First off, I've read as many threads about this issue I can find and I'm still at a loss here, so any advice is appreciated. Anyway, here is the situation:

2002 Maxima w/59k miles
No CEL

I've noticed in the past 4-5 months that my car pings (sometimes pretty badly) only after it has been at operating temperature for a while (20+ minutes) and then only if it is allowed to heat soak a bit by driving through an urban area or idling for a bit. Mind you, it's been 20-30F lately (which makes it a little bit more difficult for me to reproduce on demand). It doesn't get hot enough that the temp gauge shows any noticable difference or hot enough to set the radiator fans off. I'll note that once I get going again, such that I'm cruising without traffic lights in my way, the pinging doesn't go away. So, it seems to be set off by heat buildup, but not easily dissipated. When it pings, it seems to do it mostly during light to medium throttle application near 2k RPM.

Now, I've read that possible sources that haven't already been addressed include the MAF, O2, and knock sensors. Honestly, I think the cold air I've been driving in rules out the MAF and I don't see the O2 sensors being exposed to temperatures it doesn't see fairly soon after the engine has been started. The knock sensor requires a multimeter to check, which I'm working on getting a hold of.

So far, I've done the following (in order)
1) Always use 93 octane,
2) Replaced the spark plugs @55k,
3) Had the rear valve cover replaced after it was found to have been leaking oil into the center spark plug well and had coolant flushed (1 bottle of Water Wetter added)
4) Added a catch can on the PCV line,
5) Replaced the ignition coils, cleaned up the spark plug that had oil leaking on it, inspected each spark plug (they all look good, just as the originals did), inspected the intake valves (very clean, I've been using 1 bottle of Redline SI-1 every 3k miles, plus lately I've been adding a bit to every tank)

Now that I think about it, it really became an issue soon after I replaced the spark plugs as part of general maintenance. Is is likely, or even possible, that the new plugs are running hotter and thus heating up the built up carbon deposits? I'm almost resigned to putting in colder plugs at this point, but would rather not lose the fuel economy b/c it's not that great in the 1st place, about 21mpg mixed city/highway (this seems to be inline with what I've been getting since it was new).

Anyway, that's pretty much everything I have. I'm hoping a knowledgable individual here can point me in a direction that I haven't thought of yet.

Thanks, Matt

 

Do anything with the fuel system (filter, injectors, etc.) to make sure you're not running lean? No light? No code?

 

Well, I run a bottle of Redline SI-1 fuel system cleaner every 3k miles and have been adding a little bit to every tank in the past 2 weeks. The fuel filter is listed as a non-servicable part as it is not easily replaced and so I haven't touched that.

There is currently no CEL or any codes stored and not reported.

The spark plugs don't appear to show any signs of running lean, but I can take a picture of one and post it if that helps.

 

I've seen few people on here saying - cleaning the Throttle body can fix the problem...

BTW, i'm having that knocking issue as well and my first step... will be changing the PCV valve...

Good luck

 

timing chain clatter

/thread

 

i'm going to agree with this one for now (btw, there's a tsb..tensioner, etc)

 

The PCV valve was replaced when the valve cover was replaced under warranty and I've since added a catch can that seems to be catching a decent amount of oil mix, so I'm not sure I can do anyting more there. Would adding a filter on the line from the airbox to the front valve cover make any real difference?

As for the throttle body, can anyone explain how a dirty TB would cause pinging? I know I'm missing something there. The upper intake manifold does have a good amount of carbon built up so maybe it would be worth while to investigate. My only concern at this point is that there has been some mention that cleaning the TB could damage it or require the ECU to be reprogramed. I'm not sure how valid those statements were, but it is something to think about.

I suppose this is possible. I must be honest in saying that I'm not sure I know how to discern the sounds one would make over the other. Is there anyway to really test for this? I get a rattle on startup every once and while that I believe is related to the timing chain and my pinging doesn't sound like that. Is it supposed to?

Thanks guys for the help.

 

while driving, does it happen around 2k rpm? if so it could be the timing chain.
http://maxima.theowensfamily.com/tsb/NTB03-060.pdf

 

any experienced mechanic can tell you it's a type of chain clatter as opposed to pinging just by listening to it. in this case, it's the timing chain. the problem is aggravated by oil consumption, but will still occur even with a full crankcase. soonerfan has been in the middle of an ordeal with nissan to fix the problem. i personally don't have the patience to deal with nissan, so i'm just going to live with it.

