Help with OBD II stuff - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Jessi · 10-01-2005, 10:34 PM

Ok, I need a little help because I'm clueless.

Should I have an O2 sensor in the exhaust manifold and one after the cat?

I have a feeling I'm missing an O2 sensor.. the car is running rich and I'm failing emissions. I'm not saying that it's the only problem. But, one of the codes it's throwing out is a rear O2 sensor. I had a mechanic look at my car today and he said it looked like an O2 was missing.

If I do have one missing, Midas is going to hear an earful from me.

***S14DB*** · 10-01-2005, 11:29 PM

You should have one in the mani and one under your ass.

ALTRNTV · 10-01-2005, 11:35 PM

Yes. There's one on the manifold and one right under your ass. Damn OBDII. The one under your ass will cost you.

projectRDM · 10-02-2005, 05:07 AM

The rear O2 is only used for diagnositcs, so even though it's missing that's not the cause of your car running rich.

Jessi · 10-02-2005, 10:57 AM

Thanks so much guys! I'm not paying for the one under the ass.

Midas' dumbass will be paying for it since they didn't put one back in after doing my exhaust.

R240NA, if there is one missing though, won't it cause like the pressure/air or something like that to leak out of an area it's not suppose to? I'm also getting the evap canister and vent control codes too. We're assuming with an O2 missing, it could be throwing both those codes as well. The mechanic said that the car shouldn't be throwing both those codes at once.

I am just so confused.. because I don't know what to do. I'm not good at explaining these kinds of things.

***S14DB*** · 10-02-2005, 04:19 PM

I've only replaced the front one and run fine. But, every once and a while I'll throw the rear code and the ecu will start dumping fuel. It doesn't do anything but can still freak out the ECU if not there.

Jessi · 10-02-2005, 04:21 PM

Yeah, I have the following codes right now, and I'm assuming the O2 sensor is causing them.

1. Speedometer Head (not emissions related and nothing is wrong with it, but the check engine light never goes off, so we're assuming that's why this code is there)
2. Rear O2 sensor (not even on the car)
3. Evap canister
4. Vent control valve

***S14DB*** · 10-02-2005, 04:31 PM

1. IIRC is the VSS. I would have to check the big black book at home.
2. Is the 02
3&4. Is that shit in your rear pass. fender behind the wheel. Been hit in that quarter? rip that shit out?

Jessi · 10-02-2005, 04:33 PM

I've never been hit on the passenger quarter panel. Just the drivers side.. twice!! This is all such a freaking headache. Give me your car. Haha.

projectRDM · 10-02-2005, 05:31 PM

Quote:

Originally Posted by Jessi

R240NA, if there is one missing though, won't it cause like the pressure/air or something like that to leak out of an area it's not suppose to? I'm also getting the evap canister and vent control codes too. We're assuming with an O2 missing, it could be throwing both those codes as well. The mechanic said that the car shouldn't be throwing both those codes at once.

I am just so confused.. because I don't know what to do. I'm not good at explaining these kinds of things.

You'll have an exhaust leak, but I'm pretty sure you'd hear it. More likely it's just unplugged, either way it's not affecting anything else because you've already expelled what you need through the converter. You could cut the exhaust off right where it the sensor resides and the only downside would be volume.
The other two are likely caused by something else, I've seen cars with both of those codes and there wasn't any reasoning other than bad gas, age, wear, etc.

Jessi · 10-02-2005, 10:52 PM

Yeah, but my exhaust was custom made. And they didn't make an O2 sensor bung. I just now found this out yesterday when I took it to a real mechanic who actually took the time to look at the car.

10-01-2005, 10:34 PM	#1
Jessi Leaky Injector Join Date: Nov 2003 Location: Arizona Age: 41 Posts: 124 Trader Rating: (0) Feedback Score: 0 reviews	Help with OBD II stuff Ok, I need a little help because I'm clueless. Should I have an O2 sensor in the exhaust manifold and one after the cat? I have a feeling I'm missing an O2 sensor.. the car is running rich and I'm failing emissions. I'm not saying that it's the only problem. But, one of the codes it's throwing out is a rear O2 sensor. I had a mechanic look at my car today and he said it looked like an O2 was missing. If I do have one missing, Midas is going to hear an earful from me. __________________ Sweet! That is tricked out my friend. Turbo!

