narrow band autometer gauge

[one92rs]

i got an autometer narrowband air fuel gauge. it seems to jump aroun d more than i thought it would. the gauge is good. now for my question. could it jump around due to me having a heated 4 wire 02 sensor instead of a single wire 02 sensor. i know the signal is suppose to be the same. but!! would the newer 4 wire 02 sensor read faster than the older single wire 02 sensor causing the gauge to fluctuate so much.

[RobertISaar]

the reading will fluctuate a LOT in closed loop.

[EagleMark]

Yeah I think I've seen them with the LED lights? They work well on a narrow band O2 sensor by itself for like tuning a carb. But when hooked up to the NB on an EFI system you get to see the cross counts.

[one92rs]

so would it settle down with a regular one wire 02 sensor verse the 4 wire 02 sensor?

[EagleMark]

Not if it's still hooked up to the ECM in closed loop. In closed loop the ECM keeps cross counts going back and forth across stoich.

Unless there's another way to wire it?

[RobertISaar]

not that i'm saying it's a good idea, but a resistor/capacitor combo would essentially average out the signal and make the swingin much less noticable.

response time to new conditions would suffer though.

[lightning-jr]

Your gauge needs it's own sensor mounted in the exhaust, then all will be happy.

[Six_Shooter]

Your gauge needs it's own sensor mounted in the exhaust, then all will be happy.

No it doesn't.

The jumping from rich to lean in closed loop, while cruising or at idle is perfectly normal.

[EagleMark]

Right but for the gauge to work properly and not jump would need it's own NB O2 sensor is what he's saying...

[Six_Shooter]

Right but for the gauge to work properly and not jump would need it's own NB O2 sensor is what he's saying...

Still not the case.

It will still bounce from rich to lean, even with it's own sensor.

Besides it's a lot of work for a NB gauge, to add another sensor for something that really equates to not much more than some dancing lights.

[PJG1173]

for that much effort I'd put a WBo2 in and get some useful info from it.

[EagleMark]

Still not the case.

It will still bounce from rich to lean, even with it's own sensor.

Besides it's a lot of work for a NB gauge, to add another sensor for something that really equates to not much more than some dancing lights. Years ago I rigged up a 7747 with power, ALDL and O2 for the 1 volt and did get a steady reading, more of an experimant to me and forget all the changes needed but did work, it was just a jury rig situation to help a guy tune his carb. But your right even with another sensor the ECM will still throw cross counts, now if you add another sensor and can get clean 1.0 volt it does work. Why bother? I don't know...


for that much effort I'd put a WBo2 in and get some useful info from it.Yup!

So you got the gauge, was there any info on how to get a NB O2 sensor powered for gauge without ECM? Depending on ECM I have seen some stop cross counts in certain situations. Like my LT1 in WOT I get steady o2 readings from each side. No cross counts...

[RobertISaar]

Mark, carb or computer controlled carb?

one should cause swinging, the other shouldn't. well, not much anyways, compared to a CCC/TBI/MPFI.

at WOT, you shouldn't be getting cross counts... if you are, that means you're switching from lean to rich over the stoich point.

[PJG1173]

So you got the gauge, was there any info on how to get a NB O2 sensor powered for gauge without ECM? Depending on ECM I have seen some stop cross counts in certain situations. Like my LT1 in WOT I get steady o2 readings from each side. No cross counts...

shouldn't need power to the O2 unless its to power a heating element. the o2 will generate its own electricity to create the signal voltage.

[EagleMark]

It was a 1227747 I used the O2 sensor wire for, hooked up to power, ALDL for data and I forget what changes I had done to chip... I thought the ECM supplied a 1 volt to O2 on that? It's here in a box somewhere, worked then help him get right jets in his carb car with no CCC ECM. Like I said it was more an experimant for me and worked well for him, probably a simpler method but that's all I knew how to throw together.

So with a seperate O2 sensor to gauge it'll work?

When I finish this harness on my test bench and get it running I'll have to check now just for curiosity...

[Six_Shooter]

Years ago I rigged up a 7747 with power, ALDL and O2 for the 1 volt and did get a steady reading, more of an experimant to me and forget all the changes needed but did work, it was just a jury rig situation to help a guy tune his carb. But your right even with another sensor the ECM will still throw cross counts, now if you add another sensor and can get clean 1.0 volt it does work. Why bother? I don't know...

See the enlarged and bolded text for your reason why it didn't swing. ;)


So you got the gauge, was there any info on how to get a NB O2 sensor powered for gauge without ECM? Depending on ECM I have seen some stop cross counts in certain situations. Like my LT1 in WOT I get steady o2 readings from each side. No cross counts...

The O2 does not require power to work, unless there is a heater element. The O2 sensor creates it's own signal voltage. To use a NB gauge, all you would have to do is connect the gauge as normal, and connect the signal wire directly to the O2, no extra circuits needed.

[one92rs]

i have a 4wire 02 sensor. i guess you could call it that. the 2 grounds are hooked together. 1 power and 1 signal. was just wondering if it was because it was a newer 02 sensor that i was getting the movement or if it is just going to do that. when i floor it it goes to the second bar on the rich side. so what yall are saying is i am doing ok.

[lightning-jr]

Yes as long as the computer does cross-counts the gauge will fluxuate, sorry my previous answer was misleading. Isolating the gauge's sender will just slow it some.

You could try cutting proportional gains some, (to slow or narrow the swing), that's what drives the crosscounts.

Some guys narrow the o2 volt window.

[dyeager535]

I think the others were dead on saying that it's near pointless to run a narrowband O2 gauge.

Just my .02, but the only things a narrowband is good for (outside of it's intended OEM purpose) that might be useful on a gauge, is to ensure that you aren't going lean at WOT, and to ensure that your O2 sensor is swinging back and forth over stoich as it should be. If you are closed loop and it's not swinging under cruise conditions for instance, obviously something is wrong, but even then it's not necessarily showing a problem with the O2 sensor.

The "accuracy window" if you will, of a narrowband O2 sensor is so small that outside of over or under 14.7:1, the "voltage away from 14.7:1" is near meaningless.

However, if you stomp on the gas, and the gauge shows lean, you have a problem, so for crude WOT tuning (which is what I have to do, with no WBO2 myself) it could be useful for that. If you are datalogging for tuning though, having an O2 gauge is pointless, because you can see what the O2 is doing without having to physically watch a gauge.