 

UPDATE: We had some really cold whether around here lately and the problem pretty much went away during that period. However, now that it is a little bit warmer, high 30's, it's coming back. The fact that the problem is so dependent rules out things like the timing chan IMO. Is there anyone here that is an expert with this kind of thing that can point me in the right direction?

 

Not sure about the issue your having however, the fuel filter change is quite easy. Regardless of what Nissan says. I did a write up on it awhile back, it's stickied now so you should check it out.

 

same issue...my dealer replaced my long engine block...still had problem

going lemon law route..I'll let u know how it goes

 

I would attribute this to thickening of oil during the colder temperatures...

 

1.The purpose of multiweight oil is that it has the same viscosity at all temperature ranges.

2. If what you say is true than his ping would always be occurring when the engine reaches operating temperature regardless of air temperature. He specifcally said that the problem when away during cold weather.

The only thing I can suggested is the intake air temperature sensor or the coolant temperature sensor. Both affect injector open duration and the air/fuel ratio.

 

The thing is, the car being at operating temperature is not enough, it needs to heat soak a bit, eg I get gas and when I leave it becomes very noticable or I sit through traffic and when I get out of it it becomes noticable. Thats whay the extreme cold we had in the northeast made it seem like it went away, it just makes it harder to heat soak that little bit that sends it over the edge. My opinion has been that some peripheral component is being overly temperature sensitive. I thought it was the ignition coils, but it turns out they didn't change anything. I don't know whether its a wire or whatever at this point. It's obviously very difficult to test b/c of the dependence on temperature. I guess the question is, what components are capable of causing this problem given only a slight bit of heat soak. I mean, it's warmer, but it's 32F out, so its not like it's THAT warm.

Anyway, thanks for the reponses, the discussion helps.

 

Do you have an oil catch can?

 

You are incorrect, the noise we are experiencing is indeed spark knock or "ping" as it is so often referred to. Timing chain clatter is much more consistent and is not so temperature dependent like this pinging is. Most all 5.5 gens have experienced this pinging issue at some point or another.

Like Y2Kdriver, I have done almost everything he has, short of replacing the coils. I have also done a throttle body cleaning and I still get this knock at ~2k rpm with ~20% throttle. Again this only occurs after the engine has had some heat soak, and generally 30 min or more of city driving. I must say that my hotshot headers have improved the situation slightly, perhaps due to lower egt's but it has by no means eliminated the problem.

Lately since the temps have been consistently in the < 50 deg F, I haven't noticed it much at all. I was really getting this when the temps here in GA were 80+ deg. After much thought I truly think that Nissan engineers when programming the ecu spark mapping, overly advanced it in this range to increase efficiency. It was most likely never thouroughly sorted out/tested when coupled with higher intake/engine temps and part throttle input.

The only way we could completely eliminate this would be to run a 1 step colder plug and see if that cured it, and as a last ditch effort we could get a Nissan Tech to run the Consult II and reduce the base timing to around ~12deg btdc. These two would almost totally cure this pinging, but mileage and performance would likely suffer. Not worth it in my opinion especially considering how little it effects the overall driving experience.

All things considered I think my next car with be manf. by Honda or Toyota.

 

So if you're driving down the highway for 2 hours, the problem is not as noticeable as when city driving?

After your heat soak, is the noise the same no matter how much you drive at highway speeds afterwards?

Have you tested the intake temperature sensor?

If not a sensor problem, there could be a component of the fuel delivery system that is restricting flow when hot. The thing that points to something completely different is that you are not triggering the knock sensor.

I'm surprised that the dealer can't monitor the exhaust sensors for a lean/rich condition, timing parameters, and injector operation to see any changes after a heat soak.

 

Unfortunatly, the wind noise makes it near impossile to hear well enough to know whether it is doing it on the highway or not. That being said, when I get off the highway, assuming it didn't start doing it before I got on the highway, then it won't be doing it afterwards. But if it starts doing it during city driving, and then I get on an open road with no traffic for 20 minutes or so @ <30F, it doesn't go away.

I'm not on the highway that much, so I can't say.

