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Discussion Starter #1
On a B13 ('92) if you unplug the O2 sensor while the motor is running... will that trip a check engine light or cause the car to change idle or any other effects??
 

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absolutely classic
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Modemagic said:
On a B13 ('92) if you unplug the O2 sensor while the motor is running... will that trip a check engine light or cause the car to change idle or any other effects??
Unplug it and see. The worst you would see is your car running rich. Like it hasn't warmed up yet. Just curious, but why do you need to know?
 

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Discussion Starter #3
Already tried the 'unplug and see' trick. I suspect my o2 sensor is trashed, but the ecu throws no codes, even if I unplug it. I think my car does run rich, I smell an abundance of fuel while it runs in the motor area. It never tripped the CE light, so I dunno if its supposed to and didn't, making me wonder if my ECU is jackked or what.
 

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TwiztidKidd
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I've never ever seen my B13 throwing any light ever, but I changed the original O2 sensor after 90k miles... A heated sensor will last you 100K miles max. Get the NGK sensor for 45 bucks... fuel economy has improved a lot ever since I got it. I dunno why the hotshot header gets a reading off of cylinder no.3 only (that's just not right) when the stock manifold is designed so the O2 sensor sends a feedback on all cylinders. Why is cylinder no.3 so special ?

 

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GA16DE
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Maybe it's the hottest or leanest?
In our beloved vw bugs n°4 was the hottest because it was offset from the cooling air flow...
 

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absolutely classic
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Modemagic said:
Already tried the 'unplug and see' trick. I suspect my o2 sensor is trashed, but the ecu throws no codes, even if I unplug it. I think my car does run rich, I smell an abundance of fuel while it runs in the motor area. It never tripped the CE light, so I dunno if its supposed to and didn't, making me wonder if my ECU is jackked or what.
O2 sensors don't seem to always trip CEL's. At least on my 96 they didn't and they were both shot. My gas milage went from 25 to 35 after I swapped some new ones in. Other than that, I didn't notice any change in the idle or anything. Maybe a little better throttle response too... I doubt there is a problem with your ECU.
 

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Beware of cheap sensors though. I read that Bosch were OE for these cars so I grabbed a 30 dollar once from Autozone and my car started stumbling in low RPM's. Gas mileage was still alright but it didn't run as well as it did with the old heat treated one that I suspected was shot. Since they do last so long and impact gas mileage so much it might be worth it to get an OEM part. Check www.courtesyparts.com or something.
 

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Vanilla Ice all the way baby!
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Modemagic said:
Already tried the 'unplug and see' trick. I suspect my o2 sensor is trashed, but the ecu throws no codes, even if I unplug it. I think my car does run rich, I smell an abundance of fuel while it runs in the motor area. It never tripped the CE light, so I dunno if its supposed to and didn't, making me wonder if my ECU is jackked or what.
O2 sensor failures do not set CEL's, why would it? it has no control over what the car does, the computer doesn't know its not working, it thinks the motor is messed up not the O2 sensor. when an O2 sensor fails the ecu read it as the engine is running lean, so it adds more fuel, over time this will change the fuel trim for the vehicle and eventually set a CEL for a lean engine, but the length of time needed to do that is not the same for all cars so i couldn't tell you

your ecu is fine, the only way to test an O2 sensor on an OBD1 car is with a digital multimeter and a t-pin, stick the t-pin into the signal wire of the O2 sensor (idk which one it is one your car, if its a 3 wire connector, slide the t-pin into the connector next to the wire, then attach the multimeter and with the car running check the voltage (set the meter to read DC voltage on a scale of 0-1v, if its working properly it should go below 200mV, and aboce 800mV

velardejose said:
Maybe it's the hottest or leanest?
In our beloved vw bugs n°4 was the hottest because it was offset from the cooling air flow...
the temperature if the cylinder has ablsoultly nothing to do with the reading, that just choose to put the sensor there, and there isn't a rich or lean cylinder, they all change from rich ot lean
 

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GA16DE
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I've seen a stock exhaust from a certain car (don't know make or model)
It had a single wire O2 sensor and has another single wire coming from what seems to be a thermometer (what other sensor could it be?)
If it's a thermometer, what kind of signal could I read with my dmm?
Thanks in advance
 

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Vanilla Ice all the way baby!
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velardejose said:
I've seen a stock exhaust from a certain car (don't know make or model)
It had a single wire O2 sensor and has another single wire coming from what seems to be a thermometer (what other sensor could it be?)
If it's a thermometer, what kind of signal could I read with my dmm?
Thanks in advance
in that case u need to find the power wire for the sensor, its a resistor type and the signal would come from the main power wire, becasue the sensor uses the threads to ground itself.
 

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GA16DE
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Sorry if I wasnt clear enough
The O2 sensor was there
The second sensor in the same exhaust manifold could be a exhaust temp sensor?
I was talking about reading this temp sensor variation alone, without ecu
 

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GA16DE
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A diesel... Only cars I've seen there were gasoline
Both were located just after primary tubes merge
I'll get a couple pics
 

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What is Seven Ten for?
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Twiz said:
Why is cylinder no.3 so special ?

maybe its just the easiest place they could put it?
I believe on my gen 4 header (b14) it is on #1.
 
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