autometer a/f gauge question

[goldenchild]

I just install a autometer a/f gauge and I only get a reading when the gauge is directly hooked up to the o2 sensor and the ecu o2 wire is not used, I tried the gauge with the ecu o2 line and I get a reading that says extremely lean and doesnt move to stoich or rich when i get on the gas, sometimes theirs no lights at all: lean, stoich, rich (1990 240sx ka24e). To my understanding all u had to do was connect the purple signal wire to the ecu o2 wire coming from the o2 sensor

[solaris22]

you've got pretty lights just in time for christmas

[goldenchild]

seriously, i dont need any jokes

[IvoryJ30t]

well, if were gonna get all flustered about our near-useless blinking lights not working, then go run off and make sure you ground the meter to the same ground as the ecu. a narrow band O2 sensor has a range of one volt. any difference in potential between the meter and the ecu will cause an inaccurate reading.

[goldenchild]

would different grounds cause the gauge lights not to come on

[IvoryJ30t]

seeing as how your trying to monitor a single volt [.01-1.00 vdc] you want the gauge to have the same ground as the ecu. any difference in the electrical potential of the ecu's power-ground and the gauge's power-ground, will give you a bad reading or no reading at all.

oh, and the gauge is useless for anything other than entertainment. only during cruise/idle will the meter bounce around. during acceleration the meter will be pegged full rich.

[goldenchild]

Since the gauge is usless , whats the best piece of equipment to monitor the a/f ratio, or is it even worth it

[IvoryJ30t]

its nice too look at, but its not a tuning aid.

if your tuning, you need a wideband O2 sensor setup and an EGT gauge.

[IvoryJ30t]

egt isnt needed, but its a good thing to have.

[goldenchild]

thanks for the info

[IvoryJ30t]

if you dont want to spring the 3-500 for the wideband, take the car to a dyno. they usually have the equipment, and tune it on the dyno.

[S13240]

EGT isn't needed, but it's similar to an a/f ratio gauge. Just tells your when your engine is running lean or rich by temperature instead of voltage/leds.

[solaris22]

if you want a a/f gauge I'd suggest an analog, they're actually very helpful. I wouldn't suggest getting a wideband unless you plan on tuning your car yourself (PowerFC, haltech, Tec3 ect..)