10-01-2005, 11:29 PM	#2
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	You should have one in the mani and one under your ass. __________________ Comments should be taken as Opinions not as Statements of Fact

10-02-2005, 05:07 AM	#4
projectRDM Post Whore! Join Date: Dec 2002 Location: Atlanta Age: 51 Posts: 13,812 Trader Rating: (12) Feedback Score: 12 reviews	The rear O2 is only used for diagnositcs, so even though it's missing that's not the cause of your car running rich. __________________ FORMERLY R240NA Learn what's really going on and protect your assets now before they're gone forever: www.paypalsucks.com

10-02-2005, 10:57 AM	#5
Jessi Leaky Injector Join Date: Nov 2003 Location: Arizona Age: 41 Posts: 124 Trader Rating: (0) Feedback Score: 0 reviews	Thanks so much guys! I'm not paying for the one under the ass. Midas' dumbass will be paying for it since they didn't put one back in after doing my exhaust. R240NA, if there is one missing though, won't it cause like the pressure/air or something like that to leak out of an area it's not suppose to? I'm also getting the evap canister and vent control codes too. We're assuming with an O2 missing, it could be throwing both those codes as well. The mechanic said that the car shouldn't be throwing both those codes at once. I am just so confused.. because I don't know what to do. I'm not good at explaining these kinds of things. __________________ Sweet! That is tricked out my friend. Turbo!

10-02-2005, 04:19 PM	#6
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	I've only replaced the front one and run fine. But, every once and a while I'll throw the rear code and the ecu will start dumping fuel. It doesn't do anything but can still freak out the ECU if not there. __________________ Comments should be taken as Opinions not as Statements of Fact

10-01-2005, 11:35 PM	#3
ALTRNTV Post Whore! Join Date: Mar 2003 Location: Western Conference Posts: 9,429 Trader Rating: (0) Feedback Score: 0 reviews	Yes. There's one on the manifold and one right under your ass. Damn OBDII. The one under your ass will cost you.

10-02-2005, 04:21 PM	#7
Jessi Leaky Injector Join Date: Nov 2003 Location: Arizona Age: 41 Posts: 124 Trader Rating: (0) Feedback Score: 0 reviews	Yeah, I have the following codes right now, and I'm assuming the O2 sensor is causing them. 1. Speedometer Head (not emissions related and nothing is wrong with it, but the check engine light never goes off, so we're assuming that's why this code is there) 2. Rear O2 sensor (not even on the car) 3. Evap canister 4. Vent control valve __________________ Sweet! That is tricked out my friend. Turbo!

10-02-2005, 04:31 PM	#8
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	1. IIRC is the VSS. I would have to check the big black book at home. 2. Is the 02 3&4. Is that shit in your rear pass. fender behind the wheel. Been hit in that quarter? rip that shit out? __________________ Comments should be taken as Opinions not as Statements of Fact

10-02-2005, 04:33 PM	#9
Jessi Leaky Injector Join Date: Nov 2003 Location: Arizona Age: 41 Posts: 124 Trader Rating: (0) Feedback Score: 0 reviews	I've never been hit on the passenger quarter panel. Just the drivers side.. twice!! This is all such a freaking headache. Give me your car. Haha. __________________ Sweet! That is tricked out my friend. Turbo!

10-02-2005, 10:52 PM	#11
Jessi Leaky Injector Join Date: Nov 2003 Location: Arizona Age: 41 Posts: 124 Trader Rating: (0) Feedback Score: 0 reviews	Yeah, but my exhaust was custom made. And they didn't make an O2 sensor bung. I just now found this out yesterday when I took it to a real mechanic who actually took the time to look at the car. __________________ Sweet! That is tricked out my friend. Turbo!