Can over-gapped sparkplugs cause a lean condition?

 

No

Check for a vacuum leak, clogged fuel injectors, low fuel pressure.

 

I gotta disagree NJ man,

If clogged or burnt plugs can cause misfire, than so cant improperly gapped plugs. Im talking grossly overgapped plugs.

 

So can ****ty non-pregapped Non-NGK plugs

NGK. Always.

 

I put in NGKs two weeks ago, but I did not check the gaps like a dumas noob that I am and this code has been popping up. She runs well though, which is odd. I'll check the gaps, see if that helps.

I went for an inspection today, and the mechanic told me she's running rich just by taking a whiff of the exhaust... ECU came up "Not Ready" despite 100 miles of driving after reset. I hope gaps are my problem.

 

Does lean = rich? As in 'lean on gas' = 'rich in 02?'

 

I know that the plugs come pre-gapped but I don't see why this would cause you to run lean. Did you have this problem before changing the plugs? CEL?? Most plugs these days do not need gapping and can be installed without problems...unless dropped. Did you put them in with the right socket or did you drop them in and then screw them in?

 

I had a couple of different codes but not the 0115; one code for rear 02, and one for CKPS, both of which have cleared after replacement and cleaning respectively. I did not have the right bank fuel inejector lean CEL until this morning. I put the plugs in a socket first then put them in. I'm going to take them out and take a look at what's up. I also ordered something called the insulator air duct that goes after the MAF housing on the intake, and before that resonator assembly on the intake. It's a bit rotted and crumbling and may be leaking, but I keep thinking it's the plugs.

I'll get this done soon because I need the inspection sticker, so I'll be able to let you know what the reason was for the 0115 (It comes on really late after an ECU reset too. Not an immediate CEL like one often sees after resetting)

I still don't know if lean = rich.

 

Running lean means that you have more air than fuel mixing together...

 

Well, then why did the mechanic tell me I'm running rich, just from the smell of the exhaust? Should I even trust that?

The ECU is saying I'm running "lean." So I'm a bit confused.

Anyway, I got 2 spark plugs out of the rear banks, checked the gap, it was good on those two: .04 on the dot. I still have the other 4 left to check tomorrow (it got too dark).

I tightened up the air insulator duct next to the MAF. It has cracks in it, and the air filter was dirty, so maybe the car started sucking air through those cracks since there was a lot of resistance from the air filter. That's why it took 90 miles or so for it to trip the CEL; it wasn't much of a leak. I'll ride this until I get the new air insulator.
So far it's >130 miles and no CEL, so fingers crossed.

Thanks for the help so far.

 

Yeah, so I just went 450 miles, no CEL, and the ECU is still not ready to complete an emissions test; I hooked it up to a reader, EGR and EVAP were both blinking indicating they were not ready, and although no CEL is thrown the reader says P0171 code still popping with a "lean bank 1," so this is the 0115 originally posted...

Replaced the air insulator duct, if it was letting in too much air this new one should fix it.

And, I cleaned the EGR today, it had deposits but it was not blocked. Wow, what a pain in the azz job, if you don't have the right tools you'll be steaming pissed. 12mm open ended, 12 mm ratchet wrench, short and long, and one-hand sawz-all may have you out of there in an hour. And that's just for the EGR portion of the job.

Narrowing down on that 0115 hopefully.

 

By the way, she runs really really well, so I am not sure what is up with this code shyt. Starts and runs like a new car.

 

Check for vaccum leaks (disclaimer: only skimmed the thread) Just spray carbcleaner or starting fluid around your engine bay and if the idle changes you have a vac leak, make sure all your hoses are tight as well.

 

What trick is this? So carb cleaner gets sucked into the vacuum leak hole and the engine burns it? What is starting fluid?

 

usually the ecu will compensate for a lean mixture by richining up the a/f ratio. lean=holes in pistons rich=badfuel economy i would check to see if your o2s are responding slow. take a clip board and put it over your air filter (you must do this with a scantool) and check if your mixture goes rich immediatly. if not replace the sensor. also try to smoke test your intake and exhaust, this will find any holes anywhere. a hole in your exhaust (header gasket, y-pipe gasket, etc.) can cause a lean mixture keep me updated.

 

Yeah, if theres a leak somewhere from either a hose or the manifold ect.. it will suck it in and the ecm will compensate for the extra fuel thus chnging the idle.

starting fluid is usually for people with hard starting engines.. its just some extra fuel to burn.

