jgcable

I got a call from the mechanic today. When he first started the car it smoked and hesitated like crazy. Yesterday he started it and it ran great with no smoke at all. Today he went through the motor checking the plugs, the PCV valve and the MAF sensor and all the other sensors. Everything checks out perfect and the car has been running perfect all day. He can't find a single thing wrong with it. He told me that since it has 160K on it maybe the engine is at the end of its life but that wouldn't make sense because the motor runs perfectly. He did say that when it was smoking it was definately oil smoke and not unburned fuel smoke. That would usually point to internal engine problems but that doesn't explain why the car did the exact same thing 1 month ago, it suddenly cleared itself up and ran great for the last 4 weeks, it acted up again 5 days ago and it has been running great since. Basically.. he has no idea what is wrong with it. Neither did the other repair shop I brought it to. He told me to pick up the car tomorrow and drive it and when it acts up again to bring it to him immediately. There has to be a logical explaination for why this is happening.

So the question is... to all the Maxima Guru's here... what would cause a perfectly running engine to suddenly start belching oil smoke out of the tailpipe and running rough and then suddenly clear itself up only to act up again. The computer is showing no codes of any kind. The oil is perfectly clean.

The Wizard

iTrader: (43)

Sounds like the mechanic checked the MAF etc when your car was having a good day. He should have checked everything the day before when it was acting up. Bringing it back when it acts up again sounds stupid. I'd get a 3rd opinion.

jgcable

The mechanic suggested me to bring the car back when it acts up again. Is there anyway for me to test the maf

The Wizard

iTrader: (43)

I don't think you're getting my point. Any way, a MAF can be tested with a multimeter. Have you looked in the FSM? (see sig) I would jiggle the wires too to see if you have an intermittent connection.

Also, see this:
http://easyautodiagnostics.com/nissa...e-maf-sensor-2

jgcable

I asked him specifically about the MAF and he told me that a faulty MAF would not cause the motor to start spewing clouds of oil smoke out of the tailpipe. Is this true?

jgcable

When I get the car home tonight I am going to check the MAF.


Let me ask this...
Suppose the car is running fine and all of a sudden it starts hesitating and smoking like crazy. Is there anything I can do to check to see if its a faulty MAF under those conditions?

dwapenyi

iTrader: (3)

You've done the FPR. Good. You must have a bad ignition coil......and it only goes bad when the car is warm. When the car idling and your put your hand on the tailpipe to feel the exhaust coming out, is it a puff puff kind of feeling? Definitely one of the coils then.

jgcable

It doesn't only go bad when the car is warm.


1st time it happened. 1 month ago. Car was only driven 2 blocks. It started perfect, idled perfect and 2 blocks later it was hesitating and blowing whitish blue oil smoke out of the tailpipe. ALOT of it. Took it to a repair shop.. they couldn't find anything wrong other than a dead battery. They checked the injectors, the fuel pressure, a leak down test and the ran a scanner over the O2 sensors and everything checked out fine. It did throw a code at that time. I believe he told me it was P0300 or something like that. It was a cylinder misfire. The next day when the battery was replaced the code was gone. He told me he couldn't tell me why the car did what it did but to come and pick it up because its running fine. The car ran great with no issues for an entire month.


2nd time it happened was 5 days ago. Keep in mind.. this is a daily driver that is driven to work and to college and back every day. Took the car to school which is 15 miles away. Ran perfect. When my daughter got out of school and started the car up she noticed that it started rough. As she attempted to drive home the car got worse and worse with smoke pouring out of the tailpipe and it eventually stalled at a light and wouldn't restart and had to be towed.


We had it towed to my house.


I replaced the FPR, I checked and cleaned the plugs. Everything seemed fine. I put it back together and it started right up and idled and ran perfect. I really thought I fixed it!! I took it for a ride around the block and within 2 blocks it started hesitating and smoking like a ***** out of the tailpipe. I barely made it back to my driveway. That's when I threw up the white flag!!


I had it towed to another repair shop who is regarded as one of the best in town. The first time he started it, it ran like crap and was blowing a lot of whitish oil smoke out of the tailpipe. He didn't have time to work on it so he told me he would tear into it the next day.
The next day he started it up and it started perfectly with no issues and no smoke. He checked the plugs, the MAF, the PCV valve. The car is throwing no codes. He ran it on an off all day and couldn't get the car to run bad. He told me it is running perfectly and there is nothing he can do until it acts up again. We are going to pick the car up today and I am going to drive it from now on because I can't take the chance of my 20 year old daughter getting stuck in the car to and from work and school.


