possible fuel detonation problems?

[apm285]

I have been experiencing symptoms of like a grinding/clacking/knocking noise coming from the engine bay, but it only occurs when going up a hill on load at around about 2000rpm. I told my mechanic and he suspects without properly diagnosing it that it could be a fuel detonation. He advised to use high octane fuel which i have been doing. Here in Australia the lowest octane you can buy is 91% and our premiums are 98%-100% octane which i always use. He said to try a different brand like BP rather than Shell and see how that goes. I have had the car for 1 year and i always do city driving, the car never goes over 2000rpm.

What do you guys recommend? Can to much carbon build up because of not thrashing the car cause this? How about an upper engine cleaner?

Cheers

[infinitgkid]

possible fuel detonation?

hmm this is the first I've ever heard of a problem like this.

So I don't have anything for ya, but I'm sure someone will chime in a hopefully they'll have an answer

[SteveTheTech]

Although this seems like a straightforward conundrum there are so many variables that effect engine operation. Oil, Fuel, even Atmospheric conditions could cause what sounds like detonation, or a lean miss. Without seeing any of the data from the car under load I can only guess and give you a few things you should check.

When did you notice this happening? Randomly appeared or after service? What type of intake are you using and what type of air filter? What do you have for modifications if any?

The only advise I can pass along is find an respected Nissan service tech or at least someone with a Consult 2 or higher to look at the data from the engine. If you can give us a little more direct information we might be able to help.

[Jacko3]

What type of car do you drive????????? Is it an infiniti G35/Nissan 350GT???????????

If your car has a VQ35DE or VQ35HR engine, driving at 2,000 RPM or below means that you rarely drive beyond 45 miles per hour/66 kilometers per hour all day long. Such a low speed all the time will kill your VQ35DE or VQ35HR engine.

I don't beleive your engine is detonating. Your engine is suffering form a lack of serious driving. its just giving you signs that it needs to be flogged or openned up. Go out there and flog that car and make love to it like never before.

[pfarmer]

I have been experiencing symptoms of like a grinding/clacking/knocking noise coming from the engine bay, but it only occurs when going up a hill on load at around about 2000rpm. I told my mechanic and he suspects without properly diagnosing it that it could be a fuel detonation. He advised to use high octane fuel which i have been doing. Here in Australia the lowest octane you can buy is 91% and our premiums are 98%-100% octane which i always use. He said to try a different brand like BP rather than Shell and see how that goes. I have had the car for 1 year and i always do city driving, the car never goes over 2000rpm.

What do you guys recommend? Can to much carbon build up because of not thrashing the car cause this? How about an upper engine cleaner?

Cheers

Thrashing is overrated. Take the car in to a good shop that understands it and let the good doctor have a look at it. Could be several things, something simple like a bad or dirty plug, vacuum leaks, or something more complicated that needs to be looked at. In any case get it looked at soon before something possibly simple turned into something major.

Perry

[tollboothwilley]

why would you not drive your car over 2000 rpms??

That to me, is a problem in and of itself.

[infinitgkid]

conundrum

My new word of the week... thank you...

[G_whizz]

why would you not drive your car over 2000 rpms??

That to me, is a problem in and of itself.

How is that even possible??

[pfarmer]

How is that even possible??

I don't if it is. If so running under load while lugging is never a good idea.

However I don't think the fix is the reverse.

Perry

[Jacko3]

Thrashing the VQ engine is not overrated. I agree with you that the car may need to get checked.

Since I bought my G-25 coupe, when i don't drive it routinely or when i drive it gently, the car performs worse than when i thrash it. After a serious thrashing (6K - 7 K rpms all day long), everything seems to work excellently and marvellously---the shifting and engine response is almost god sent . I know the ECU has something to do with this, but then, i don't know of any other car that behaves the same way.

I have a 4 cylinder B-13 and it behaves more consistently than my G35 Coup, whether thrashed or not. To my B-13, thrashing is then really over-rated.

I do not beleive the VQ engines were totally designed with daily use in mind, especially the VQ 35 DE engines. However, Nissan adressed the daily use issue, somewhat, in the VQ35HR engines. For daily driving, I would always go for the VQ 35 HR engines---they are great.

[pfarmer]

Thrashing the VQ engine is not overrated. I agree with you that the car may need to get checked.

