| theeduc8tor |
| I refuse to put premium unleaded gasoline in my '05 Murano because the NPR Car Guys say it's not necessary to spend the extra dime per gallon. However, I have piston slap pretty bad. I can hear it during any type of acceleration. Is this happening to everyone? Or has everyone drank the Kool-Aid on that premium gas requirement? Nissan dealer says, "eh... so it knocks." |
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| benhui86 |
i'd think you better put premium back in it bc knocking can do some pretty bad damage in the long run..... or maybe you can try plus instead....
ive noticed that 87 gives you a lot worst gas mileage so while you are spending less at the pump.... you have to visit the pump more often..... so it cost you similar in the end..... why bother risking your engine.... |
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| hfelknor |
I wouldn't worry about it.
I would let it detonate itself to pieces.
After all, the car guys will reimburse you if they are wrong (again), won't they? ;)
Actually you need to take it in.
Piston slap has nothing to do with choice of gas.
And it is very serious.
And if it is not piston slap, but pre detonation, then you may have a bad knock sensor.
The MO should run perfectly acceptable (without extra load, without towing, ets) with reg gas.
But if it doesn't, and there is nothing specifically wrong, you would have to run a higher octane. |
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| njjoe |
"Piston Slap"?? Trust me, what you are hearing is most definitely not "piston slap". Piston slap occurs when an improperly sized piston is mated to a cylinder. The VQ is a very well-engineered engine. You will not experience piston slap in the MO.
What you are experiencing is engine knock.
-njjoe |
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| DMordarski |
| all the 3.5s require at lest 89, that what I run... but it has to be a name brand not a cheapi |
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| njjoe |
quote:
Originally posted by DMordarski
all the 3.5s require at lest 89
That is a false statement.
The VQ is designed to run with gasoline with a minimum octane rating of 87 (Regular Grade).
-njjoe |
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| bob1 |
I have or had 3 cars with the VQ engine. My 3.5 Altima now in my sons hand, my Murano and my Infiniti G-35 coupe.
All the books call for premium gas with the VQ. It is my understanding that the car will have to alter itself electronically to adapt to anything less than premium.
I run 93 octane in all the cars and a couple times I tried a lower octane and on an uphill climb, I heard some pings.
In the big picture I usually tank up when I need about 15 gallons. I never run her dry. High test is 20 cents more a gallon so that's 3 bucks.
Just my opinion, I'm spending the 3 bucks to prevent the pings and I'm sure it's not great for the engine either when that is happening.
Bob1 |
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| Eric L. |
The only gas your Murano requires is 87 octane. If you are getting knocking on 87, take it to the dealer and have them use the Consult II to verify that the timing and knock sensor is functioning correctly.
As for whether premium 91-94 octane increases performance, the answer is almost certainly yes, but not to the extent that most people think. Nissan rates some of their engines on regular fuel and others on premium fuel. The difference in horsepower is probably less than 10hp between the two fuel types. A good illustration is this wiki article on Nissan's 5.6L V8 (scroll all the way to bottom).
http://en.wikipedia.org/wiki/Nissan_VK_engine
As for me, I don't mind paying an extra $10 or so per month to fill up on premium vs regular. As gas prices go higher, the marginal cost of purchasing premium actually decreases. If gas were $1 a gallon, ok then maybe 20% more is a waste of money. But at $4 a gallon, 20 cents is just 5%. |
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| theeduc8tor |
Allright, so I will go to the dealer to check for those sensor issues (knock sensor). I just can't imagine that 2.0 octane increase will eliminate this issue. The gas door says "recommended" afterall! Like red lights, it's merely a suggestion.
So...has anyone had similar issues?
P.S. I have no justification to give to the household CFO for the purchase of premium unleaded. |
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| DMordarski |
| My maxima pinged hard on 87, so I ran 89 all the time, habit just carried over to the mo so I can't say that I've had any pinging issues |
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| bob1 |
quote:
So...has anyone had similar issues?
P.S. I have no justification to give to the household CFO for the purchase of premium unleaded. [/B]
We had a widespread debate here some time ago. We have to 2 camps that are like Republican and Democrats that will not agree. heehee.
Like I said above, I see it's in my owners manual for some reason on all 3 of my VQ engine cars calling for high test. I tried the lower stuff and I got pings going uphill.
Sure maybe the engine will eventually adjust but I did not care to wait. I went back to the "good stuff."
Bob1 |
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| zebelkhan |
quote:
Originally posted by theeduc8tor
The gas door says "recommended" afterall! Like red lights, it's merely a suggestion
That wuz teh funneh....:2: |
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| mgthe3 |
quote:
Originally posted by Eric L.
As for whether premium 91-94 octane increases performance, the answer is almost certainly yes, but not to the extent that most people think. Nissan rates some of their engines on regular fuel and others on premium fuel. The difference in horsepower is probably less than 10hp between the two fuel types. A good illustration is this wiki article on Nissan's 5.6L V8 (scroll all the way to bottom).
I would think they rated the Mo VQ on premium.
educ8tor: The VQ is a 10.3 to 1 compression ratio engine.
It wants premium, period. Anything higher than 9.7 to one ratio wants premium or it WILL knock.
The VQ will however, upon sensing knock, retard it's ignition to run on inferior gas. That seems crazy to me.
