Chris Gregg

iTrader: (59)

I've been feeling a slight power loss for some time now but blew it off as paranoia. While installing my custom CAI a few weeks ago, I noticed something I could never see before. Below the Battery bracket plate there is a vacuum reservoir with three holes comming out the top and one on the bottom. One of the hoses had broken off that appeared to feed into around the intake. I assume this has something to do with vacuum advance or idle control, something! A sticker on the canister said " IGN VC." I got another canister (for free) from my local "junk dealer" and put it on, there was a significant difference in power and response. This is even after plugging up the loose hose and the input point for the hose on the canister. This is worth checking out, any vacuum leak can cause performance problems and something so simple just to check, it's worth everyone's time to do so!

Guest

I had similar problems with power loss after the engine was warm. The car would stall or stutter from a stop. Under full throttle it felt bogged down. Like you I originally wrote it off as being my imagination but it progressively got worse.

I was told it might be my plugs, fuel filter, or catalytic converter, O2 sensor, or air mass sensor. I replaced them all except for O2 sensor and air mass sensor but still had power loss after the engine was warm. I finally replaced the O2 sensor. Big difference, feels like a new car plenty of power...always.

The problem was when the car was cold it was running in "open-loop" mode where the computer estimated the proper air/fuel mixtures without input from ther O2 sensor. After the engine (& O2 sensor) warm up the on-board computer relies on the O2 sensor for input in determining the air/fuel mixtures. Bad O2 sensor = poor performance.

You can check the O2 sensor by stripping back some of the wire insulation and connecting a multimeter. If you don't get voltage transitions while reving the engine then thats a good indication the your O2 sensor may be bad. I believe the typical voltage output from the sensors is ~1 volt.

My car has a hose under the air mass sensor with a curved/looped end (don't know if its the same one you are referring to). I was told that it was a vent for the transmission not a vacuum line. You may want to have a transmission shop verify whether yours is a transmission vent.

Hope this helps...good luck.

Jon Little

I was wondering where to get a new O2 sensor and when I put a CAI or a pop charger on the sensor is connected right? Is there a diagram or directions for this replacement?

Matt93SE

iTrader: (44)

The O2 sensor is attached to your exhaust, just in front of the catalytic convertor. looks kinda like a spark plug.

the Bosch (OEM maker for nissan) replacement # is 13387. Check on carparts.com's website for a price.. last time I looked they were just under $100.
I bought the same one from a local parts store today for $126 after tax..

if you go through carparts.com, you can get a 33% off coupon, so you'll end up paying about 1/2 of what I did for it.

Chris Gregg

iTrader: (59)

Thanks, but this was more of an answere than a question. I was just mentioning something that I'm sure most of us don't think about, the vacuum lines. I've also got a fuel pressure riser that automatically adjusts pressure due to vacuum, so loosing vacuum is something I can't afford to let happen. I was simply stating that I had found a busted line (which has vacuum) which ran to a tank (charcoal canister) that is mounted under the battery. Upon fixing the tube by replacing the broken canister, the car had better response and power. Having cars that are around 10 years old and an item that is out of site for inspection, I thought it necessary to mention it for those who, like me, had felt a small loss of power and thought nothing of it.

SeaMAX

iTrader: (2)

My car has 168K on it and I don't think when I bought it the previous owner has changed it. What are the symptoms of a bad O2 sensor besides lost in power.

NYC GS4

iTrader: (2)

Acostar

Now I did every single thing possible except for 02 sensor and am still unhappy with the car's acceleratyin most times. I recently unplugged it for a few days and the car felt the same with or without it. The only thing stopping me from paying $115 for the new one is that from what I understand it just smooth's out your idle( Basically only noticeable if you have a gun to measure idle speed) and maybe some slight hint of better throttle response. I've never seen anyone mention results like you have, and also my MPG doesnt really blow. Try to give me more details if you can, thanks.

Nismo87SE

Get a haynes or FSM and follow the procedure on testing the o2 sensor. It could save you from wasting $115 on an o2 sensor when you can get a RSB or axxis MM pads.

trbo

im taking the max for emissions, the last time it failed, due to bad o2 sensor. since then, two years ago, its been changed another time, about a year ago. Now im getting the same symptoms as b4, when abusing the car a bit, shifting at redline, she s got lots of power, but after a couple mins of constant abuse, she feels bogged down. Plus my mileage has been crappy lately, i barely see 400km to a full tank, right now im at 160 to half a tank of gas, i use 89 octane all the time.
Im gonna get the engine scanned in, and if the o2 shows up again, what could it be making this sensor fail on me regularly?? It has the original cat, thats my guess.
The engine has 193k km.

Guest

NYC GXE,

My car idled properly and ran fine at highway speeds it just didn't have any power after it warmed up. When I tried to accelerate from either a stop or when trying to pass someone it felt sluggish.

If can not tell any difference with or without the O2 sensor connected, then it's a safe bet that you have a bad O2 sensor. Your O2 sensor is used all the time, not just when idling. You may have this confused with the idle air speed solenoid. Idle air speed solenoid should not affect power. A bad idle air speed solenoid/stepper motor would
give you a rough idle.