Since I bought my G-25 coupe, when i don't drive it routinely or when i drive it gently, the car performs worse than when i thrash it. After a serious thrashing (6K - 7 K rpms all day long), everything seems to work excellently and marvellously---the shifting and engine response is almost god sent . I know the ECU has something to do with this, but then, i don't know of any other car that behaves the same way.

I have a 4 cylinder B-13 and it behaves more consistently than my G35 Coup, whether thrashed or not. To my B-13, thrashing is then really over-rated.

I do not beleive the VQ engines were totally designed with daily use in mind, especially the VQ 35 DE engines. However, Nissan adressed the daily use issue, somewhat, in the VQ35HR engines. For daily driving, I would always go for the VQ 35 HR engines---they are great.

I stand by 'thrashing is overrated' based on the majority of my cars over the last 40+ years of driving experience have approached the 200k mark with several the 300k mark and a couple over the 300 k mark without major problems. You don't have to 'thrash' or 'flog' your car in order for it to be able to hit redline on demand without disintegration. Equally important is that you don't drive it consistantly at low speeds under load.

Going out and taking a car to red line which may have issues, could end up with serious damage to the engine such as broken rings or wrist pins due to piston slap. I don't believe the poster stated mileage for example. If ran at low speeds for an exceeding period of time and a problem such as cyclinder ridges exist with even a lit bit of slop at either end of the rods and you can end up with a very expensive repair bill compared with a moderate repair bill if you decide on the wrong type of external repair method.

I believe these engines do not have to be 'thrashed' or 'flogged' to perform very well over an extended period of time.

'Love is all you need'

Perry

[Sentientbydesign]

Jacko,

Stick to the facts

The VQ has been on Ward's 10 best list for 13(?) years now. The 3 liter V6 was in the Maxima back in 95. The 3.5L has been in Nissan/Infinitis since 2003 IIRC. There's nothing wrong with the engine and NO reason to suggest that it is not intended for daily driving or that it needs to be "thrashed/flogged" to perform correctly.

A bigger issue with your car is how you drive it, how you mod it, and the fact that the 6 speed manual is a loose, loud, dog.

[kmckis1029]

i agree with jacko3 that the vq35de is much smoother after some flogging in the upper rpms... its very weird to me also... yet satifing... but i wouldnt recommend flogging an engine that might have something wrong with it either...

if he is really driving under 2000 rpms why does he even own a G? vq35de is a high reving engine...

Plus i would think the ecu would adjust accordingly... then when you finally want to open the G's engine up the ecu doesnt have the best fuel/air map ready... thus some detonation... well just my guess...

[telcoman]

I stand by 'thrashing is overrated' based on the majority of my cars over the last 40+ years of driving experience have approached the 200k mark with several the 300k mark and a couple over the 300 k mark without major problems. You don't have to 'thrash' or 'flog' your car in order for it to be able to hit redline on demand without disintegration. Equally important is that you don't drive it consistantly at low speeds under load.

Going out and taking a car to red line which may have issues, could end up with serious damage to the engine such as broken rings or wrist pins due to piston slap. I don't believe the poster stated mileage for example. If ran at low speeds for an exceeding period of time and a problem such as cyclinder ridges exist with even a lit bit of slop at either end of the rods and you can end up with a very expensive repair bill compared with a moderate repair bill if you decide on the wrong type of external repair method.

I believe these engines do not have to be 'thrashed' or 'flogged' to perform very well over an extended period of time.

'Love is all you need'

Perry

pfarmer

I tend to agree with you. Thrashing a vehicle should not be necessary. I also had a few vehicles go over the 200k mile mark in my 40+ years of driving. The OP questioned the fuel and octane. I will turn 80k miles later this week with my 06 G and have only used regular 87 octane with never any ping or any other unusual noise under load going uphill so I don't think fuel is apm285's problem?

Perhaps the plugs are fouled by taking short trips and never having the engine reach operating temperature for a period of time? Inspecting the plugs might provide a clue to the problem? Perhaps there is water in the gas? A can of drygas is worth a try. I would also drive until the fuel warning light comes on and fill the tank at a station that pumps a lot of gas such as a truck stop.

My 100 mile round trips to work are under 3000 rpm between 75 -80 MPH in 6th gear.

As others have suggested, if it were me I would take it to a dealer & let them test drive it & check it out and also see if any trouble codes are in the system.

