HELP!!! my oxygen sensor is not working :(

[holdenrocks]

hello everyone,

My vr is run too rich and i could smell it out of the exhaust as found out on Gas Analyze.
the oxygen sensor is not working properly. as i was replace them about 1 month ago..

so i was check on the fuel trimming (see if anythings still work or not) and found oxygen sensor got no signal.

so i think oxygen sensor faulty or wiring broken somewhere or earth is not work properly..

so PLEASE HELP!!!!!!!

thanks

 

[Michelson4301]

no signal ? what was it reading on the scantool/multimeter/oscilloscope

 

[holdenrocks]

on scantool and oscillospe, and reading say zero.... and was check on the ecu to get signal but still no signal so what could i do ???

 

[holdenrocks]

anything about this as u know??? as i was look up on manual book and didn't find anythings about this

 

[Michelson4301]

check for continuity to earth/ground. sounds like the wire is shorted out. disconnect the oxygen sensor and also check to see if the "trace" voltage appears. ECU sends out around 451mv trace voltage to aid in sensor warm up.

 

[holdenrocks]

ok .. so do anyone have wiring diagram for this o2 sensor place ????????

 

[holdenrocks]

hey, got the signal due the bad earth/ground.... then check the waveform on oscillospe, there didnt tell me anythings because there run too rich as cant ready the voltage. i try to disconnect the air hose from brake booster .. didnt get big drop, just got little drop...

might need to check fuel injector if there have some leaks ???

cheers

 

[Michelson4301]

ok ? so you've got a signal at the PCM connector ? what about the earth reference wire ? another circuit to check is voltage drop between:- battery and engine, battery and vehicle body, engine and body. All should be checked with a reading in mV. The electrical system needs to be loaded to get a good idea of what is happening ie. fan speed 2, parkers on, ignition on-motor off, stereo on low. Checking fuel pressure and doing an injector leak down test is also good.

 

[holdenrocks]

yea, found the mV and its run too rich, say abt 700 to 850mV, i will go to get fuel injector leak test asap as if i can do. thanks for help .. cheers