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Discussion Starter · #1 · (Edited)
So my v6 tib is throwing a code for p0150.
it has thrown a short lived CEL for this code like 3 times in the past week but the code never goes away.
I know the code is for o2 sensor (bank 2 sensor 1)
but checking my o2 sensors through my obd, this sensor works just as the other o2 sensors do.
I saw elsewhere that this code could also mean a vacuum leak but my hoses are all fine..
is it possible my obd scanner is lying to me?lol

I know something is up because I have times when my acceleration seems inconsistent when I push for power in low gears.
kind of like hesitation I guess, but at 3.5k rpm instead of at takeoff (or is that still hesitation?)

should I go ahead and replace the o2 sensor anyway.
 

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The upstream O2 sensors are different than the downstream. your down stream sensors should be at around .45v steady, upstream sensors rollercoster up and down from rich to lean to feed the cat.

I would suggest checking the harness on that sensor. Check for burn marks, or water in the conncetor.
The other thing to do is, if you have a scan tool with live data, with the engine idling, unplug a vacuum line briefly and watch the sensor data. It should go full lean. Luckily number 1 is easy to replace, just make sure you get the right sensor. Good Luck! :)
 

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Discussion Starter · #4 ·
so i replaced that o2 sensor, (it was a relatively new bosch sensor that was totally fine according to my multimeter)
but i replaced it anyway with an expensive ass OE replacement. and it worked... kinda..
my cel went away and the car runs a little smother and passed emissions (finally)

but when I checked after replacing the sensor and after the emissions test I was still coding for p0150.
and it wasn't just my obd2 android scanner, an expensive mechanics scanner also picked up the code.
also my fuel trims 1x1 and 2x1 are both reading constant 99.2% while the others are normal.
shouldn't all of this have been fixed with the o2 sensor replacement? especially if i passed emissions?
any advice?
 

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What trims are you looking at? Usually Long terms top out at 25%. If your trims are that high I would say let's start by checking for vacuum leaks. I usually use water in a spray bottle. You could use MAF cleaner, it's just more expensive. Are you using Torque Pro, OBDLink?
 

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Discussion Starter · #6 ·
What trims are you looking at? Usually Long terms top out at 25%. If your trims are that high I would say let's start by checking for vacuum leaks. I usually use water in a spray bottle. You could use MAF cleaner, it's just more expensive. Are you using Torque Pro, OBDLink?
the trims are fuel trims 1x1 and 2x1. still trying to figure all of that out but I read somewhere that it was related to my o2 sensor problem, and that if its higher than 25% its either an error or a huge problem.lol

I use Torque on android with a Bluetooth obd2 elm 32 thing.
but I will try the water spray to check for leaks, good tip!
 

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Or you can use starter fluid and spray around all your seals to check for a vac leak, you will get a jump in rpms when you find it. How is your idle? Smooth? and what does it idle at? A rough or high idle means a vaccum leak.

It's possible it was a combination of the sensor and maybe a bad harness, have you stripped back the loom and checked the wires?

And to bank off what Tibutrama said if your trims are +25% then you have a lean condition which can be the result from headers install, vaccum leak, cai install. Anything that the computer sees a bunch of air then fuel and it will add it in to compensate.

I had a similar condition when i installed my headers, i didnt have a vaccum leak (at elast i didnt think i did) but my trims were @ 22-23% I used my NEO to add 10% so my trims were 12-13. Thus not causing my CEL. This was a bandaid fix as i new something was off. I resealed my entire engine when i put the blower on and i have the best readings of trims and vaccum i ever had. To be honest the supercharger has made the car run better then it's ever run strangely. Maybe i had vaccum leaks all along until now.
 

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This is the way I look at it.....

Fuel trim is a system of measurement the ECU uses to bring the engine as close to stoichiometric ratio as possible.

Long term trims are going to add fuel if there is pirate air coming into the engine (vacuum leak). Normal LTFT hovers anywhere from 0-25 percent. I personally am not concerned of anything under 8%.

Short term trims normally fluctuate rich to lean in order to feed the cat converter the gases it needs.

On your Torque app, ad 2 gauges for "Fuel Trims Long Term" for both banks. In Torque the LTFT is not going to exceed 25%.

The first bank of O2 sensors should be fluctuating up and down. The bank 2 O2's should be pretty steady at around 0.4V to 0.5V.
 

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1-How much running have you done since the sensor replacement?
2-Did you clear the CEL or disconnect the battery after the sensor replacement?

What I'm getting at is, if the trims were out of wack due to a bad sensor, you may not have enough drive time to let them settle in to the new sensor.
 

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Hey Guys and Gals! (politically correct)
Does anyone have advice about what brand of O2 sensors to use in my 05 Tiburon SE V6? Greatly Appreciated!
Our ECMs are very finicky about sensor brands so make sure you use NTK for best results. I've heard rumors that Mando and Denso work too but I don't have experience with them. Other reputable brands like Bosch will not work correctly.

Also for the year 2005 you need the 1Volt variant so don't get those mixed up with the early 2002-2003 5Volt variant.
 
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