Help me test 02's.. how..

[Gerald]

Help me test 02\'s.. how..

Is there another way to test o2 sensors other than resistance? I've got an 02 sensor (upstream) and a voltage/ohm/ meter in my hand now.. The resistance tested at 5.8 ohms. what about the voltage? I've got a stumble (intermitent and sometimes worse than other times) and threw a code yesterday and it said bank 1 lean condition. PUlled the plugs from bank1 and they are carboned up only after 20 miles on the while bank2 is perfectly clean. .... New plugs, new wires too...
I've got simms for my rear 02's, so I assume all is ok with them....

Gerald

 

[Mike Brunton]

Re: Help me test 02\'s.. how..

Gerald,

The 02 sensor should read from 0-1 volt (that is it's range). It generally should fluctuate between 0.175 volts and 0.8 volts. It should do this quicker than you would see it on a digital voltmeter though (although you could see it on an analog I'd guess).

A way to test is to warm the car up, and check the voltage from the 02. It should fluctuate above and below about 0.5 volts.. down to .1 volt and up to .7 or so. If it stays high or low, and does not fluctuate then it is probably bad. You can do further testing (like putting propane in to see if it richens up, or make a vacuum leak to see if it leans out), but I would say if the sensor is not fluctuating up and down on the meter, chances are it's not working right.

A good thing to try would be to test both 02 sensors (left and right bank). If the bank 1 sensor doesn't "act" the same way the bank 2 one does, chances are it's *****'ed.

Hope it helps bud!

 

[Ulysses]

Re: Help me test 02\'s.. how..

Sounds lke the O2 sensor is working fine to me. I'ld say 90% of the time an O2 sensor is bad, the OBDII computer catches it and reports it as such.

The catch here is that you have sims for the rear O2 monitors. They usually help in monitoring and diagnostics of the efficiency and health of the cats and upstream O2 sensors. Some manufacturers, I think Dodge included, actually program the PCM to flip over to the rear O2 monitors in case of a upstream O2 failure to help regulate the A/F.

As far as I am aware, there is no easy way to diagnose a bad O2 sensor short of hooking it up to a oscilloscope and watching the pulses while it's in a known good system. The PCM is usually the diagnostic tool.

I'ld start looking for vacuum leaks, bad injector connectors, dirty injectors.

 

[Ulysses]

Re: Help me test 02\'s.. how..

One thing you could try is to switch the right and left O2's and clear the code. If the same code comes up, you've got a real problem. If the code switches to the other side, then the O2 is bad.

 

[Gerald]

Re: Help me test 02\'s.. how..

Thanx for the help.. I found a spare 02. how do I tell if it's a front or rear?

 

[Ulysses]

Re: Help me test 02\'s.. how..

The rears are two wire shielded, the fronts are heated and should have more than two wires.