My thought has been that with an air temperature of <30F, that only a few minutes of driving is required before it is at its steady state temperature in those conditions. The fact that the sensor resides in a plastic tube also means that the surrounding material is not a heat sink.

It's something to consider, I just don't know.

The dealers don't want to be bothered with a complex diagnosis. They just want me to purchase whatever cheap services they offer, like fuel system cleaner, etc. Like I said in a previous post, I don't know whether carbon build up is the problem or not, but I run Redline SI-1 fuel cleaner every 3k miles and when I replaced the ignition coild, the intake valves were pristine, so who knows.

 

So myself and many others who have timing chain clatter and NOT knocking/pinging are totally wrong? I find it funny that our problems both occur at 2K rpm. Until you get an official diagnosis from a stealer or a nissan repair shop, your speculation is null.

 

My problem is not exlusive to 20% throttle application or 2k RPM. It certainly happens more in that range than others, but it's not limited to it.

 

What brand of fuel do you use?

What type/brand of plugs did you put in?

 

I use 93 octane gas from whatever name brand station is near by.

The spark plugs were replaced with NGK platinums, same as what the car came with.

 

Maybe try a catch can

 

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. . . .

 

Have you noticed if the catch can helped? For me, it eliminated about 90% of the pinging.


It sounds nothing like the timing chain rattle, which I do get in the morning when the engine is cold.

 

That is true, but the sensor changes resistance based on temperature. Perhaps it's not operating properly.

Most of the things I mentioned can be checked with a Consult-II or even a Generic Scan Tool. Take it to another shop maybe?

 

At least there is someone^^^ here that can tell the difference between timing chain rattle and a engine ping, Thank You 2002 Maxima SE!

The ping that these 5.5 gens get is so specific to the heat soak, rpm range, ambient temps and most important of all is throttle position and engine load. What I am trying to say is, if all conditions are present for this pinging and it begins to ping, all you need to do is give it slightly more throttle and It Will stop pinging.

Trust me, I have done the oil catch can, installed new NGK plugs, cleaned the throttle body, installed headers, had the timing returned to stock and I still get this ping in the warmer months. This usually happens on my way home from work in the evening and to make things even more interesting, this usually happens most when almost coasting down a hill. All I do is ignore it or just press the gas pedal down a little more and its all goes away.

 

I've been dealing with the speculation of what this is and isn't for a few years now. My belief is, based on the catch-can semi-fix, is that oil is entering combustion via the PCV...lowering octane and causing the ping. PCV flow is greatest at lower RPM. Even with the catch-can, I still get oil going by. It only takes a few drops to lower it. I've seen the inside of my upper intake manifold, there are pools of oil there.

The definitive test would be to not allow the PCV to return to the intake and see what happens on a fully cleaned upper intake manifold. However, I don't know what the effect would be of removing that vacuum from the system.

 

55k-60k
5W-30 Mobil 1

This is what comes out of the PCV in 5k miles:

 

Thats about the exact amount I see as well, 3-4 oz. or so, btw it does make for a nice sample for blackstone.

I would agree somewhat with your earlier statement regarding the fact that some oil is still entering the IM even with the catch can in place. My catch can is a Craftsmen style with a plastic/corklike filter that resides inside the lower bowl and I feel it may do a better job then some of the other pcv cans out there, as this additional element forces the oil out of the air. It does have a slight bit of a whistle underhood and the air is moving rather fast at idle, but I have gotten used to that.

 

this is way out in left field, but do you have an injen intake ? i cant explain it, but my 4th gen would ping while i had that intake installed. later i went back to frankcencar and no pinging ? no idea

 

My car is fully stock...except for the catch-can.

 

I don't have any engine mods either.

 

Anybody investigate variable valve timing as a cause?

 

I haven't even thought about that as a cause. Most of wat I've read to date has focused on the usual suspects; coils, MAF, O2, carbon buildup, etc. How would one go about investigating VVT as a cause?

 

VVT should not be open at those rpms.

 

If it is by error, the valve open duration is longer and if the injector open duration is not, that could create a lean condition.

Hell, I really don't know. I'm just trying to think of anything that might cause pinging.

 

The injen places the filter in a high temp area, therefore increasing the IAT's.

VVT doesn't 'open' @ certain RPM's