Y2KXCLAN

Ok I ran a diagnostic OBD II on my car because my service engine light came on. I am using Premium fuel, have K&N Air filter{in stock air box, made for maxima} with 2,000 miles+ and Bosch Platinum +4 plugs{3,000 miles aproximately}.

The Engine has 74,000 Miles on it.
I know a Lean engine can cause a Engine to run hot. And I know it means I have too much Air or too little fuel. But what do you guyz supposse is causing this? Need to run high dollar fuel injector cleaner? Fuel filter dirty? Fuel Pump going out{unlikely}?

P0171

any recommendations? i would greatly appreciatte and Thanks very much in Advance.

unrealii

iTrader: (8)

I would check for vacume leaks

This site has a few other things you can check: http://www.visi.com/~rhanson/obdII_codes-full-text.htm

TZapper

It's somewhat not connected to your problem right now, but next time you change your spark plugs, get NGKs and forget Bosch. Bosch is not designed for japanese cars and I have heard too many negative stories about running these Bosch plugs.

VMaximus02

iTrader: (1)

You should change the Bosch sparkplugs at once!
They got to be the worse sparkplugs if applied to the Maxima's or any Nissan's vehicles. FYI: I had them plugs installed in my sister 95' Max a few years back and the car just acted weird. Initially, there seem to be some additional powers but then the idle got weird the next day. It fluctuated constanstly especially when cold. There were also lots of hickups and fuel economy was extremely poor. After a week, I took them out and replaced w/the NGK's plugs. The car was at norm again.

You should stick w/OEM's plugs which is NGK brand. Another option would be the new Denso Irridium plugs. I have them in my car currently and so far so good. The car seems to rev up much smoother and gas mileage is very good.

DonGfun

iTrader: (19)

I have the Bosch Platinum +4 plugs for 10,000 miles no problems ... bad gas milage for 3 tanks but now its great got 24mpg off the last tank

VMaximus02

iTrader: (1)

Bosch must had obtained licensing right from Torquemaster sparkplug company. I used to have these on my 90' Sentra and it performed quite well. But when I installed it in my mother 87' Maxima and my sister 95' Maxima, the outcome weren't great. Initially, there were improvement but I think the computer can't compensate for the spark pattern of the vehicle.
Since my Sentra's engine was a single throttle body...not much ECU's intervention, the performance was great. FYI: Check out their site. This is their product market oversea.

http://www.torquemaster.it/main1uk.htm

Raven

OMG, I posted about this about a month ago and barely got a response to the same problem!

I recently replaced the spark plugs, NGKs, and I never thought this would be related to my SES problem. I too have the stillen intake, but I also have a greddy evo exhaust on the car.

I get the same EXACT code as you and it sounds like the same behavior. My idle is rough and it sounds like its about to stall, but then revs up to 1500 and back down.

My buddy, who is a mechanic, said that this may be the O2 sensors that are now *beginning* to go bad, but I won't know until I replace them. I have 76,000 on the car and I have also noticed that after I ride the throttle hard, I get the rotten egg smell.

I will be replacing the O2 sensors (I'll be so ****ed if this doesn't correct the problem) and I'll let you know if this route corrects the problem. Otherwise, I won't pass emissions!

DanL

Just a thought -- over-oiled K&N filters have resulted in many premature MAF failures, and yes, a bad MAF is one of half a dozen or so possible causes listed in the FSM.

Raven

I should have mentioned that I am also replacing the MAF since I found a gd in another post from some online nissan store. That was another component that the mechanic said could be failing and I'm sure I overoiled that filter at some point. I'll let you know the results of replacing the O2 sensors AND the MAF.

bobby.cim

I have had the same P0171 code on and off for a while, I changed the MAF to no avail. So if anyone who HAS the code and FOUND a solution can u post it. I checked the site for the codes and there are like 20+ possibilities. Thanks

Y2KXCLAN

This apparently is a semi common problem as i see a few others have ran into this.
I guess we should all share our successful and failed attempts and maybe we can help each other out. I will defineately post a solution if I find it. Hopefully we can fix this.

Btw the K&N was factory oiled...but maybe they oiled it too much?
I was going to look into prices of O2 sensor and MAF sensor ...any idea on where good prices are? Also I may go ahead and change the Plugs allthough the car seems to be running flawless.

Raven

hey guys,

I have solved the P0171 dilemma and it was indeed the MAF. The code thrown is completely inaccurate, but before we replaced the O2 sensors, I did the $83 MAF from an online Nissan parts store and my max runs like its brand new. I highly suggest a new MAF if you have this problem!

Y2KXCLAN

I just had the mass air flow sensor replaced and the light went away...no more codes. hope this helps out at least 1 person.

Rich1

I too got 2 codes actually:

P0171 - system too lean (bank 1)
P0174 - system too lean (bank 2)

Just replaced the MAF, PCV valve and cleaned the throttle body while I was at it...I took the negative terminal off the battery while I was doing this and when I was finished the SES light went off (ECU reset I guess) and hasn't come on since.

Hope this helps too....Thanks Dave B from Southpoint Nissan for the updated MAF!

Y2KXCLAN

ok so I lied, check engine light is on again....sigh* dont have the tester....gotta rent it.

dentonmax00

I had the same codes. I replaced the O2 sensor and haven't had any problems since. My car ran fine though while the SES light was on so yours may be different.

y2KAOSMax

Where you get your O2 sensor from and how much??

[maxi-overdose]

iTrader: (3)

fuel injectors shoots fuel to your engine and they are controlled my MAF sensor. so....it can be

1.intake air leak after MAF - some air was not measured by the MAF sensor, resulted in "too much air"

2.dirty fuel injector - decrease of fuel delivery = too little fuel

3.O2 sensor - your air-fuel is measured by O2 sensor. a bad O2 sensor can cause the same problem.

4.fuel pump, fuel filter, etc - do you experience hesitation in your car?




dont spend money on any parts. find out what causes the problem first or eliminate as many as possible. I would:

1.check spark plugs make sure that it is not running lean. if you are running lean, your plugs will look really white. if your plugs do not look lean, that means your O2 sensor may be the cause because it is not measure correctly.

2.check for air leak after MAF

3.Test your MAF with a multimeter - a healthy MAF should have a stable voltage ready during idle and raising voltage when open the throttle. I dont remember the idle reading and the max volt. reading.

4.check fuel pressure with a fuel pressure gauge and make sure the fuel pump or fuel filter is in good shape. follow Hayne's manual and the fuel pressure should not fall below 34psi during idle. pinch the fuel line between the gauge and fuel rail to see if the pressure goes up. If it drops, it means the fuel pump cannot provide enough flow. Hayne's manual has a few more tests you can do to test your fuel pump.


good luck.