maximatech12

I searched the threads about my 2001 Maxima with 153000 miles on it here at Maxima.org and got a few helpful tips.
I'm trying to pinpoint where fuel could be coming into the oil from. I change the oil a few months ago and it had a strong fuel smell to it. I would assume it's a leaky fuel injector O-ring.
In another thread I read that sometimes the fuel injector could stick/stay open when you turn the car off resulting in a fuel leak into the intake. I haven't performed a fuel pressure test yet. Could the O-ring under the plenum be leaking because I don't smell fuel or see fuel around the exposed fuel injectors.

maximatech12

Maybe I need to replace the spark plugs? I haven't done that and I'm unsure whether or not it's ever been done. I haven't changed the air filter in over 3 1/2 years either. could any of these contribute to an excess of carbon/fuel smell? when I change the oil the MIL lamp goes off and then about a 6 weeks later it comes back on. I have to get an OBDII scan tool pull the exact code.

fat_kid

iTrader: (13)

:Facepalm: 3.5 years?

Do your regular maintenance, dont know about the fuel smell.

Go to autozone or something and they'll scan your car for free.

NmexMAX

iTrader: (22)

Holy ... didn't even catch that.

maximatech12

I got a scan at Auto Zone a couple of hours ago. The code was a P0430 which is a Catalyst. Makes sense because I had that one replaced with an aftermarket Cat 5 years ago. But when I change the oil the MIL lamp goes out. So I would assume it's got a little something to do with the carbon build up in the oil too. I burn 89 fuel all the time always. It's posted on the fuel door to burn premium 93 but that get's old.

maximatech12

The MIL lamp comes on during the summer but goes out as the weather gets cooler. It's usually an emissions code corresponding to the catalyst. It's an aftermarket CAT that the dealership put in under warranty.

maximatech12

I burn Mid Grade fuel. So I'm not sure exactly what octane. I'm pretty sure the pump says 89 but sometimes they have 4 different grades of fuel.
I'm planning to change the spark plugs and VCG's. I don't think it will effect the emissions though.

MadMax SE

Why not use the recamended type of fuel for the vehicle? If there is carbon buildup in the crank case then i wouldnt doubt there is some on the piston. bad carbon buildup on the piston can FORCE some people to use higher grade gas to compensate for detonation caused by carbon. carbon holds heat and can light a compressed fuel charge before the plug can causing a knock. If your car sensed knock from using the 89 it could be pulling timing and more importantly dumping more gas than it should to supress the knock which is why you could be smelling it in the oil. being that you always use 89 makes me think this theoretical dumping of fuel from the 89 killed the cats in the first place. Is a couple of cents worth the loss in power, reliability and mpg?

MadMax SE

If your plugs are carbon fouled or just plain old it can effect emissions., if there not firing properly then the motor could be spewing unburned fuel into the cat ultimately giving it a slow death. 91 or above would be a good choice...erm well......the best choice. dumping fuel and possibly bad plugs would directly lead to loss of power and gassy oil, or so i believe.

maximatech12

Thanks for the Reply! So fill up with premium? Good point. If I'm in the 5th gen maxima lounge a good thread to begin would be / what fuel do all the other maxima owners burn in their vq30k?

MadMax SE

Yes fill up with premium for now on. You should reset the ecu once you fill it up so it can learn new fuel trims and timing. There are several stickied threads at the top of the 5th gen max discussion page. Read all of them if you have the time/patience because the info could save you the future head aches. From what i know most if not all 5th gen drivers use premium gas, it what the max craves. anyone with bolton mods is guaranteed using premium.

fat_kid

iTrader: (13)

THREE AND A HALF YEARS?!

Did you not drive it at all in that time?

Do you have pics of it?

maximatech12

re : Check out my public profile I've posted a picture of my 5th generation.


Thanks for the help!

fat_kid

iTrader: (13)

Any pictures of the air filter?

maximatech12

No I don't. Maybe I'll snap a shot or two when I change it.

maximatech12

I used to change the thing so much in my last car it looked brand new every time I changed it.

So when I got this car I let it go until it showed some signs of dirt. Well that wasn't too intelligent because it created major performance issues and also my fear is it could've dumped unburnt fuel into the oil + exhaust. This is a 12000 mile filter I left in for 4 years,

Child_uv_KoRn

iTrader: (7)

Unburnt fuel will kill a cat, so that definitely didn't help it. That's why the POS ones in the 5.5 fail so easy.

Unless it is running insanely rich, then it sounds like there's a leaky injector.

maximatech12

I don't work in the auto industry and don't see a lot of car issues but what about maybe a timing chain issue ? You think maybe it's time for a new chain/guides/tensioner?

maximatech12

I drove every day on it and it was more like 5 years. I get a sputter when I start the thing I was just responding to Chil uv KoRn about s possible chain/ guide replacement Could this issue cause the fuel to smell like oil or the other way around. Honestly I thought the spitter could be fouled up plugs from leaky cover gasket / well o ring. Being in the presence of the great maxima gods it occurred to me that this is it

maximatech12

I think it has something to do with the catalyst. I have changed the air filter a few weeks ago and did an oil change and now again just aprox. six weeks after the oil change a DTC flashes. The car is now in a no start for another issue but the oil smelling like fuel/DTC code has to be a direct result from catalyst failure.
When I get it back up and running I'll check compression then change catalytic converter hopefully piston rings valves will be OK.
I think it has everything to do with what the community was saying about PreCat failure.


