car, if I let off the gas but have not pushed the clutch in, it will go past lean and not show anything,then when i get back on it, it starts reading again. I just want to make sure I'm not running my car lean that's all.

 

It going off tha gauge lean when you let off the gas is normal. Dont worry about it.

 

That's because it's supposed to! When you're cruising the ECU goes into closed-loop and monitors A/F ratios with the O2 sensor and tries to keep them at stoichiometric. If it's too rich it'll reduce the injector pulsewidth; it's it's too lean it'll increase it. It does this many times per second, so you see that on the gauge as the LED's rapidly flickering back and forth around the middle (stoichiometric) point. This is how the ECU minimises fuel consumption at light load. If you ran the car at a constant light load on a dyno with a wide-band you'd see exactly the same behavoir.
When you accelerate the ECU goes into open-loop, ignores the O2 sensor, and reads it's internal fuel maps.
One of the uses of an A/F gauge is monitoring if and when the ECU goes into closed-loop. If it doesn't you know you have a problem somewhere. This sort of thing is what these gauges are most useful for. If you get used to what the gauge does, you can spot problems that cause it to behave differently. They cannot be used for safe tuning, but that doesn't nake them useless.
BTW, you may call it "getting technical", but to me it's just understanding how my car works.

 

If you bothered to read, I never said it wasnt supposed to...

I dont know why you guys are picking on me. I was just explaining to the guy what the A/F gauge will do and that its normal for it to do that.

 

Why is everyone so damn sensitive at the moment?

Nobody's picking on you. I'm just trying to share to some knowledge so others can understand a little better how these things work. And you did call them a piece of crap, which is incorrect. Sorry I bothered...

 

No, but you implied it. The implication may not have been intentional, but it did need to be corrected IMO. It is difficult to explain technical topics in these forums with just a few sentences, but we all make our best attempt. There is no reason to get upset if somebody corrects, clarifies, challenges, or debates your remarks. It happens to me all the time. I was even wrong one time if you can believe it.

 

I dont know about you...but reading this, "That being said, most A/F gauges will dither ( just go back and forth between rich/lean ) at anytime except WOT. ", would make me think that theyre supposed to do it...
I really dont know how you all think I "implied" it in any way...but whatever.


And Im not mad at anybody. Youd know it if I was

 

I dont think Im being "so damn sesnistive"...

They way you replied made me think that you thought I was saying they werent supposed to dither...But thats not what I said.


And any narrowband A/F gauge ( not just Autometer ) is crap. All their good for is a pretty light show.






EDIT- Actually, let me clarify that just for you. The gauge itself may not be crap. It reads, and displays the signal very well.
The sensor however is crap.
Is that better?

 

If youre really that desperate to know your A/F using a narrowband sensor, just get a used voltmeter for cheap and hook it up.

 

If you understand what you're actually watching, that pretty light show can be quite informative. It's just that most people only install it to read WOT mixtures, which it can't do. Actually, the sensor is very good at doing exactly what it was designed and installed to do. We are the ones who're using it for something it was never intended to be used for.
Jusy clarifying that.