i30ds

iTrader: (8)

After 2 1/2 years of ownership my i30 finally had its first mechanical problem. A few days ago, I got a CEL! I ran a self test on the ECU and got codes 0304 (knock sensor) and 0115 (fuel injection system running lean). I wonder if this could be a case of one thing causing the other?? I used my multimeter on the KS sub-harness and there was continuity (about 4.5 ohms) there. I don't even know where to start with the fuel injection system, it could be so many things (injectors, intake leak, oxygen sensor, MAF sensor, fuel pressure)!! I replaced the fuel filter not but 5k ago and used a can of quality injector cleaner last fall and the car still runs smooth and fine. You guys got any ideas??

I30tMikeD

iTrader: (8)

How is the car running? hesitation etc.....

i30ds

iTrader: (8)

No hesitation, and it fires right up!

flthere

iTrader: (2)

Probably needs fuel injection system cleanup that will get rid of the knocking as well ...

I30tMikeD

iTrader: (8)

Well, I would definately not start replacing expensive injectors or the MAF yet. I would first start by listening to all your injectors. You can use a automotive sethascope(sp?) or a long screw driver. Place the screw driver on the injector and put your ear up to the handle end. Make sure all the injectors sound the same. VQ30de injectors are really loud so it should be easy to tell any differences. Also check the voltage of each injector, parameters and instuctions can be found in a haynes manual.

Clear the codes, get some good fuel system cleaner and see if the codes come back. If they do then look to maybe replacing the knock sensor. You said the knock sensor sub-harness was within the correct parameters, but that is the sub-harness not the knock sensor.

i30ds

iTrader: (8)

Well the chiltons manual says that if conituity exists on the KS sub harness, the the sensor is fine. However my reading of 4.5 Mohms is not with in the 500-650 kohms that were described as the appropiate amount in the 4th gen sticky thread. So, going on a hunch that one thing is causing the other a replaced the KS today. I cleared the codes, and took a test drive. After about 10 miles or so I got the CEL again!! I ran a self test an although the 0304 KS code was gone the 0115 code was still there!! Crappy chiltons does not have instructions for testing the fuel injectors or their parameters. I will attempt to carefully listen to front injectors, but the rear ones will be extremely difficult to do because they are underneath the intake manifold, and that is the bank that is running lean according to the 4th gen ECU code sticky. I really really do not want to remove that manifold! The car still runs perfectly fine.

I30tMikeD

iTrader: (8)

Oh, I read it as 4.5 = 4500....yhea, that is not good.

I was totally wrong about the knock sensor harness thing....I have even checked it that way myself, I don't know what I was thinking when I typed that.

I have an MEVI, but can reach the rear injectors with a long screw driver....don't know about the stock manifold. I am sure you could at least get to the outer ones.

My haynes says 10-14 ohms of resistance between the two terminals for the injectors.

i30ds

iTrader: (8)

Thanks. I tested all of the injectors, except #3 (the one behind the intake manifold in the middle), and all measured exactly 12.5 ohms of resistance. So no problem there, unless it is #3. They all sound the same too. I bought some high quality injector cleaner, reset the code, and 20 miles into a test drive, right when I though I was in the clear, it came back again!! I then tested each oxygen sensor as directed by the chiltons manual, and they had 4.1-4.7 ohms (parameters of 2.3-4.3 ohms) of resistance. I am some what skeptical of these results. As you may recall, the chiltons method of testing the KS was acutally 100% incorrect, and if it were not for the sticky giving me different instuctions, I would not have replaced it. I am having a hard time finding any useful thread pertaining to oxygen sensors. What does the haynes say about testing the them?

I30tMikeD

iTrader: (8)

I will do a search for you on this particular problem. I am about to head out for the night, but I will report back when I get home or in the morning.

I30tMikeD

iTrader: (8)

http://forums.maxima.org/showthread.php?t=297811


http://forums.maxima.org/showthread.php?t=104193


http://forums.maxima.org/showthread.php?t=37480


Not a whole lot of info. From some posts it seems that the 0115 code usually comes with a bad o2 sensor code. Being that the a bad o2 sensor will cause the 0115 code. You might want to try replacing the o2 sensor for the rear bank and see if it solves the problem. They are easy to replace and can be bought for $60 or so.

i30ds

iTrader: (8)

Thanks for the threads! According to one of them you must test the oxygen sensor by not checking its resistance in ohms, like chiltons says, but rather test its voltage and see if it goes from .2 to .8 up and back down again in wave patterns to constantly check for rich or lean conditions. I asked a friend who has a factory shop manual, and it says the same thing as the thread. I tested each of the o2 sensors in this manner and to my suprise two of them were not even showing any voltage at all!! The third was very slow.... it would mostly stay around .1 and shoot up to about .3 and then drop to 0 and then sit at .05 and then jump around some more. So it looks like all of my o2 sensors are shot! I dont know why I did not get a CEL code for each oxygen sensor, but I will replace them and clear the codes. Hopefully I wont get another CEL again.

As soon as I get the cash, I am going to buy a factory shop manual!! chiltons was 100% incorrect on the correct way to test both the KS and o2 sensors. Also, it says the KS is under the exhaust manifold on the VQ30de engine . I will burn it!!! It is going to be a few days before I get my new o2 sensors, but I will post after I do the repairs. Thanks again for all the help!!

I30tMikeD

iTrader: (8)

No problem. I am always willing to help those who will help themselves

i30ds

iTrader: (8)

I put my new 02 sensors in on Friday and reset the ECU, and it has been about 40 miles, and no CEL so I think the problem has been fixed.

Thanks again for all your help.