AEM UEGO sensor testing??

[one_boosted_si]

I've got a UEGO WB on my civic that seems to be going out/ giving false readings.

 85-90% of the time the gauge reads full lean, no numerical display and - - -,  outputs a voltage of 4.xx volts to my Hondata EMS (normal lean voltage if memory serves correct from the manual) yet my car runs uber rich as per my blackened soot covered bumper and horrible gas mileage (180-200 miles out of 11 gallon tank with daily driving-not high load driving).

Is there any way of pin testing the sensor to check for function or is this a common problem after a while with these units? The unit has been installed on my car for approximately 1 year maybe.

Could this possibly be a concern with the gauge as sporadically it will go through it's opening phase and read in lambda when it's set for output for A/F ratio then actually switch to A/F ratio after a short drive? I doubled checked the back of the gauge and it was in position 1.

Any help would be greatly appreciated as I can't afford the gas or tune correctly with a gauge/sensor that doesn't work.

[tristanlee85]

It could be reading lean because you are running too rich. If you are dumping gas in there and raw gas is coming out the exhaust, all the sensor is going to read is the oxygen because there isn't an oxygen/gasoline mixture. Just oxygen and raw gas. Try leaning it out to see if it helps. As long as there is no load on the engine, the worst thing that will happen is the car stalls from being too lean.

[robssm]

Close..

There are 2 reasons to read lean and have gas chuggin out of the exhaust:

1) too rich - ie rich misfire.. You are wetting the plugs and its dousing your spark. You aren't lighting one or more cylinders, no burn = more unbonded o2 = lean.

2) misfire - bad sparkplug, bad coil, bad ignitor, bad wires, bad disty..  Once again, no burn = more unbonded 02 = lean!


When you have a combustion event, you combine nearly all free 02 with carbon, hence getting C02 ie nasty carbon emmisions that make everyone upset and makes dictators all around the world want to take all your money for carbon credits...

If you have no burn, the 02 goes into the intake, and goes right back out the exhaust.. High 02 reading is lean on the 02 sensor.

[HT]

heres a quick and easy test to see if your gauge/sensor are reading correcltly.

remember, the o2 sensor simply measures oxygen content in the surrounding air.

remove the o2 sensor
grab a rag, spray it with brake cleaner, denatured alcohol, acetone, gasoline,etc... pretty much anything that has fumes.
with the UEGO on and fully warmed up, put the sensor on the rag and cover it
with the sensor covered by the rag it will read full rich, pull it away and it will goto full lean (usually slowly)

[robssm]

OH, and I forgot the most nasty of them all:

Bad injector, bad injector driver, and/or bad injector connector... Hopefully its not any of these, and this can be a pricey issue to solve.. ie injector is not fully closing because you got some bad fuel or some other nastiness in the fuel lines.l..

[Adam R.]

what`s the O2 FB Coolant Min ? from Options - O2 sensor FB

[Mello]

HELP -> Context Sensitive Help ->
"Description:  O2 feedback will only operate when coolant temp is above this value."

[Adam R.]

thanks