This leaves me in a real pickle because I need the car to be dependable and so far.. 2 very reputable repair shops can't find anything wrong with it. I guess I am stuck with driving it until it leaves me stranded and having it towed back to the repair shop. Just doesn't seem to me like something like this hasn't happened before. There are thousands of Maxima's on the road. Most of them are beat to hell and still run great. Mine is maintained like a jewel and it is really turning into a lemon that I might have to sell. I can't have a car that randomly has issues this severe.


I have always turned to forums for stuff like this because it usually turns that I will find an answer here.

dwapenyi

iTrader: (3)

Replace your valve cover gaskets...which include the the spark plug grommets (gaskets). My guess is that one of those gaskets is leaking so bad that oil is dumping into one of the combustion chamber of one of the cylinders. The leak is so bad that it's causing a misfire.

Valve covers gasket replacement is a common maintenance item. No biggie really.

jgcable

And to answer your question directly...


It doesn't go bad when the car is warm. The 3 times that it has happened the car was cold and only driven a few block.


Then the car is running good the exhaust is smooth. The engine is perfectly smooth with not a hint of hesitation. No noise.. no issues. It runs like a brand new motor. When it mysteriously acts up it hesitates, it has a rough idle and it billows whitish blue smoke out of the tailpipe. The mechanic told me its oil smoke which would usually point to internal engine problems (rings etc...) but it can't be because its RANDOM.


The best way to describe it old school is...
Back in the 70's when cars had carburetors and you had a carb that had a bad choke and a stuck float the car would run rough and belch smoke out of the tailpipe. This is pretty much exactly what my Maxima is doing.

jgcable

He said 2 of the plugs had a little oil residue on them but nothing that would cause smoke or a misfire.


A month later when it happened again I removed the plugs and there was no oil on them or the tubes. They were very dark though which would tell me that the motor was running rich. They weren't wet, they weren't covered in oil.


Would I see oil when I removed the spark plugs? The reason I am asking is when I removed the plugs on Saturday they didn't have any oil on them. There was no oil in the spark plug tubes either. If the motor was leaking oil that bad into the combustion chamber of one of the cylinders I absolutely would have been able to see it on a spark plug. That happened to me once on a Plymouth Neon. It ended up being one of the Spark Plug tube O-rings. It was easy to tell which one because the spark plug was COVERED in oil. It even started seeping up into the tube.
On my Maxima the tubes and the plugs had NO oil on them at all.

dwapenyi

iTrader: (3)

My thinking is that the spark plug oil observation is a sign as well as your sudden oil in tailpipe observations. The oil may not be necessarily leaking into the combustion chamber from the plugs. The VC gaskets cover the whole top of the engine that is bathing in oil. The engine is a 24 valve V6. So there are many places up top from which the oil can potentially leak into the combustion chamber.

Just a hunch If it's wrong, this is still a maintenance item you are eventually going to need to do anyway, like in the next 40K miles or so.

dwapenyi

iTrader: (3)

If Tracy Morgan hasn't made it clear, umm, no.

Keep maintaining it the way you have, you can easily see another 250K miles out of your engine. The VQ30DE engine in your car ain't the most powerfull anymore, but the newer VQs can't touch their longevity.

jgcable

Picked it up an hour ago from the mechanic. Its running perfect. Smooth idle, no smoke, no issues of any kind.


Now its a waiting game to see when it happens again.
This sucks.

asand1

iTrader: (1)

LoL, you are just getting broken in with 160K, I currently have over 300K miles on mine with no signs of impending doom, and there are people here with more.


And this is more evidence that your pintle caps are coming apart. Raw, un-atomized fuel is pouring into your cylinder(s) creating a cloud of unburned (not black over rich burned) fuel. As it gets worse the intermittent aspect will disappear and you will constantly run like ****. Eventually you will leak so much you will hydrolock on fuel, possibly bending a rod.

Buy some intake gaskets, and the pintle cap kit and get it done now. You won't really know if they're bad until you expose them, and until you rule them out you might just be chasing a red Herring.

Fakie J Farkerton

iTrader: (51)

Anyone say pintle caps yet?

jgcable

I know.. I know.. but...
How do you explain the fact that the car ran perfect all day yesterday and so far its running perfect today? How do you explain that the car did the exact same thing a month ago and magically cleared itself up for over 1000 miles of flawless driving only to act up again and now it cleared itself up again all by itself and is running perfect. If the injectors were bad or if it had broken or cracked pintle caps it would run bad all the time right?

jgcable

I hear what you are saying but it still doesn't make sense. if the pintle caps are coming apart than how can the car go from hesitating and crop dusting smoke out of the tailpipe to running perfect a day later? They don't magically repair themselves. Its totally random as to when the car is going to act up. It has done it 3 times in the last 6 years. Once a month ago. Once 5 days ago and once 3 days ago. It has been running perfect since yesterday and no repair work has been done. From what I read about bad pintle caps the car would be hard to start, smoking and generally running like crap. My motor is running perfectly for the last 2 days. WTF???

