Engine Rattle in ’05 Nissan Murano

[Stephanie]

I have been looking everywhere for help on diagnosing this problem, and I have not found anything that can help me because the possible solutions have already been ruled out (ie: heat shield and gas octane) – I am hoping someone here can help me out.

I own an 05 SE Murano, currently has 80k miles on it, and for the most part it is running great – if you do not count the rattling noise it is making when I accelerate. I am going to try to be as specific as possible when describing the problem and the things that we have already checked out on it.

We bought it used from a dealership in October (’13) and starting having this problem in November (’13) and have taken it to several mechanics who can hear “something” but are not sure it is a rattle, or they hear nothing at all. The Murano rattles upon acceleration, but the rattle does not happen all the time. When it does happen, it seems to be around 20mph and between 1500 – 2000 rpm. The noise level is also different, sometimes it is a softer rattle that is on the quieter side, while other times it is more harsh and rather loud.
So far, in an effort to recreate this noise for mechanics and other engine-savvy people we have tried accelerating when the car is in park and the does not make the noise. We have tried using the emergency brake in conjunction with the normal brake, putting the car in gear and then accelerating – it does not make the noise then either. The only time we have been able to get the rattle is when the car is actually moving while accelerating from a stop. Of course, each time I have had a mechanic in the car, it does not rattle. Just today I took it out onto some back roads in an effort to record the noise on my phone and found out that I can get the rattle noise to happen more consistently when the Murano is in first gear (I placed it in 1st manually).
I have had the heat shields checked and were told they are fine. I have tried changing to a higher octane fuel and the rattle is still there. The oil and other fluids were also checked and I was told they are at good levels and that the oil had a good color to it. There are no engine lights on, and it has not thrown any codes.

I took the car out onto a back road away from traffic and made an attempt to record the noise. I uploaded the video here: http://youtu.be/nl_e0-DZuBE While watching it, the noise will start at about the 1500 rpm mark and is heard best at the beginning and the end of the clip.

Please can someone help me figure this out? I have been told by others to just let it go until I get a light, a code, or until something breaks but I do not want to do that – why not fix it now?

Thank you so much in advance, I really appreciate it. This has been very, very frustrating.

Jade

Topic

[Lorrin Barth]

You could go to the dealer and ask if they would print out any Factory Service Bulletins. In the past I’ve had them at least allow me to look on their computer. Failing that you can subscribe to one of the data services. Alldata is $19.95 for a years subscription.

http://www.ALLDATAdiy.com

[Stephanie]

We have yet to find the cause of the noise that I we are hearing in the engine, but today we finally got a place to start and I am cursing the limited number of Nissan mechanics near by as I really do not want to take the car to the local Nissan dealership.
I took the Murano to Commercial Tire today upon the recommendation of someone I talked to at the muffler shop. I figured I have been everywhere else, why not. I was pleasantly surprised to see that they actually hooked the car up to a computer and really tried to see if they could locate the source of my problem. While they did not have the Nissan tools and such required to actually diagnose the car, they did give me some avenues to explore.
The mechanic I spoke with said that it sounded like a detonation noise and suspects that it is releasing too much fuel (which could explain why the mpg sucks). He could not confirm this because he does not have the required Nissan stuff to do this with, but he felt confident that was the problem. He said that it was not the timing chain as the noise was not consistent, and it did not have the right sound. He also suggested looking at the spark plugs and mentioned carbon build up as well.
Another search online suggested retarding the engine base timing retarded by 2 degrees because “the ECU is “optimized” in Nissan products to advance the ignition to the very point of pre-ignition in an effort to maximize fuel economy. What happens is that when the vehicle starts to accelerate, the ECU will advance ignition timing as soon as possible, plus the torque converter is locked at the earliest opportunity and as a final trick, the CVT will “shift” to higher gear as soon as possible. Again, this is all done in order to achieve maximum fuel economy. The problem seems to be that Nissan’s ECU is too “aggressive”. It advances ignition so far, that knocking (pinging) occurs, at which point the knock sensor is activated and the ignition is then retarded to avoid further knocking.” Others have posted on the thread I quoted from as saying that Nissan believes the noise is normal which I think is bs because it was not making this noise when we bought it, it started a month later – but that’s just my opinion.

I have not seen any service bulletins for this problem, and before I even asked today’s mechanic about them he said that he did not see any as he was looking into buying a Murano himself. Anyway, I go to see yet another guy on Friday who works on imports who agreed to take a look at the Murano. If we get nothing there, then I will be driving about 1.5 to 2 hours out of town to a Nissan dealership and hope I do not have a heart attack over the cost.

So, my list of things to look at:
– Spark plugs
– Clean possible carbon build up
– Check sensors
– retard engine timing 2 degrees (not sure on this one though)

I’ll update, yet again lol, when I get more information or if I even manage to get the problem fixed. Thanks for all the replies and ideas!

[Lorrin Barth]

“I have not seen any service bulletins for this problem, and before I even asked today’s mechanic about them he said that he did not see any as he was looking into buying a Murano himself.”

Since you are not sure of the cause it still may be worth checking.

There’s many for my automobile and my car is nearly trouble free. There’s one that says you may experience buffeting if you roll down the rear windows at speed and that this is normal. There’s one that is a revised procedure for installing the sun roof – now called a moon roof. Coming next – a Mars roof.

Some are silly but some are important.

