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Discussion Starter #1
I hope someone can help with my issue.

I have a 2003 Murano and after 12,000 miles or so, I started to notice some pinging or knocking from the engine. Assuming bad gas, I started alternating between gas stations (Hess, Shell, Gate). Since owning the car, always filled with 93 octane no matter where I refilled the tank. Also, performed oil changes every 3,000 to 4,000 miles. Average driving speed 40 to 50mph with some stop and go.

Knocking was getting worse with time and only took place on acceleration.

1st. Dealer claims after two repair attempts that it was bad gas. In both instances, he reset the computer to "learning mode". On one occasion, he retarted the timing 2 degrees which seem to have helped for about a month.

Pinging returned and 1st Dealer claimed that they cannot do anything else.

Went to a 2nd Dealer who at least seem to make a better attempt at resolving the issue. On first visit, suggested carburator cleaning to clear out some carbon deposits. I was not convinced that this was the issue, nevertheless, I went with their recommendation at $90. Pinging got worse!

On my second visit today, Dealer and Nissan Tech Support report that I need the engine cleaned due to massive carbon buildup in the cylinders. I have seen the cylinders and they are black with carbon deposits inside. I was floored.

The car has just reached 19,000 miles and Nissan wants me to spend over $600 on a cleaning with possibly new spark plugs.

My biggest issue besides that this should be a warranty job is that they will clean the engine but they have not solved the problem. Am I going to get another $600 cleaning bill at my next 12,000 miles?

My suspicion is that there is something wrong with the computer or its sensors but I can't seem to convince them of the fact. There must be something wrong with the fuel-air mixture to cause this rapid buildup.

Note that we also have an '99 Accura TL that gets its gas from the same source and it does not have any issues.

Has anyone else out there experienced something similar with the Murano or does anyone have any suggestions?

Thanks.

:confused:
 

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anbreau said:
I hope someone can help with my issue.

I have a 2003 Murano and after 12,000 miles or so, I started to notice some pinging or knocking from the engine. Assuming bad gas, I started alternating between gas stations (Hess, Shell, Gate). Since owning the car, always filled with 93 octane no matter where I refilled the tank. Also, performed oil changes every 3,000 to 4,000 miles. Average driving speed 40 to 50mph with some stop and go.

Knocking was getting worse with time and only took place on acceleration.

1st. Dealer claims after two repair attempts that it was bad gas. In both instances, he reset the computer to "learning mode". On one occasion, he retarted the timing 2 degrees which seem to have helped for about a month.

Pinging returned and 1st Dealer claimed that they cannot do anything else.

Went to a 2nd Dealer who at least seem to make a better attempt at resolving the issue. On first visit, suggested carburator cleaning to clear out some carbon deposits. I was not convinced that this was the issue, nevertheless, I went with their recommendation at $90. Pinging got worse!

On my second visit today, Dealer and Nissan Tech Support report that I need the engine cleaned due to massive carbon buildup in the cylinders. I have seen the cylinders and they are black with carbon deposits inside. I was floored.

The car has just reached 19,000 miles and Nissan wants me to spend over $600 on a cleaning with possibly new spark plugs.

My biggest issue besides that this should be a warranty job is that they will clean the engine but they have not solved the problem. Am I going to get another $600 cleaning bill at my next 12,000 miles?

My suspicion is that there is something wrong with the computer or its sensors but I can't seem to convince them of the fact. There must be something wrong with the fuel-air mixture to cause this rapid buildup.

Note that we also have an '99 Accura TL that gets its gas from the same source and it does not have any issues.

Has anyone else out there experienced something similar with the Murano or does anyone have any suggestions?

Thanks.

:confused:
According to your note it sounds like you only drive in the city, I would highly recommend that you take it on the highway and allow the carbon to get blown out at highway speeds as all cars need this from time to time. You will probably notice that your fuel economy will improve to. I drive on the highway everyday and trade the Mo from wife at least once a week ( as long as I am a good boy), my trip to work is 75 Km roundtrip.

A special note to the dealership that recommends that you clean out your carburator, fuel injected cars do not have carburtors and anyone who says that they do needs to give their heads a shake.

:banghead: :banghead: :banghead:

Take your Mo on a nice highway roundtrip of at least 100 miles and see if the pinging goes away. This should clean out the carbon in the cylinders and spark plugs. Let us know what happens.:29:
 

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Discussion Starter #3
Thanks for the suggestion.

I can't believe that I missed the carburetor vs fuel injection part. Now, I am not sure what they did in the first "cleaning". I will remind Nissan on this...

The Murano is now sitting at the Dealer and I am waiting on a call back from Nissan to see if they will accept it as a warranty issue. The Dealer doubts that they will follow through which will make me very disatisfied.

The driving is about 40% city (40mph with some stop and go) and 60% highway (+60mph). Our city is very spreadout. I am familiar with the high speed drive to blowout the muck which did not help in our case.

There are at least 2 other Muranos in our neighborhood with similar driving conditions and using the same gas stations without the issue. However, I am not sure on their total mileage yet.

