Just me guessing, but would i have a bad o2 sensor? Isnt there 2 of them? Would/Should i replace both? How can i tell which one is bad?

Thanks,

Shane

 

Okay I browsed over your whole thread on tuners, and you had a lot of good suggestions on there.. I know it can be frustrating but lets take a step back.. Explain to me exactly how you did your boost leak test, I know you hooked it up to the turbo inlet but where you using a decent size air compressor? Do you have an aftermarket boost gauge and did you watch the boost gauge as you pressurized the system?? You should be able to pressurize your system to 15-20psi because I doubt your running any higher than that and it should build up to that on you boost gauge and then slowly fall off! If your not building boost on your boost gauge to your desired boost level then there lies your problem, you still have BOOST LEAKS! If you think you've fixed all your boost leaks from the intercooler pipes/cuplings then put the intake back on and boost leak test from the throttle body. Make sure your t/b isn't still leaking and your intake manifold, injector seals etc... If all this checks out the let us know but you have to be thorough because the leaks can be very hard to find sometimes..

Just me guessing, but would i have a bad o2 sensor? Isnt there 2 of them? Would/Should i replace both? How can i tell which one is bad?

Thanks,

Shane

Yes, you very well could have a bad o2 sensor but make sure the free stuff checks out first.

If you do end up buying a sensor and you plan on tuning your car I would highly suggest a wideband o2 sensor/gauge because you can use it in place of your rear sensor and get rid of that pointless narrowband o2 that you have.

 

We got up to about 12psi and my boost leak tester would blow off. We are trying to get a tighter fit. But it made it to that without leaks. Yes i have an aftermarket boost guage. But the leak from the TB was from my BISS i believe. If not, i will replace my TB seals. Ill try the boost leak test again.

Once i get the bigger turbo in my car like planned, ill invest in a wideband. But for now, my narrowband is going to have to do.

Shane

 

I was just saying that as an alternative to buying two new o2 sensors if it comes to that. Post up your results when you get ALL the boost leaks fixed, but your probably right.. It does sound like it could be an o2 sensor going out. Just FYI, a t-bolt clamp will help with the cap popping out.

 

Oh i see. Would it be cheaper to get the wideband system? And its not the cap that blows out, my tester itself is rock solid. It just comes shooting off of the turbo. Scared the s*** out of us the first time

Shane

 

Just FYI, a t-bolt clamp will help with the cap popping out.

+1
T-bolt clamp FTW

 

How exactly can you tell that you're running rich?

 

My A/F Guage says i am. Not to mention my gas mileage is worse. I dont think the problem is a boost leak. Because i seem to run not as rich when im building boost. And the boost always goes up and holds. I think my leaks are taken care of. Would it be cheaper to get a wideband or to get 2 new o2 sensors?

Now my car when i start it, it acts real weird. Like its bogged down and it jsut spits and sputters for a bit then runs normal. It does this in low RPMs. Any ideas? This just started today...

Shane

 

I still think you need to test it to at least 15psi from the turbo inlet and the t/b.. A boost leak might not be your problem but I garantee you still have some, your probably just overlooking them..

The two o2 sensors would be cheaper, but just for future reference, you might as well not even look at that narrowband a/f gauge because it really is pointless. Besides, these cars run rich stock anyway..

If possible it might help us get a better understanding of what your talking about if you put a vid clip up.

My A/F Guage says i am. Not to mention my gas mileage is worse. I dont think the problem is a boost leak. Because i seem to run not as rich when im building boost. And the boost always goes up and holds.

Shane

Like I said above there's no way you can tell you running rich at wot because that gauge doesn't tell you shit.. As far as the boost going up and holding, that doesn't mean anything either, you could still have leaks!

 

Well my A/F guage used to bounce back and forth like it should. Thats when it was running "normal". Then it just stopped. a 1/4 tank used to get me about 80 miles. Now it gets me 60.. The only time it got me 80 miles for a 1/4 tank for the way im running now, is when i drove around at low speeds and nothing passed 3k rpms.. But its a DSM, you cant expect me to drive slow everywhere

Shane

 

Yeah, if you're looking at a light-show gauge (narrowband A/F gauge), I dunno how you're actually making sense out of the readings. I hooked one up and all it did was bounce back and forth and annoyed me to death. My car smells like it runs rich, but now I'm putting a 16G on it and it'll probably be running lean until I can afford some injectors and a tuning device.