CMax03

iTrader: (3)

Hard Head = empty lightweight wallet!

jgcable

So this is what I am going to do since I have just been called a hard head.


I am going to drive the car until it acts up again. When it does... instead of taking it to the repair shop I will limp it home hopefully and I will tear off the intake manifold and pull all the fuel injectors and check them out. I can't pinpoint which one is bad because all my plugs look the same. None of them are wet with unburned fuel.
If Its not the pintle caps you pintle cap witchhunters are going to get an earful! Just kidding... thanks for all the help so far!


Still... nobody has come up with a valid reason on how a broken pintle cap or caps can repair themselves for up to a month or render the car undriveable one day and then the car runs perfect the next day!!!!!
I would love to hear the reason behind that.

The Wizard

iTrader: (43)

I still think it's
a) injectors
b) pintle caps
c) faulty injector wiring
d) any combination of above

No need to wait until it acts up again. You won't be able to tell a bad fuel injector just by looking at it, only bad pintle caps.

It's unlikely, but I'd start by jiggling the injector wires (and MAF wires) and see if the cars behavior changes and the bad intermittent behavior returns. If no luck there, then I'd probably send out the injectors for testing, cleaning and a full rebuild (which will include new pintle caps). I think one or more injectors is sticking and/or leaking due to bad pintle caps. At their age, they're due anyway IMO.

dwapenyi

iTrader: (3)

Everybody else says injectors. I say, before you do that, replace the valve cover gaskets. It's cheaper too.

jgcable

To update... we picked the car up yesterday. It ran flawlessly. I took the car to work this morning and it ran flawlessly. No issues at all. No smoke, no hesitation, started instantly, extremely smooth idle.
There is no way that this can be cracked or broken pintle caps or valve cover gaskets. It HAS to be something electronic or some kind of sensor. I remember back years ago I had a Harley Davidson Sportster that would do the same thing. It ended up being a faulty intermittent engine control module. I had that bike at 2 different repair shops. They did intake work, carb work and a bunch of other things and still the bike would act up on rare occasions and get me stuck. I mentioned to them that it sounded like something electronic because it was so random and they both disagreed saying that it had something to do with the intake/carb. I bought an ECM used on Ebay for $10.00, slapped it in on a hunch and the bike has been running perfect for the last 5 years.

njmaxseltd

iTrader: (19)

I'm not buying the pintel cap idea either. The problem would be constant, not intermittent.
Definitely not the valve cover gaskets, that makes no sense either.

All the spark plugs look the same, it's got to be an a/f issue or PCV?

jgcable

The first thing both mechanics and I checked were the plugs and the PCV valve. All the plugs except for 1 were very dark but not covered in oil or smelling of fuel. 2 of them had a VERY small damp spot on them. It looked like fuel residue, nothing that looked unusual to me or the mechanics that looked at them. To me they looked like plugs that came out of an engine that is driven around town mainly or running a little rich. There was one plug... the # 5 cylinder that was not nearly as dark as the others. It was a dark tan colored and looked fine.
The PCV valve was perfect and it rattled fine. I removed it and sprayed it out anyway.
Hesitation and a rough idle is something that I could attribute to fouled plugs or a clogged PCV valve or something like that. The thing that has me stumped is how this motor randomly goes from running perfect to billowing clouds of whitish blue smoke and running terrible and eventually stalling and having to be towed only to magically "repair" itself.

dwapenyi

iTrader: (3)

I guess it could be an electrical issue, but what explains the smoke and all that oil coming out the tailpipe? If an electrical issue, clean all the ground connections. Any wire attaching to the body or engine is a ground point. The simple process of unscrewing and screwing things in again is the easiest way to clean a ground connection.

While you can use the FSM (found here http://www.boredmder.com/FSMs/Nissan/Maxima/) to find all the ground points, here are some of them off the top of my head;

On the passenger fender, around the windshield washer coolant filler neck, you should find 2 wires (not quite next to each other) screwed into the fender. That's them.

On the engine timing cover, above the belts, halfway to the top there should be another one.

On or around the front valve cover (the pretty thing labelled NISSAN 3000) there should be 2 right next to each other. Maybe you have to take the valve cover off to see them. These 2 ground the fuel injection wiring.

That's all I can remember. While you're at it, you may want to add a grounding kit. You can buy one or make your own, like I did. I just bought a bunch of battery cables and added connections all over the engine bay; engine to passenger fender, engine to firewall, tranny to drivers side fender etc.