Thanks for the input...

maximatech12

removed old Bougies and replaced with Motorcraft Platinum

Catalyst failure wouldn't leave the oil smelling like fuel though right?
MadMax may be on the money with the plugs being bad because the car has 150xxx miles and I doubt they have ever been changed.
Typically people keep up with the maintenance so you have to ask around to someone who has witnessed the effects of old plugs that need to be changed.


"Open in new tab"

MadMax SE

I would have personaly bought the ngk plats for the peace of mind. If your air filter was that blasted with dirt, then there is no telling what your MAF sensor screen looks like. i would blast that down with maf cleaner too see if it does the trick.

mclasser

Why did you put Ford plugs in a Nissan??

In these engines, NGK or bust. There's a reason Nissan put them in at the factory.

Donkeypunch

off topic but the reason was $ money $ not performance
why does bmw go with bosch, a german plug
or ford with autolite/motorcraft an american plug.

Just saying the reason is not because ngk is the best even if it might be. It's just money.

You can't just say ferrari uses these plugs so I'm using them too there's a reason ferrari uses this. That's dumb.

MadMax SE

^^^this, but I had an occasion where when I bought my max it was misfiring so bad it was undrivabile. The previous owner had Bosch plugs just installed in it and it ran like crap and smelled like raw fuel. Ngks made it purr again but this isn't the case with everyone.

Child_uv_KoRn

iTrader: (7)

There have been several members that used bosch or w/e plug and it caused misfires/codes.

mclasser

Nissan engineers, for the lack of a better term, designed the engine around NGK's. Sure, you'll hear stories about the friend of a nephew's uncle that ran Bosch's without issue. And no, I'm not some NGK fanboy. I'm just of the opinion that since changing the plugs on our cars is a such PITA, you only want to do it once. I'm not trying to tear everything apart again since some random Bosch or Autolite plugs caused a misfire.

Derrick2k2SE

iTrader: (3)

I can't explain it but Japanese cars just run better on NGK plugs and Euro cars run better on Bosh. I don't have much experience on Domestic cars but we work on a lot of Japanese and Euro. I would never put anything but NGK in a Japanese car without a very specific reason.

maximatech12

I was going to but the parts store said Motorcraft was better quality.

I'll contact Motorcraft and confront them if I get a backfire + I'm going to install a new pre-cat after the compression test.

Maybe these members were using crappy gas? What rated octane did they fill up with?

MadMax SE

It's not that the motorcraft won't work, they just won't last nearly aslong and have a chance of fouling right up due to crappy spark. If you contact motorcraft,there just going to tell you they won't misfire and blah blah blah, oh and I believe motorcraft is fords line of stuff. I would never choke my car with a ford product.

Derrick2k2SE

iTrader: (3)

Believe it or not, there are people out there who pass them selves off as experienced but just give bad advice to people. Just because someone stands behind a parts counter or even calls them selves a "tech" doesn't mean you should listen to them.

The plugs will probably be ok but they wont perform as well as NKGs.

I've always found the best deal for NKGs on eBay.

maximatech12

...and a lot of guys and girls that are scrolling this thread probably saying who ever had backfire probably gapped the plugs incorrectly.

I would assume the gap has to be dead on at .044. I wouldn't use them right out of the box but fine tune the gapping before installation...

had a gapping gauge and even though the parts guy said they were pre-gapped I checked them. I really had to re-gap they were a bit out at .046 instead of .044...

maximatech12

Now the auto parts guy said .044 and now I realize it gaps at .043... I have to remove all of them and re-gap...

MadMax SE

I've never had to regap a ngk in my life, and the misses and detonation from other plugs are probably from the fact that they don't transfer heat as well as an ngk from the cylinder. There is a reason Nissan chose ngk over others.

MadMax SE

I had a guy at AutoZone tell me that I 100% needed 7 qts of ATF for my old 5speed dodge avenger....ofcoarse I knew I needed gear oil but I brought all that oil to the counter for ha-ha's. They hire anyone.

maximatech12

Can anyone please help? Should I ignore the parts guy and use .043 as recommended by Nissan Engineers or .044 as recommended by Motorcraft/auto parts guy?

HerBlue2kSE

In modern cars, I always install what came in it from the factory. That includes my 2000 SE that I have owned for 16 years without a bit of problems. Other engines that I have owned that are "coil on plug" have been picky about the plugs installed (Chrysler 4.7/4.7HO is a great example)

You got bigger problems than plugs if you have gas in the oil. Gas in the oil will cause it to thin out and will ruin bearings and rings. Have you confirmed that it is indeed gas?

If it is gas in the oil, I would offer that it is caused by poor spray pattern from injectors (caused by dirty injectors) or low fuel pressure (plugged filter or weak pump). I'd suspect it would also be down on power. Either way, this would be fuel getting into/past the rings. Not a good thing.

Derrick2k2SE

iTrader: (3)

It doesn't matter. The gap will open over time any way. The plugs that come out will most likely be over .060 if you check them.

You're more likely to damage the plug chasing that last thousandth than you are to see any benefit.

If you haven't installed these yet I'd return them for the NGKs.

maximatech12

They're Nickel Plated. The Maxima runs at over 208degrees F what does BMW run at/ Motorcraft Ford cars run at?
If temp plays a role

MadMax SE

You would get a better answer from google because I don't know that and neither would most people. Actual cylinder temp plays way more of a role than engine temp.