My wife and I are now worried about driving the car any further because the pinging has gone so bad. I may be forced to go ahead and have the cleaning done just to drive the car again and then fight Nissan if they do not come through.

Thanks again.
 

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anbreau!!!

You mentioned that the Pinging stopped when the dealer retarded the spark to -2 degrees and put it in the learning mode. It sounds like the spark timing is being mis-led by a bad knock detector that is not detecting Knock or if it is, it's not being able to get the computer to acknowledge it.

That s why it was OK for a while and then got bad again. It (the CPU) kept advancing the timing wait to hear the knock and never has.

The carbon is because the combustion is not complete and knocking can do that. You need ANOTHER PERSON TO DO YOUR ENGINE go to an infinity dealer, go somewhere but make it elsewhere. Bad knock can damage an engine Go After you talk to them on the phone, ask for the service manager and get him to listen to the situation and make a positive "I think I can Fix it" type comment before you go to them.

This needs to get fixed!!
 

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You are driving your MO to slow. You should take it for fast driving trip. You should make a lol of accelerations, and drive the fastest you can. Our engines likes high speeds and acceleration rather low speeds. For example make several hard accelerations form 30 mph to 70-80 mph or faster and then stay at that speed for few seconds. It should help.
 

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This "cleaning the engine of carbon" is an expensive fishing expedition. They have no idea what is wrong with your vehicle. There are a lot of vehicles that never leave the city and haven't developed an engine ping at 12K.

This is a warranty issue IMHO.
 

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Clearly a 40/60 city highway mix would not be the recipe for carbon buildup, so I don't buy the you need to drive your car harder argument in this case, although its true you do need to "open it up" every so often to blow the carbon away (how much difference this makes I have no idea, but the concept sounds ok).

Excess deposits in a modern car tend to be due to a computer issue rather than a fuel issue. My guess is that your computer is stuck in open loop mode due to a defective oxygen sensor or coolant temp sensor. A rich fuel mixture encourages carbon deposits.

I also like Grip's idea of a defective knock sensor. I know on older Nissans, a bad knock sensor does NOT turn on the check engine light, but it does store a code. Your dealer should be able to confirm this. If they did not check for codes, go to another dealer. Carbon cleaning on a 19,000 mile car is not acceptable and clearly the engine is not running efficiently.

If you make a lot of short trips in the city (where your coolant temp never gets to really heat up), then I can agree with the carbon deposit and not driving enough argument.
 

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Discussion Starter #8
Thank You All for the Replies!

Your answers so far have supported my theory that such levels of carbon deposits on such low mileage is not normal. Actually, both the mechanics and the service manager agree that this is an unusual situation but are "helpless" in convincing Nissan Corporate that this is a warranty issue.

It is up to me to do the convincing. A $600 bill to fix this issue is not in my budget at the moment especially that the root cause will not be corrected...

A couple of responses to your replies:

1) Did run a long distance highway trip before going back to the Dealer. The pinging was so bad, that this is what prompted us to return ASAP to the Dealer.

2) No error codes have ever been reported by the computer.

3) This is my second dealer. He is actually the one that sold us the vehicle. He at least seems to be making an effort to help. In our city, a very few powerful individuals (or families) own most of the dealerships. One actually owns the Hondas, Toyotas, Nissans, and I think the Infinities.

4) I submitted a few of your suggestions to the Service Manager indicating the sources as from very helpful Murano owners.

It is now in the hands of Nissan...I can't wait for tomorrow...
 

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Eric, I think, hit the nail on the head: it is overly rich, you should have horrible mileage. It should be detectable by smell and by any emissions testing place. If you had a slip from one of the emission testing places that had way nasty numbers, it might prompt Nissan to fix it.
Good luck!
 

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I think the Nissan dealer said carb body & really meant throttle body,
anyway I would hope they're that smart anyway. I think your problem started by using 91 octane gas & not driving the vehicle very aggressively. Octane is a measure of the resistance to preignition or detonation, which means it is actually harder to initiate combustion w/ a higher octane fuel. If you put a high octane fuel in a vehicle that does not require it, you will get a large carbon build up due to the lack of complete combustion & lower egt's.

I suggest taking it to a Nissan dealer that understands what a topend carbon cleaning is & then use lower octane gas (87 or 89 depending on the type of driving,climate,etc). Drive w/ the lowest octane gas you can while getting little to no knock. An occasional knock under heavy load is OK, but if it persists switch to the next higher octane.

My wife drive's her Mo pretty conservatively, so I take it out for shall we say an aggressive spin each week!:D
 

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Actually the Murano can use premium, as its the recommended fuel. ;)
 

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Eric L. said:
Actually the Murano can use premium, as its the recommended fuel. ;)
If you look closely at the label on the inside of the fuel filler door, it says for maximum performance premium fuel is recommended. If you're just driving at primarily low load conditions, the ECU uses little timing advance & low octane fuel will actually burn more completely. If you drive aggressively, i.e. high load % in the ECU table, it will advance the ignition until knock is detected & then & only then is premium fuel going to give you more power or maximum performance.

I have personally seen torn down low mileage engines with excessive carbon buildup on the tops of the pistons & valves due to the use of premium fuel in vehicles driven conservatively most of the time.
 