 

The narrow band af should cycle, rich lean rich lean. I doubt the problem is the o2, the rich indication it is giving you is probably a side effect of another problem and if your o2 failed rich then your car would run lean. So I would check 1.ect tend to go bad (a badengine coolant temp sensor=pig rich) 2. the wiring for you s-afc, specificaly the wiring for the maf but check it all wirring since i think there is an ect wire and if it had poor power/ground it could affect the mas/maf reading sent to the ecu. 3.Wiring for you maf/mas and the maf itself for functionality.

other rarer problems could be a fpr that is stuck closed so you have way too much fuel pressure, to test just take off the vacuum line that goes from the maifold to the fpr and the idle should change, if it doesn't then it is likely not opperating properly. A clogged/kinked return line could cause simmilar problems.
If none of these are the problem get back to me and Ill have some more ideas for you

 

Good point, for some reason I thought the o2 sensor being bad, "would cause a rich condition.." Learned something new, sorry to the op for mis info.

Heres some 02 info that I just read

DERIVABILITY SYMPTOMS

An O2 sensor's normal life span is 30,000 to 50,000 miles. But the sensor may fail prematurely if it becomes clogged with carbon, or is contaminated by lead from leaded petrol or silicone from an antifreeze leak or from silicone sealer.

As the sensor ages, it becomes sluggish. Eventually it produces an unchanging signal or no signal at all. When this happens, the Check Engine Light t may come on, and the engine may experience derivability problems caused by an overly rich fuel condition. Poor fuel economy, elevated CO and HC emissions, poor idle, and/or hesitation during acceleration are typical complaints.

If the average voltage from the O2 sensor is running high (more than 0.50v), it indicates a rich condition, possibly due to a bad MAP, MAF or Air Flow sensor or leaky injector. If the average voltage reading is running low (less than .45v), the mixture is running lean possibly due to a vacuum leak or because the O2 sensor itself is bad.

If the O2 sensor continually reads high (rich), it will cause the engine computer to lean out the fuel mixture in an attempt to compensate for the rich reading. This can cause lean misfire, hesitation, stumbling, poor idle and high hydrocarbon emissions (from misfiring).

If the O2 sensor continually reads low (lean), it will cause the engine computer to richen the fuel mixture. Injector pulse width will increase causing fuel consumption and carbon monoxide emissions to go up. Constant rich fuel mixture can also cause the catalytic converter to overheat and it may be damaged.

If the O2 sensor's output is sluggish and does not change (low cross counts & long transition times), the engine computer will not be able to maintain a properly balanced fuel mixture. The engine may run too rich or too lean, depending on the operating conditions. This, in turn, may cause derivability problems such as misfiring, surging, poor idle, and high emissions.

"I guess there is somewhat of a function for a narrowband, if your light show stops fluctuating between rich and lean, you know somethings not right.. "

 

If the average voltage from the O2 sensor is running high (more than 0.50v), it indicates a rich condition, possibly due to a bad MAP, MAF or Air Flow sensor or leaky injector. If the average voltage reading is running low (less than .45v), the mixture is running lean possibly due to a vacuum leak or because the O2 sensor itself is bad.

If the O2 sensor continually reads low (lean), it will cause the engine computer to richen the fuel mixture. Injector pulse width will increase causing fuel consumption and carbon monoxide emissions to go up. Constant rich fuel mixture can also cause the catalytic converter to overheat and it may be damaged.

After reading over this again it says that if the voltage reading is low"lean" it could possibly be a bad o2, then it says if the sensor continually reads low the ecu will richen the fuel mixture, so if his assumption is correct in running rich then why couldn't it be an o2 sensor?? Not saying that is his problem just wondering if its a possibility??

 

If his o2 sensor is stuck lean then it could be a bad o2, and easy way to check this is to take off one of the vacuum lines and run some propaine in there, if the voltage does not come up then the o2 is definitaly suspect and most likely bad.