I put in an air/fuel ratio gauge hooked up to the stock Fiero narrow band O2 sensor.

It's working fine, however, it tells me I'm rich. I didn't think I was. I have to go out in the morning and pull a couple of plugs to confirm the rich condition, however, is it possible the Glowshift is not accurate? I know it won't be as accurate as a wide band, but it should be generally accurate enough to determine richness. I think.

Anybody using Glowshift and does anybody know about the accuracy?

Thanks

Arn

I'm using glow shift for fuel pressure and boost... seems pretty accurate to me. Fuel pressure reads what it should and so does boost/vacuum.

Maybe its not the gauge, maybe its your O2 sensor reading incorrectly?

pretty sure you need wide band for accurate readings, its either on or its off with your set up

[This message has been edited by nosaint (edited 05-19-2010).]

I have a new o2 sensor on hand. Maybe I should try it.

Arn

I don't think your new O2 sensor will make any difference. As noted above, any time you are looking for an accurate reading, you need to be using a wide band O2 sensor. Most people I know have a separate O2 bung welded in to accommodate an extra O2 sensor.

While wideband is the only way to make accurate measurements of the A/F ratio, those bar graphs gauges that hook up to your existing O2 sensor do give you some idea of the fueling. If it reads way rich or way lean, the mixture probably is. That gauge that you have is basically a DC voltmeter that reads 0-1V. At cruise consitions the readings should fluctuate around the midpoint or slightly above. Upon acceleration or at WOT the bar should go into the rich zone. If it always reads very rich then the engine has a problem or the O2 sensor is bad.

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[This message has been edited by Dennis LaGrua (edited 05-19-2010).]

Well, I'll try the new o2 sensor and if it is the same result, it likely is rich. It is staying firmly in the rich area, except on decelleration, so it is definitely reading the gas influx to the engine, vs fuel starvation on decelleration.

I was looking for something in the "normal" area which is about a 60* sweep. I'll post what I find tomorrow.

Arn

If it's the kind of gauge that's made up of LEDs that illuminate sequentially, then I'd bet it's pretty accurate and reliable, regardless of the brand.

Grounding is critical with this kind of sensitive instrumentation. Don't ground the gauge to the nearest bare metal - any potential difference in the ground will influence the gauge's reading. Run a dedicated grounding wire from the gauge to the engine block.

On the OEM fuel injection system, in closed loop operation, the ECM will consistently enrich and enlean the mixture to stay around the stoichiometric point. The gauge will bounce between rich and lean in closed loop.

You have a carb. It's entirely possible that the AFR is almost always richer than stoichiometric - so don't expect it to bounce around like EFI.



The narrowband oxygen sensor is only really useful for telling you one of two possibilities:

1. Richer than stoichiometric
2. Leaner than stoichiometric

A "rich" reading on a narrowband sensor could mean either:

14 AFR which can be normal during cruising around

OR

10 AFR plug fouling rich

You don't really know... Take a look at the effect of temperature on the sensor output voltage...

Thanks PM. + for you.

I'm going to pull a couple of plugs after lunch and "read" them. If they look tan and clean, I'll try the new O2 sensor and I'll extend my ground. The ground wire goes to the shifter area in the console. It's easy to extend.

Arn