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Discussion Starter #13
I found out today from the Dealer that Nissan is refusing to honor their warranty for this issue.

3 calls to Nissan from my part as generated no action and their Warranty Specialist has yet to return my calls.

With my back to the wall, I have decided to have the engine cleaned as recommended and then proceed to file complaints straight to Nissan Executive. I may get lucky and get better response for the higher ups but I am not holding my breath.

Based on their behavior in assisting on a vehicle that is less than a year and a half old, we are contemplating on ridding ourselves of the Murano in favor of an Accura or Toyota which from our experience treat their customers better. I figure we will have about 12K miles (1 year) before the next carbon issue.

Sadly we like the vehicle but have completely lost faith in Nissan. God help us if we encounter any "complicated" issues with the engine or transmission!

I realize that no other cars out there are perfect but I do not recall ever getting such bad customer service from a company.

Thank you all again and take care.
 

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Oh! "A a 2003 Murano and 12,000 miles. You have a case a lemon, what is the excuse for not honoring the warranty. You have an implicit fittnes of use claim.

What is thier stated reason for not fixing the engin, exactly what is thie statd reason.

This really makes me, sad, disappointed and mad all at once. How can I help, give me an adddres a phone number, something. I want to take action. Can you in a numbered list tell us what has happened.

First visits, problem statement, reaction etc. This is terrible. terrible terrible, Damn. :3:
 

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"I have seen the cylinders and they are black with carbon deposits inside. I was floored."

How was this accomplished?
How did you "see" the cylinders?

Homer
 

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What I fear in your case is that the same problem will cause the engine to get all carboned up again in another 20,000 miles. The dealership must find the cause of the problem, not just treat the symptoms!

If all else fails, perhaps you could take it to an independent Nissan specialist. Not a dealer, but an independent mechanic who specializes in Japanese cars (maybe even a place that does modifications to the import racers). Those shops tend to understand engine electronics very well and might be able to fix your problem if the dealer is too incompetent to do so.
 

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hfelknor said:
"I have seen the cylinders and they are black with carbon deposits inside. I was floored."

How was this accomplished?
How did you "see" the cylinders?

Homer
I don't know if you are referring to my post. But I said the engines
were torn down. I have also inspected engine bores,pistons, valves, etc by simply removing the sparkplugs & using an optical bore scope.

This is a fast, efficient way to verify a carbon build-up, scratched
cylinder wall,etc. I would demand that this be done before any attempt at denying your warranty is attempted.
 

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I also wondered if they allowed Anbreau to view the piston crowns and valves with a scope. From the description of the way this vehicle was driven I do not believe this alleged carbon build up can exist without an underlying cause.

As Eric L suggested, take it to an independent mechanic, hopefully you can get a referral to someone that can be trusted.

Pertaining to fuel type, I had the misfortune of being in the country and having to completely fill my tank with regular 87 as this was all that was available. To say the performance was sluggish would be a gross understatement. It was laboring making simple passes, I do not consider this aggressive driving. Yes it will burn regular without pinging but I don't think this level of performance was the intent for this engine. Kinda like using a race horse to pull a plow.

I do agree with the comments about burning premium in vehicles designed for regular as both my motorbike and snowmobile will not idle and load up when using premium indicating poor combustion at low rpm.
 

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Discussion Starter #19
This is turning out to be quite an adventure...

The Dealer cleaned the engine (soaking overnight), replaced the spark plugs, re-cleaned the throttle body, and changed the oil.

The Mechanics, Service Director, and myself test drove the vehicle and did not note any more pinging. I left the Dealership with a reminder that they just resolved the symptom but have not cured the disease and I strongly suspect that I will be back at my next 10K miles.

Well, after 30 minutes of driving on the highway and coming to my first stop, the pinging returns. Basically back to what it was last May (Thank you Mr. Murphy).

It all started this way. Engine must be warm (9 minutes exactly), start from a dead stop, when the RPM reaches 1750 the engine pings for 1 to 2 seconds then drops to 1250 and pinging goes away. If I continue accelerating past 1750, there will not be any pinging, at least for now. With time (if I go with history), the pinging will get louder and last longer and eventually will occur on all acceleration regardless of RPM and speed.

I can do stop and goes like this continuously with the same result. The engine does not ping on neutral at 1750 (no stress I guess).

I use 93 octane from various reputable gas stations. The next lower grade available is 89.

Nissan continues to recommend that I use manufacturer recommended fuel. They will not give me an octane rating.

Dealer wants to re-clean the engine. I want external diagnoses of the CPU and Sensors. Dealer is considering replacing the anti-knock sensor but needs Nissan's approval.

Nissan's approach is no error code - no problems.

I am escalating to next management layer at Nissan and researching on lemon law.

I am starting to wonder if I am not going crazy but I swear that this car did not ping the first 9000 files. This is getting way too complicated and I am out $600...

(In answer to the last question: Looking inside the piston via the spark plug hole with a light, I could see complete black coverage with oily (at least wet) lumps of deposits (one looked like the size of a dime)).
 
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