[Stephanie]

I should have been more specific, I have not seen any service bulletins that relate to the problem that I am having. I thought I had found one that could help, but it was about the fuel level. I found about 11 pages of bulletins though so I know my Murano isn’t perfect – although I wish it were lol.

[Lorrin Barth]

Sorry, my reading comprehension is on low tonight. However, since you’ve seen the TSB’s keep them in mind. They are a list a common problems with the vehicle. So, these are things you can watch for. Very handy.

If the problem is what you are thinking, you might try a fillup with the highest octane you can find just to see what that does.

[Stephanie]

No worries, I have my own moments as well so it’s all good. 😉

We are on a half-tank of mid-grade fuel at the moment and when it comes time to fill it up we’ll most likely bite the bullet and fill it with the highest octane we can find and see what happens with the noise. To be honest though, I am skeptical if it will help as we have used octane booster on the low and medium grades and we still have the noise. We did low grade with boost, mid-grade, and the current tank is mid-grade with boost and the noise is still there. Would it make sense to add a boost to the highest octane as well or would it be redundant?

[Lorrin Barth]

I have two cars and they both require premium fuel. I endure the pain.

I’ve never used octane booster but the story I get from the guys with modified engines needing high octane, and they will use anything that works, is that the octane change obtained by adding a bottle of octane booster to a tank is so small it is essentially worthless.

[Stephanie]

So yet another trip to a mechanic, this time to one that works on imports and had the diagnostic tools necessary to read my car’s computer. Electronically, everything checks out; no codes or issues there and the mechanic also does not believe it is a timing chain issue. My car cooperated and made the noise for mechanic to hear who believes it is a pre-detonation sound. Rather than racking up a huge bill tearing things apart and replacing parts that may not need to be replaced, they are starting me back at the beginning and working from there so the current plan is:

Cleaning out carbon build up by taking a “road trip” and running it up the steep grade that leads out of town. I also put a carbon cleaner additive into the gas tank as it was 3/4 full.
Changing the fuel to a non-ethanol premium and see if that changes or eliminates the noise. They said I could put in an octane booster to the current tank (as it’s almost full) to see if it helped, but I figure it would be better to clean some of the build up out first before boosting the octane – if it’s dirty a boost isn’t going to help I don’t think.
If the noise goes away, then great we solved the problem, if not, then we have other avenues to look at – what those avenues are I don’t know yet lol.

We are still tossing around the idea of changing the spark plugs as well. I know that it is recommended to change them at 100k miles; the Murano is just shy of 81k so would it be a good idea to change them out now?

[Bill]

Octane booster is only more “snake oil”

[EricTheCarGuy]

Actually that doesn’t sound like a bad plan. Keep us updated on how things go.

[Stephanie]

Quick question or two…

After putting the cleaner additive into the gas tank and running it from 3/4 full to 1/2 full I have noticed that the rattle/ping/detonation/whatever-you-want-to-call-it has reduced some. It is still there but it is not as frequent as it used to be. Considering that I am an impatient person I have some questions about cleaning the carbon even more. I went to google and found this “article” about using SeaFoam to clean the engine. Here is a link to the article: http://www.nicoclub.com/archives/how-to-use-seafoam-to-clean-your-engine-the-right-way.html

My questions are: Should I consider doing what is suggested in the article? As I have already put cleaning additive (that is NOT SeaFoam) into the gas tank, would doing something like this hurt the engine? Should I just leave things well enough alone for now and just go with the higher octane fuel when it is time to fill it up?

Also, should I change the plugs once I have cleaned the carbon out of the engine, or should I wait until it is closer to the 100k mile mark?

[Stephanie]

Yep, I’m back…

Changing the fuel octane and going non-ethanol did not stop the engine noise so we decided to SeaFoam the engine. MASSIVE amounts of white smoke (thankfully we did this when the neighbors were asleep). When taking the car out to drive to clean it out afterwards, there was the rattle/noise when accelerating after pulling out of the driveway but my husband said that he did not hear anything afterwards (but I cannot say that he was actually paying attention to the noise rather than the amount of smoke coming out of it).
Tomorrow we are going to replace the spark plugs and I read on various other forums that using colder spark plugs will help with the pre-detonation issue. When reading a “walk-though” on how to change the plugs on the Murano it suggested using NGK PLFR5A-11 spark plugs. I am going with the assumption that these are factory temperature rated and not colder plugs. How do I tell that a spark plug is rated as colder? I also read that using colder plugs is mostly for engines that have been modified and/or are using nitrous, is this true? Should I even bother using colder plugs? What would you guys do if you were in my shoes?

[college man]

The stock plugs are set up for a stock engine and will
deliver the best performance. Use the recommended NGK plugs.

[Stephanie]

Updating real quick because I think we have the issue taken care of – which makes me super happy. I have not heard a rattle from the car since we SeaFoamed it and we drove it pretty hard (within speed limits and such)and it is running great. It also looks as though the mpg is picking up as well which is another huge plus.
I just want to thank everyone who replied and gave me their comments and advice. It was a huge help to me and I really learned a lot about my car. I really appreciate the time you gave me, you have no idea.

THANKS!

[EricTheCarGuy]

So I guess we can chalk this one up as ‘carbon buildup’ inside the engine causing the detonation. Interesting. Thanks for the updates and for using the ETCG forum.

Keep us posted if it comes back.

[Author]

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