I have heard Mo's on regular, they sounded awful! Horrible knocking!
Want knock? Run regular.
Don't want knock? Run premium.
I have had two Mos now. Neither one has knocked from day 1.
I run premium.
:D |
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| theeduc8tor |
| Allright, so I phoned my Nissan dealer and mentioned that I wanted my "pings" checked when I come in for my warranty work. Dealer recommended a fuel-injector cleaner (30K service) that would probably solve the problem. However, dealer also mentioned that Nissan Tech support would say that I need to use Premium Unleaded fuel to rid the problem! Argh! Allright guys...I'm going to do it! I might be asked to pack up my stuff and move out of my house, but I'm going to fill-up with premium. |
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| njjoe |
quote:
Originally posted by mgthe3
I have heard Mo's on regular, they sounded awful! Horrible knocking!
Want knock? Run regular.
Don't want knock? Run premium.
mg-
I use mostly regular-grade gasoline in my MO and have never experienced engine knock even on hot days. It runs just fine on regular.
I had a rental MO for about a month, fed it regular, and never experienced knocking.
-njjoe |
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| njjoe |
quote:
Originally posted by theeduc8tor
Dealer recommended a fuel-injector cleaner (30K service) that would probably solve the problem.
theeduc8tor -
There should be no reason to use a fuel injector cleaner after just 30,000 miles, unless you have been buying your gas in some third-world country.
Have the dealer check the knock sensors to ensure they are functioning properly.
-njjoe |
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| mgthe3 |
Maybe I should have video'd the pinging Mo's I have seen.
Maybe you drive yours differently Joe.
If you need knock sensors to retard the ignition when it knocks, why run something that makes it knock to begin with?
A Hummer can drive with multiple nails in it's tires with it's on board tire inflators. But I don't think I would go out of my way to drive over scrap boards in the road.
:2: |
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| DentsandDings |
| I had noises coming from mine under low acceleration when I ran 87 in it and I started running 89 all the time and after a few tanks it stopped, I took it into the dealer and had them check it and they are idiots but thats what they told me to do and it seemed to have fixed it. I have an 05 SL AWD wit 102k on it |
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| ekaxel |
On & on & on....
More threads about this than any other topic.
I personally use regular most of the time. never a ping.
Premium increases my mileage about 2 mpg ON THE HIGHWAY. virtually no difference in town.
I do note a slight performance increase when using premium, not enough to justify the cost.
As an aside: I would NEVER EVER buy premium from a station where the difference exceeded $0.20/gal.
If it makes you feel better to use premium, by all means do it! |
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| njjoe |
My MO is now two and half years old and starting to show it's age. :( The steering feels looser, the headlights are no longer as bright as they once were, and the radio picks up nothing but static. Then the other day I decided to tank-up with Premium gas and lo and behold the steering has firmed up, the headlights are now like searchlights and the radio receives in HD!! :D I'm a convert!! Nothing but premium for my MO now!!
-njjoe |
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| kerpal |
quote:
Originally posted by hfelknor
I wouldn't worry about it.
I would let it detonate itself to pieces.
After all, the car guys will reimburse you if they are wrong (again), won't they? ;)
Actually you need to take it in.
Piston slap has nothing to do with choice of gas.
And it is very serious.
And if it is not piston auto body part slap, but pre detonation, then you may have a bad knock sensor.
The MO should run perfectly acceptable (without extra load, without towing, ets) with reg gas.
But if it doesn't, and there is nothing specifically wrong, you would have to run a higher octane.
I still think its the Piston bro.. Or the place where the piston is located.. forgot the name.. Piston blok? |
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| Eric L. |
quote:
Originally posted by kerpal
I still think its the Piston bro.. Or the place where the piston is located.. forgot the name.. Piston blok?
I think you are referring to the cylinder. :) |
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| brandonsride |
| My dealer said there was a 2 degree adjustment and was going to try this on my MO at my last service. If he did anything it didn't may a bit of difference, I personally don't think anything was even done! I still get the knock at low acceleration and I have always used premium gas. Has anyone heard of this?, and if so how can one attempt this procedure? I am planning on doing my short services and have access to a variety of tools. Any help/advice would be appreciated. Thanks to all. At present I have 28K plus and thing I need to do other then what book suggest? |
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| bob1 |
[QUOTE, I personally don't think anything was even done! I still get the knock at low acceleration and I have always used premium gas. Has anyone heard of this? [/B][/QUOTE]
Any chance at all you have what I had. I have a thread in Problems and it's a sticky.
Here is an excerpt of my description.
http://nissanmurano.org/forums/show...?threadid=10126
Got to the point where the MO at idle in gear started to sound like a 1974 used Chevy Pick-up with 330,000 miles.
Finally when I could isolate the noise as being in the cabin, I went to Nissan where a very good tech came out, listened and then brought out a stethoscope rod thing-a-ma-jig.
He had me listen to the Fuel Damper which sits in the back near the firewall. Clank, clank, clank I heard very loudly.
I said Bingo!
If I'm not clear, the noise was in the back of the engine compartment but really heard while in the cabin with doors closed.
It was clack-clack-clack, really heard more at idle, in gear as when waiting for a stop light.
Bob1 |
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