Telcoman

[pfarmer]

pfarmer

I tend to agree with you. Thrashing a vehicle should not be necessary. I also had a few vehicles go over the 200k mile mark in my 40+ years of driving. The OP questioned the fuel and octane. I will turn 80k miles later this week with my 06 G and have only used regular 87 octane with never any ping or any other unusual noise under load going uphill so I don't think fuel is apm285's problem?

Perhaps the plugs are fouled by taking short trips and never having the engine reach operating temperature for a period of time? Inspecting the plugs might provide a clue to the problem? Perhaps there is water in the gas? A can of drygas is worth a try. I would also drive until the fuel warning light comes on and fill the tank at a station that pumps a lot of gas such as a truck stop.

My 100 mile round trips to work are under 3000 rpm between 75 -80 MPH in 6th gear.

As others have suggested, if it were me I would take it to a dealer & let them test drive it & check it out and also see if any trouble codes are in the system.

Telcoman

I would definately take it into a good dealer, at least someone who understands the Infiniti. The last time I had something like this occur it turned out to be a cracked plug. Seemed fine at idle and lightly loaded. Heavy loads at lower RPMs and it presented itself. Spotted by looking at the ignition at night. Being a Jeep however made it a lot easier to see.

Just for the heck of it, on my 08 xs 2000 rpm equaled 50 mph in 5th gear (auto).

Perry

[apm285]

What is the highest octane rating you can purchase in the US.

Here in australia the lowest available is 91 and the highest which is Shell V power racing is 100 i usually fill up on just v power rated at 98.

Have you used ethanol on your G35 coupes before?

[kmckis1029]

v-power is 93 octane in GA... some states have higher octanes

lowest is 87 octane...

[leeG35]

How long has this been going on? You could have gotten a bad tank of gas, or accidentally filled up with regular. The G sedan can run on regular, but the G coupe requires premium.

It may be as simple as just keeping the rpm up on hills. These high revving engines will complain if forced to pull at a low rpms, as well they should!

As a side note: when comparing octane ratings between countries, be sure to compare ratings obtained by the same measurement method. There are a few ways to do it and in the US the octane on the pump is an average of the Research Octane Number (RON) and the Motor Octane Number (MON) or (R+M)/2.

[tollboothwilley]

What is the highest octane rating you can purchase in the US.

Here in australia the lowest available is 91 and the highest which is Shell V power racing is 100 i usually fill up on just v power rated at 98.

Have you used ethanol on your G35 coupes before?

+1

In utah you can get 85 octane

[telcoman]

+1

In utah you can get 85 octane

I think you can also have more than one wife although INMHO one is enough?

Telcoman

[Jacko3]

I stand by 'thrashing is overrated' based on the majority of my cars over the last 40+ years of driving experience have approached the 200k mark with several the 300k mark and a couple over the 300 k mark without major problems. You don't have to 'thrash' or 'flog' your car in order for it to be able to hit redline on demand without disintegration. Equally important is that you don't drive it consistantly at low speeds under load.

Going out and taking a car to red line which may have issues, could end up with serious damage to the engine such as broken rings or wrist pins due to piston slap. I don't believe the poster stated mileage for example. If ran at low speeds for an exceeding period of time and a problem such as cyclinder ridges exist with even a lit bit of slop at either end of the rods and you can end up with a very expensive repair bill compared with a moderate repair bill if you decide on the wrong type of external repair method.

I believe these engines do not have to be 'thrashed' or 'flogged' to perform very well over an extended period of time.

'Love is all you need'

Perry

There is something called limp mode in the G-35 or modern cars. If you thrash the car and it fails, it goes into limp mode. Cracked plugs is a rarity, as rare as winning a lottery. However, if it makes "apm285" happy, then they should take their car to the dealership to get it checked out. And, i wouldn't be climbing a hill with the G-35 at 2000 RPM, if I were "apm285". Never, ever! Give the car gas and use a lower gear to get to the top of the hill while spreading the load.

[pfarmer]

There is something called limp mode in the G-35 or modern cars. If you thrash the car and it fails, it goes into limp mode. Cracked plugs is a rarity, as rare as winning a lottery. However, if it makes "apm285" happy, then they should take their car to the dealership to get it checked out. And, i wouldn't be climbing a hill with the G-35 at 2000 RPM, if I were "apm285". Never, ever! Give the car gas and use a lower gear to get to the top of the hill while spreading the load.

