How can I tell if my O2 sensor needs to be replaced? I don't believe I am getting the gas mileage that I should be (getting about 300-320 KM on a full tank). How much do these usually run from the dealer? This is for a 94 integra LS with about 170,000 KM. Most people I know are getting like 400+ on a full tank. TIA.

 

O2 sensors are like $50 US dollars I believe.

Have you done a tune up? Ignition, fuel filter, etc?

 

A new sensor from Honda here in Canada runs $226. Although some places carry an NTK (same brand as Honda) generic sensor (you have to transfer over the connector) for $60 or so.

To check the proper opperation you need a scope that can show the voltage output over time and count the cross-counts.

Although, at 170K km's, I would just replace it. On my own cars, I put a new one in with every timing belt.

 

Yes I have done a full tune-up except for a valve adjustment which I plan on getting done pretty soon. I hope that helps a little with the bad gas mileage.

 

take it out and use a multimeter to test it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by david90 &raquo;</TD></TR><TR><TD CLASS="quote">take it out and use a multimeter to test it</TD></TR></TABLE>

Can you or someone give some details on how to do this? My parents (auto) 98 LX is throwing a code 41 (o2 sensor) and we would like to make sure it's the o2 sensor that is bad before paying $60 for a new one. Thanks!!

Here's the problems:

1) Car shifts hard through gears. When shifted manually shifts normal.

2) Won't shift sometimes. Again under normal acceleration sometimes the RPM's will just keep rising and not shift say at 3k. They would let off the gas and wait for the RPM's to die down then accelerate again.

3) The gas gauge will sometime go to empty then back to half full

4) Car stalled and would not start again for several minutes.

 

do you have a CEL? if not, then I doubt it's the o2 sensor.

 

Code 41 is the heater built into the sensor. Check to make sure the wires are OK, check to make sure that it's circuit is getting 12v power when the car's running. If not, then you gotta check out wiring problems in the car.

Take a multi-meter & check the heater terminals on the sensor. Resistance should be 15 to 40 ohms. If the heater is fried it'll probably be an open circuit.

 

you won't be able to test it with a multimeter, they don't refresh fast enough. If you have a fluke meter with the bar graph, you can count the cycle rate, but it's still tricky. Check the heater terminals for the proper resistance. The problems you listed are NOT the result of a bad O2 sensor, though.