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I've had a rich condition for a while, and now that I've finally fixed my random stalling I've started to address it. I got my ZE installed a couple years back and for about half the time I've had it I've noticed carbon spots all over the bumper (white car, easy to see) So I got an autometer C2 air/fuel guage and installed it today. At idle, after it's warm and I've ran it hard for 15 minutes the guage sits with the last LED in the rich range lit up. Under very mild acceleration it stays entirely in the rich range, and cruising it bounces from the lean side of stoich to only one LED lit at the far end of rich.

So..... can anyone out there with a similar setup or otherwise comment on where their guage usually reads under these conditions? I'm sure it's spending too much time in the rich range, but I'm not really sure where the baseline should be.

In the directions for the gauge it says that it will bounce if mixture is right. It will always read rich when your foot is on the gas, and go lean when you let off. But at cruising speed it will bounce.
It being a low band A/F gauge, the accuracy is very low. But it will tell if lean or rich, To be safe if it idle just in the rich area you should be fine, just as long as if you floor it and it stays rich your fine.

Without a good catalytic converter you may get black on your bumper.

I say its the oxygen sensor(s)


Replace em..

narrow band is so innacurate but yah hes right you can know if its rich or lean.

Not accurate tho.

I would invest in a Wideband 02 and gauge. Don't try to tune your car on a narrowband 0xygen sensor.

the gauge you have is good if you wnat it to look cool (which it does i agree i have one mostly for that reason.lol) But they are not that acurate. if you o2's are poperating correctly it should bounce back and forth when at idle or when you foot is not on the gas. once you give it gas it should jump to lean for a second and then go to what your redaing is.If its showing you the last light in Rich then your running pig rich. also why your rear bumper is black.

I have a probinator ecu and my gauge goes to the last light in stoitch. i'm not ruch at all.

I guess I should change my sig, I am running a Probinator ecu chip now. I have a high flow cat that I really can't remember the make of. Thing is, when A-Spec put in my ZE and headers they negleted to re-install a cat. Which I found out a year later when I got my monza exhaust. The rich condition started before I even had a cat with this engine, but not right after the install.

I'll look into some wideband o2 sensors. Any recommendations? Would it make a difference if I replaced both with wideband? Neither one of my O2s are more than a couple years old.

unless your going with some type of management do not get widebands, its going to be a waist of money on your behalf. unless you just want to spend 300-500 for 2 widebands just for the hell of it.

Ouch, that's crazy. I don't need a super accurate reading that badly. I already know it's running rich, I just gotta figure out the cause now.

is it giving you a cel?, have u checked resistance on the coolant temp sensor?

and those gagues is what we called disco gauges, up and down, there not accurate at all, all they read iis the voltage from the 02 sensor. most cars with obd1 and obd2 will reach 0.7+ on the 02 sensor voltage after 3\4k+ rpm, thats why your gauge goes all the way up to rich.

you don't really need a waideband either. if you go tune the car ona dyno they usually ahve one you can use there.

The only CEL I have is for my FPR, I have an Aeromotive installed tho and it's working fine. My coolant temp sensor is about 1year old and checks out ok. I don't think there's sensor I haven't either checked or replaced in the past 2 years.

Have you checked your fuel injectors? They arent leaking into the cylinders are they? Might get them flow & pattern tested to make sure they are in spec. Just a thought

Tunes67

If you have a spare VAF lying around - try that - just one more thing to eliminate...

Hmm, something tells me that aftermarket FPR has to do with it, but i dont really have a lof exp with them, have u tried the factory one?

mine used to run rich but eversince i did the blaster/hei mod my motor runs stoich unless i really get on it, which i dunno it might have been an issue with the wires cause patdiesel and myself redid the wiring job when we did my hei/blaster

I doubt it's the AFPR, I've got a fuel pressure guage in the car and the pressure is bang on, jumps up real crisp on acceleration. Unlike the Cosmo one I had before it which couldn't maintain a solid pressure, and mysteriously stopped increasing psi on acceleration one day.

Mnemonic, how much of the wires did you redo?