Of course it goes without saying that you should do all this work with the battery dis-connected

jgcable

I guess it could be an electrical issue, but what explains the smoke and all that oil coming out the tailpipe?


The only thing I can think of is some kind of computer issue where its sensing an extreme lean condition and dumping fuel into the motor. Either that or one of the fuel injectors is intermittent and every time it goes bad it ends up stuck open instead of stuck closed which would dump raw fuel into the motor. The weird thing is I thought it was fuel smoke but the mechanic said it was definitely oil smoke. The smoke was white. Not white like blown head gasket but definitely not blue or black. It was bluish white leaning towards the white shade and it was REALLY smoking a lot.
For the last 3 days.. (one day with the mechanic and 2 days at home) the car hasn't smoked at all and the idle is perfectly smooth. It really is a mind blower

The Wizard

iTrader: (43)

We're gonna give you the biggest "I told ya so" if it's the injectors.

Has a mechanic hooked up their scanner and read the live data when the car is acting poorly? I believe you said they only did this when the car was behaving normally.

jgcable

Yes, the first mechanic hooked it up to their scanner while it was running bad and he said it showed a P0300 multiple cylinder misfire. He shut the car off and planned on looking at it the next day. The next morning the battery was dead. He pulled it, charged it and when he reinstalled it and started it up it was running perfectly and there were no codes. At that time he did a full scan on it and everything checked out perfect. He told me that he thought it might have been a voltage problem because of a bad cell in the battery or it could be that the motor is shot and needs rings. He suggested that I change the oil and try running high mileage oil or full synth. The car ran perfect for 4 weeks after that without even a hiccup.

The next mechanic wasn't able to get the car to run bad except for the first time he started it when it was dropped off. The next day he started it and it was running perfect with no codes and no issues. He ran it around the entire day and then called me to come and get it. So far its been running perfect yesterday and all day today.

Finkle

Any chance the ECU is crapping out and randomly deciding to dump fuel when it feels like? Just throwing it out there. I skimmed the thread and thought that it might be worth a shot to look at what controls the injectors rather than the injectors themselves.

Maybe you also have a ground issue with the coils. I had a bad coil on my max, it ran a little rough, but not enough to kill the car.

It could be a number of things that only would show up when the car is running like ****. O2 sensors could be taking a dump, maf, coil grounds,

jgcable

O2 sensors were both checked and are in spec, MAF was checked, coil packs and grounds were all checked. All were perfect. Car has been running perfect since we picked it up on Thursday.
This is a complete mystery.

jgcable

2 more rides back and forth to work. Running perfect. No smoke, smooth idle.

JvG

I'm reading this thread at the same time I removed my UIM to chase down possible clogged tubes to solve an "EGR insufficient flow" problem.


My car has 190k on it, and runs quite well. The fuel injectors are accessible now. Following the old saying of "while I'm in there anyway I might as well"
I think this would be a good time to remove them and send them to an injector service shop to have them cleaned and new pintle caps installed.
I can imagine how I would feel if I reinstalled the UIM and six months from now I had the problem the original poster does.

jgcable

I agree although I don't think the problem with my car is injector related. Bottom line.. if I had the UIM off I would absolutely pull the injectors and replace them or have them serviced. No question about it.

JvG

I just recalled a very similar situation I experienced a long time ago. I had a 1973 Volvo with Bosch D-jet electronic fuel injection. It suddenly started spewing a blue-white cloud of crud out the tailpipe. It stunk of gasoline.
The problem was caused by something called an intake manifold air-pressure sensor. A diaphragm ruptured inside it. It caused the computer go to a full-rich setting that held the fuel injectors fully open. You mention that the cloud smells like gasoline, similar to a sunken float on a carburetor. We are both old enough to remember that smell. I bet your fuel mileage is terrible all of a sudden. Also that your oil consumption has NOT increased. If so, your problem is fuel injection related, NOT mechanical engine problems. I would take the car to a different mechanic for a second opinion.


I would also trust the advice of those on this forum who are trying to help you. Especially those like The Wizard, Faaki, and CS AR. They have been in your shoes, they know what they are talking about. They have solved your problem on their own cars.

JvG

Also Asand1. And Fakie Farkington.


Fuel injection problems smell like a sunken float on a carburetor. Burning oil smells like an old Chevy Vega. Bet your Max does not smell like a Vega.

dypkny

agreed

dypkny

even if you don't want to spend the money, you have to start somewhere

jgcable

At this point I don't see any reason to take the motor apart. I have been driving the car every day for the last 7 days and its been running perfect. No smoke, no hesitation, perfectly smooth idle. There is now way its pintle caps unless they magically repaired themselves.

dwapenyi

iTrader: (3)

So what was done 7 days ago?