 

Did the break cleaner spray trying to get all the obvious air line linkages, and intake gaskets, manifold gaskets, under the manifold on the rear bank, all while the engine was idling: there was no tell-tale idling difference.

I do have a leak on the camshaft sensor, which is spewing oil because I did not replace the o ring when I cleaned it, but I am not sure if that could be causing the 0115 problem. I'll fix that on Tuesday if the local Nissan dealer has the o-ring.

Still chasing the 0115 code. I actually got the official CEL after 517 miles of CEL free driving. That was just, disappointing. The car is stock. The engine runs like a dream too; it starts like a new car, like a friggin' champ actually, the RPM does not drop to 500-550 when at red lights, it's steady at about 750 whether in D or P. It's perfect other than this 0115 bullshyt.

I hope it's not an exhaust head leak because that just sounds like trying to get broken bolts out of the block, and goodness that would just blow chunks. Wouldn't know where to begin. I would stick something on the hole just to pass this emissions bull.

I have not tried the clipboard approach because I don't have a scan tool at home.... I'll try to see if I can do it at Advance Auto parts. I'll update.

 

Front heated oxygen sensor (right bank) - I HAVE TO PULL THIS ONE, WIPE IT OFF AND PUT SOME AIR ON IT, SEE IF THAT HELPS
Exhaust gas leak - MAYBE


X Intake air leak - NO (probably), BREAK CLEANER DID NOT SHOW A VACUUM LEAK
X Injectors (right bank) - NO, THERE WOULD BE OTHER SIGNS, CAR RUNS GREAT
X Lack of fuel - NO SIGN OF THAT AT ALL
X MAF sensor - NAH, CLEANED IT, CAR RUNS GREAT

 

I would really appreciate it if someone told me if the hissing sound near the IACV when the engine is running is normal. This 0115 code has me paranoid about every sound in the engine bay.

Well, just replaced the PCV grommet (what a little bytch). Had to wait a couple of days because dealerships don't stock them - which may have something to do with the condition it was in. Anyway, it was old and falling apart, had to use a coat hanger to get it out without the bottom half falling in the rear valve cover.

I am crossing my fingers this grommet was the vacuum leak, as someone else had this same CEL and it was the PCV grommet.

Currently 120 miles after reset, no CEL. Must get this inspection passed.

 

mine doesnt hiss i have a cai so i here the air getting sucked in by the filter i think you should check all the rubber hoses around the iacv you possible have a vacuum leak

 

Well there is a slight hissing sound near the EVAP valve on the UIM. Not the IACV, as I just changed that gasket and applied RTV just to make sure. I'm starting to think the slight hiss is normal and coming from the EVAP valve.

I am still showing P0171, or 0115, checked it at pepboys and although the CEL was not lit, it was a pending code on the reader.

I changed the rear bank 02 sensor today, we'll see if that does it. Try that with an adjustable wrench LOL.

It may end up being the injectors as this is a high mileage car.

Unfortunately I don't have a code reader handy at home to try simulating a lean condition, like the clipboard method suggested above, to see if the O2 bank one reads lean right away. I've seen two mechanics use the Equus readers, one said he had his 3130 for 3 years and it has not crapped out yet (1 year warranty), another had a 3160 model. I want one.

Anyway, I will keep updating my thoroughly unscientific way of solving this CEL. Note to self: get a multimeter. I am thinking Equus $20 auto-ranging one from amazon.

 

Is there anyway for you to get us a video of this hissing noise or some sort of voice recording? That would be helpful but as I recall, there should be no hissing sound...

 

This is another .org member video of a ticking in the IACV, but in it you can also hear the hiss when he moves the camera closer to the IACV. That is the slight hiss I am talking about.

http://www.youtube.com/watch?v=SNIYTLbsVto

 

I hear it but its barely noticeable...I will rule that out as normal and will not cause your lean condition.

 

I am still getting the P0171 code (0115).

So far I've changed

O2 sensor
PCV & grommet
MAF insulator
cleaned IACV, replaced gasket, RTVd
EGR tube cleaning (maybe this thing is leaking)


I've sprayed with TB to find the leak, no luck.

The car runs fine, so it can't be MAF or injectors. It has to be a Vacuum leak somewhere. I don't have the $ to get this thing smoke tested.

Emission sticker expired yesterday.