del91_305

I was curious on how one of these works. I am going to switch my TBI over to a carberated setup, and i was wondering if i do this if i would still be able to use a air/fuel gauge? I know you hook it up to the O2 sensor, but not sure on the rest.

Apeiron

Nothing to it, three wires on the gauge itself: power, ground and sensor. Two more for the backlight.

del91_305

But if you dont have a computer do you still have an O2 sensor?

ShiftyCapone

iTrader: (7)

No. Well you could have one but it wouldn't serve any function. By going to a non computer controlled set-up your car is no longer using any closed loop feed back. I would use a more accurate 02 then a single wire. They are horribly inaccurate and your gage is pretty much useless. I have been running the autometer AF gage for a few years now. Little did I know.

Shagwell

I run one. Nice to have, deffintely helps you tune a carb. I wouldn't use it to fine tune from, thats what spark plugs are for. helps you get close though, and helps you check part throttle and cruising situations. Mine's running a regular Bosch single wire O2. My plugs are tan colored, and when I mash the throttle, the guage will "fan" out across stoich. I like it...

later, justin...

Apeiron

"Fan out" across stoich?

ShiftyCapone

iTrader: (7)

I think is saying that his gage will have a few lights lit up right around the 14.7 (stoich) mark.

Apeiron

I wouldn't really want my car at stoich when I mash the gas.

del91_305

Now im confused, one of you say that it wont wok, but the other says it does work with a carb. Maybe if i switch to carb i have to keep my computer?

ShiftyCapone

iTrader: (7)

Single wire 02's are useless to determine actual AF ratios. A wide band 02 is the only thing out there that can. You can run an 02 without a computer if you have a carb. There are a few ways of doing it along with a few kits out there.

Apeiron

I don't know if I'd say they're entirely useless, just pretty inaccurate. A wideband is certainly much better.

SNET Telly

Get a wide band, make sure you look at how much the replacment sensor is when shopping around.

del91_305

Ok, i understand now, thanks alot

Dewey316

No, the issue has to do with how the computer uses the o2 values to modify the fueling. So instead of having an o2 value stay around .450v like you would on a carb, it will swing form say .200v to .800v and back to 200 then back to 800, etc.

tom3

Have an Edelbrock AF meter on my old Camaro. Seems to work pretty darn good. Really have the carb dialed in, but it's a lot of work to get it right. Big improvement in gas mileage and note some performance help too. Well worth the money in my opinion.

MurcoRS

My Auto Meter A/F gauge #3375 instructions call for a single-wire O2 sensor like a Bosch 12014. It specifically says it is not designed to operate with a wide-band sensor. You can use a heated one, though.
If you are converting from a TBI system to carb just leave the o2 sensor in and use it with the gauge only.

rgarcia63

O2 sensors are about emissions, and fuel economy not performance they're needed because catalytic converters work best when the mixture varies between lean and rich every few seconds.

A Wide-band 02 sensor would certainly help reduce the amount time it take to tune a carb although most gearheads I know say they can tune it faster by ear, my hearing is very bad.

That's why I like EFI, but unfortunely I'm required to pass emissions.

Apeiron

It's not so much a question of the mixture needing to change every few seconds, it's that narrowband sensors respond so slowly.

Twelvz

agreed with whats been said here. I wouldn't get one again. I'd take mine out if it wasn't such a pain...and I'm on boost. Innacurate and the further the sensor is away from the combustion chamber more innacurate it becomes.

Apeiron

Right, the response of a narrowband sensor changes greatly with temperature at the rich and lean ends.