Cracks in the insulator of plugs is not all that uncommon, certainly not as uncommon as winning a lottery, even a two buck lottery. As far as 'thrashing/flogging' a car, if it fails, then it certainly will go limp.

Perry

Perry

[leejoseph]

here is your problem right here. I'm going through wars with the dealership now.

Jan 08, I purchased a brand new 07 Infiniti (M35x) and for over a year I fought with the Infiniti services team to address a “rattling, pinging, rocks in a can” issue coming from the exhaust system beneath the front of the car. Finally it took the regional manager to come down after filing two complaints with the inter-circle consumer affairs department. From that point; it took both of us to go into the garage and actually have the tech take the "heat Shield" off and to our demise. We found that the small piece of material inside of it was deteriorated. He (Roger Gettler) made them order a new heat shield which corrected the issue. Outside of that; I had additional issues from the “middle headrest latch being broken, the wood molding on the driver side came a loose on the door, the controller in the passenger side mirror went out and the last straw was a rattling in the passenger door they could not fix and needed to replace the whole panel.

Now; the new and current general manger for Charles Barker Infiniti tried to ease my pain recently by working a deal on a 09 (M35 Sport). I have owned this car roughly two weeks and again the rattling issue has returned. I have had an intermitted issue with the passenger mirror when putting the car in reverse and the AC in the seat hardly works in this car.

File your complaints with NHTSA & BBB, I'm going through it with them now, because it's only been 3 months since I bought the car.

[Joey666Crack]

here is your problem right here. I'm going through wars with the dealership now.

Jan 08, I purchased a brand new 07 Infiniti (M35x) and for over a year I fought with the Infiniti services team to address a “rattling, pinging, rocks in a can” issue coming from the exhaust system beneath the front of the car. Finally it took the regional manager to come down after filing two complaints with the inter-circle consumer affairs department. From that point; it took both of us to go into the garage and actually have the tech take the "heat Shield" off and to our demise. We found that the small piece of material inside of it was deteriorated. He (Roger Gettler) made them order a new heat shield which corrected the issue. Outside of that; I had additional issues from the “middle headrest latch being broken, the wood molding on the driver side came a loose on the door, the controller in the passenger side mirror went out and the last straw was a rattling in the passenger door they could not fix and needed to replace the whole panel.

Now; the new and current general manger for Charles Barker Infiniti tried to ease my pain recently by working a deal on a 09 (M35 Sport). I have owned this car roughly two weeks and again the rattling issue has returned. I have had an intermitted issue with the passenger mirror when putting the car in reverse and the AC in the seat hardly works in this car.

File your complaints with NHTSA & BBB, I'm going through it with them now, because it's only been 3 months since I bought the car.

So wait, what does that have to do with the OP?

[Graflo]

Thrashing is overrated.

BLASPHEMY!!! HOW DARE YOU SIR?!

Yes there is something wrong with the op's car and he should not thrash it back to health...

But you only come this way once and our cars are here for enjoyment and excitement IMO. I enjoy hard acceleration from a stop... You enjoy having a car reach the +200K mark... To each his own I guess.

I say thrashing is underrated and should be done whenever the law permits.... or is out of site.

Within Saftey because I'm not talking street racing and I no Rice... So don't jump down my back for enjoying the HP.

Modified by Graflo at 12:25 PM 10/6/2009
Modified by Graflo at 12:26 PM 10/6/2009

[telcoman]

I have been experiencing symptoms of like a grinding/clacking/knocking noise coming from the engine bay, but it only occurs when going up a hill on load at around about 2000rpm. I told my mechanic and he suspects without properly diagnosing it that it could be a fuel detonation. He advised to use high octane fuel which i have been doing. Here in Australia the lowest octane you can buy is 91% and our premiums are 98%-100% octane which i always use. He said to try a different brand like BP rather than Shell and see how that goes. I have had the car for 1 year and i always do city driving, the car never goes over 2000rpm.

What do you guys recommend? Can to much carbon build up because of not thrashing the car cause this? How about an upper engine cleaner?

Cheers

Does anyone know the elevation of the op location?

[Joey666Crack]

Sydney Australia I'm pretty sure is close to sealevel .