i've been trying to get my air/fuel gauge to work even though i hear it is useless and just a light show (i bought it and installed it before i found this out).
anyways... my question is regarding the o2 sensor. when i took a volt meter and read the voltage on the o2 sensor signal wire (at idle) it reads a steady 0.3v.
the voltage is suppose to move up and down between 0.3v and 0.7v roughly at idle right? if so, does this mean my o2 sensor is bad since it stays at 0.3v.
and if i need a new o2 sensor, anybody know what o2 sensor i can use for a s13 red top?
also when i start the car with th o2 sensor connected or disconnected, the car idles the same and the voltage on the signal wire reads the same 0.3v.
do i need a new 02 sensor?
Actually your car doesn't run fine, if there was no O2 sensor input the ECU just either uses a pre determinded fuel map or just guesses. Usually they just uses a predetermined map and run the car rich to prevent knock/detonation etc.
Car will probably idle okbut have sluggish and crappy performance.
Car will probably idle okbut have sluggish and crappy performance.
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HYBRIDxS13
- Posts: 23
- Joined: Wed Nov 12, 2003 3:12 pm
i actually read other posts about other people not getting their air/fuel ratio gauges to work properly...
i decided to test the 3 wires from the o2 sensor plug. Again the signal wire reads and stays at 0.3v, the ground wire reads 0.0v (which it should be right?), but the strange thing is the power wire reads 0.0v as well...
shouldn't the o2 sensor power wire read 12v???
where is this power wire suppose to get the 12v source from? i read something about it leading to a brown plug by the battery location... is this right?
can someone please explain further or suggest any other fixes...
i decided to test the 3 wires from the o2 sensor plug. Again the signal wire reads and stays at 0.3v, the ground wire reads 0.0v (which it should be right?), but the strange thing is the power wire reads 0.0v as well...
shouldn't the o2 sensor power wire read 12v???
where is this power wire suppose to get the 12v source from? i read something about it leading to a brown plug by the battery location... is this right?
can someone please explain further or suggest any other fixes...
how about some car specifics?? year? engine? I assume its a 240 since you posted here.
the .3v you see is actually probably coming from the ecm.the 3 wire o2s are heated o2's the power wire is usually supplied voltage from a fuse. are you checking for the voltage with the connector disconnected? thing about o2's is they need to be tested hot or the signal will not be very active and its best tested at 2000 rpms. A volt meter is really not a very accurate wy to monitier the signal wire of an o2 since the meter usually doesnt have a high enough sample rate to catch each high and low sweep of the sensor. A dso is your best bet. hell even your gauge is a better way of monitering it then most meters.
the .3v you see is actually probably coming from the ecm.the 3 wire o2s are heated o2's the power wire is usually supplied voltage from a fuse. are you checking for the voltage with the connector disconnected? thing about o2's is they need to be tested hot or the signal will not be very active and its best tested at 2000 rpms. A volt meter is really not a very accurate wy to monitier the signal wire of an o2 since the meter usually doesnt have a high enough sample rate to catch each high and low sweep of the sensor. A dso is your best bet. hell even your gauge is a better way of monitering it then most meters.
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HYBRIDxS13
- Posts: 23
- Joined: Wed Nov 12, 2003 3:12 pm
i have a 89 240sx with a s13 red top sr20det... and i tested the o2 sensor power wire while it was plugged into the o2 sensor and with the car on (idled for awhile to give it time to warm up).
the o2 sensor is plugged in but i dunno where the wires go from there. i take it the signal wire goes to the ecu and the black wire is grounded somehwere... but where does that power wire end up???
the o2 sensor is plugged in but i dunno where the wires go from there. i take it the signal wire goes to the ecu and the black wire is grounded somehwere... but where does that power wire end up???