Found this on the web, this may help diagnose if you have an O2 sensor problem......

"Test O2 Sensor voltage output and response time with a propane torch and a digital volt-ohm meter, with 10 meg-ohm impedance in the volt meter circuit. Hook volt meter to both wires of a two wire sensor and to the single wire and to the shell of the O2 Sensor on a single wire type. Clamping the one wire sensor in vise-grips and hooking the volt meter lead to the pliers saves the fingers. Heat the O2 Sensor with the torch and observe the volt meter. You should see the voltage climb to .6V in 15 Seconds, then on up to .8V in the next 45 seconds. Remove from flame and voltage should drop to less than .2V in less than four seconds. Repeat this test two more times in succession. If it meets the voltage and time specifications, then this indicates the O2 Sensor is capable of communicating with the computer and giving fast and accurate air fuel ratio information. The faster the O2 Sensor responds, the faster the computer makes corrections."

Here's a link with some more O2 sensor info...

http://www.kemparts.com/tt07/tt07.html


TRBO,

It's my understanding that things like leaded gasoline, some silicones (used for sealing the gasket type), and some lower end fuel additives can damage the O2 sensor. If you've made modifications to your engine recently and silicone was used instead of gaskets to seal connections the silicone could potentially damage your O2 sensor. If you are using silicone(s) make sure they say "O2 and catalytic converter safe".

If your car has 193K on the original cat then you might want to have it looked at. A clear indication that your cat is clogged is if under normal operation your exhaust, particularly the cat, gets red hot. It's not unusual for your exhaust to get red hot when pushing your car to the limit, but that should not be the case under normal driving.

Guest

NYC GXE,

My car idled properly and ran fine at highway speeds it just didn't have any power after it warmed up. When I tried to accelerate from either a stop or when trying to pass someone it felt sluggish.

If you can not notice any difference with or without the O2 sensor connected, then it's a safe bet that you have a bad O2 sensor. Your O2 sensor is used all the time, not just when idling. You may have this confused with the idle air speed solenoid. Idle air speed solenoid should not affect power. A bad idle air speed solenoid/stepper motor would
give you a rough idle.

Found this on the web, this may help diagnose if you have an O2 sensor problem......

"Test O2 Sensor voltage output and response time with a propane torch and a digital volt-ohm meter, with 10 meg-ohm impedance in the volt meter circuit. Hook volt meter to both wires of a two wire sensor and to the single wire and to the shell of the O2 Sensor on a single wire type. Clamping the one wire sensor in vise-grips and hooking the volt meter lead to the pliers saves the fingers. Heat the O2 Sensor with the torch and observe the volt meter. You should see the voltage climb to .6V in 15 Seconds, then on up to .8V in the next 45 seconds. Remove from flame and voltage should drop to less than .2V in less than four seconds. Repeat this test two more times in succession. If it meets the voltage and time specifications, then this indicates the O2 Sensor is capable of communicating with the computer and giving fast and accurate air fuel ratio information. The faster the O2 Sensor responds, the faster the computer makes corrections."

Here's a link with some more O2 sensor info...

http://www.kemparts.com/tt07/tt07.html


TRBO,

It's my understanding that things like leaded gasoline, some silicones (used for sealing the gasket type), and some lower end fuel additives can damage the O2 sensor. If you've made modifications to your engine recently and silicone was used instead of gaskets to seal connections the silicone could potentially damage your O2 sensor. If you are using silicone(s) make sure they say "O2 and catalytic converter safe".

If your car has 193K on the original cat then you might want to have it looked at. A clear indication that your cat is clogged is if under normal operation your exhaust, particularly the cat, gets red hot. It's not unusual for your exhaust to get red hot when pushing your car to the limit, but that should not be the case under normal driving.

NYC GS4

iTrader: (2)

This is exactly what my car does, its perfect on the highway at high speeds, and idles perfectly but its a dog from a stop light or like you said to pass someone say when someone is turning left or double parked, its got a 20 second 0-60 pickup. I have new ignition wires, plugs, fuel + air filter, brakes, exhaust studs, motor mounts, and yet it still feels like a dog sometimes( I listed all those things because its mechanically perfect except for this sluggishness), I'm definitely gonna order the 02. Thanks for the input.

trbo

well the max passed emissions, so according to the readings, the o2 sensor is working properly and is not faulty. It passed by the way!! woo hoo. My next guess is maybe the tire width, i have 215 width tires on the max, they are the cheap *** goodyear rs-a's that come on the 96cand up,, 215 55 16. so that may be one factor in the mileage, another could be the thermostat, even though the engine temp gauge is always at the samme point, summer or winter, it could also affect mileage.
I ll figure it out sooner or later.

DavidMaxum

I am pretty sure the canister is the charcoal cannister that filters your unused fuel before it is rerouted back to your fuel tank. If you were to have a bad line to this unit it could explain some of your poor mileage. I would have thought that a strong odor of fuel would be present. I may be wrong let me know.