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Intermittent Engine Knocking on Idle


Neil

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'Intermittent' I hate that word....

 

On idle I occassionally hear a rythmic knocking coming from the bottom of the engine bay. It's a heavy knock.

 

When cold its not present - when very hot its not present. If I start the car about an hour after previously driving it, the knocking appears.

 

Took it into Nissan and was obviously embarrassed when the knock did not appear :blush::blush:

 

I'm using Titan Pro 5w-40 Oil of which I have been using for a couple of years so I don't think its this?

 

Chris S mentioned a thread suggesting Fuel Dampner but I have spent over an hour searching with no luck (this site has too much info sometimes ;) )

 

Do you think an ECU reset would help? If yes, what is the 'pedal dance' you learned guru's bang on about?

 

Any help would be appreciated please :)

 

Neil

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I have the same issue...when it knocks it seems as though the revs are jumping too but theres no movement on the rev meter. I can hear the exhaust babbling to the 'knocking' noise too.

 

Does that sound similar to your issue?

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I have the same issue...when it knocks it seems as though the revs are jumping too but theres no movement on the rev meter. I can hear the exhaust babbling to the 'knocking' noise too.

 

Does that sound similar to your issue?

 

Haven't noticed the revs jump or the exhaust babble mate?

 

Do you think its an 'East Midlands' thing ;)

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I have the same issue...when it knocks it seems as though the revs are jumping too but theres no movement on the rev meter. I can hear the exhaust babbling to the 'knocking' noise too.

 

Does that sound similar to your issue?

 

Haven't noticed the revs jump or the exhaust babble mate?

 

Do you think its an 'East Midlands' thing ;)

 

Dayummm!!! Just realised you're in Leicestershire! Where abouts are you???

 

Listen carefully, you'll notice a knock and like a mis-fire type noise which you'll hear through the exhaust too

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Markfield

 

I'll have a listen tomorrow...

 

It's been frustrating me ever since I got the car...I mentioned it on the forum a few times with no joy. It sounds as though you have the same issue.

 

Hopefully I can get to the bottom of it!

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:wave: hi guys, I swear there must be something in the fuel in leicester because I have the exact same sound, its never bothered me though. Nice to see some more peeps from leicester we should arrange a mini meet, I know there is a couple more from leicester too (racing green and CS)
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:wave: hi guys, I swear there must be something in the fuel in leicester because I have the exact same sound, its never bothered me though. Nice to see some more peeps from leicester we should arrange a mini meet, I know there is a couple more from leicester too (racing green and CS)

 

The thing is, when you've got music on etc you don't really notice it. Sometimes it really irritates me and is VERY noticeable!

 

When I switch the A/C on, it disappears!!

 

The exhaust blows inconsistently, it directly related to the knocking sound. It's like the car is idling so lean, it's close to cutting off, hence the splutter. I really hope I can get to the bottom of this!

 

It's weird only people from Leicester have noticed this :lol:

 

Yes we definitely need to arrange something, it's nice to know there's more members from Leicester!

 

CS is always down for a meet also!

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Are you using normal unleaded petrol? I noticed mine didn't run very smooth on normal, only use super now. Could be a simple as that.

 

I always use Shell V-Power in my car, I have never used any other fuel.

 

Yes, I've heard a few people mention their car runs rough when they use cheaper fuel.

 

The previous owner did switch between cheaper fuel to V-power though...

 

It is a good point though :thumbs:

 

As it disappears when the A/C is triggered, could it be related to the car idling at a too low rev? What rev is it meant to idle at? The car runs perfectly smooth with the A/C switched on.

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Are you using normal unleaded petrol? I noticed mine didn't run very smooth on normal, only use super now. Could be a simple as that.

 

I always use Shell V-Power in my car, I have never used any other fuel.

 

Yes, I've heard a few people mention their car runs rough when they use cheaper fuel.

 

The previous owner did switch between cheaper fuel to V-power though...

 

It is a good point though :thumbs:

 

As it disappears when the A/C is triggered, could it be related to the car idling at a too low rev? What rev is it meant to idle at? The car runs perfectly smooth with the A/C switched on.

 

It's always worth leaving the air-con on full-time as it does help the idle.

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Fuel damper came to mind but see this thread when it was finally diagnosed as the dual mass flywheel:

 

(terribleone's last post on that page ;) )

 

viewtopic.php?f=10&t=37826&hilit=fuel+damper&start=15

 

Thanks Colin - that's the fella (although my knocking is not as loud as terribleone's).

 

My car has a 5 year warranty which runs out this September so I think I'll visit Nissan Leicester to see if they can sort it ;)

 

One can dream...

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:wave: hi guys, I swear there must be something in the fuel in leicester because I have the exact same sound, its never bothered me though. Nice to see some more peeps from leicester we should arrange a mini meet, I know there is a couple more from leicester too (racing green and CS)

 

The thing is, when you've got music on etc you don't really notice it. Sometimes it really irritates me and is VERY noticeable!

 

When I switch the A/C on, it disappears!!

 

The exhaust blows inconsistently, it directly related to the knocking sound. It's like the car is idling so lean, it's close to cutting off, hence the splutter. I really hope I can get to the bottom of this!

 

It's weird only people from Leicester have noticed this :lol:

 

Yes we definitely need to arrange something, it's nice to know there's more members from Leicester!

 

CS is always down for a meet also!

 

Now you have explained it in a bit more detail, mine seems nowhere near as bad as this its more like this... Hmmmmmmmmm-duf-hmmmmmmmmmmmmmmmm-duf-hmmmmmmmm lol but that's how it sounds making the noise about every ten seconds, it does not seem like its on the verge of cutting out and the exhaust is not blowing either.

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:wave: hi guys, I swear there must be something in the fuel in leicester because I have the exact same sound, its never bothered me though. Nice to see some more peeps from leicester we should arrange a mini meet, I know there is a couple more from leicester too (racing green and CS)

 

The thing is, when you've got music on etc you don't really notice it. Sometimes it really irritates me and is VERY noticeable!

 

When I switch the A/C on, it disappears!!

 

The exhaust blows inconsistently, it directly related to the knocking sound. It's like the car is idling so lean, it's close to cutting off, hence the splutter. I really hope I can get to the bottom of this!

 

It's weird only people from Leicester have noticed this :lol:

 

Yes we definitely need to arrange something, it's nice to know there's more members from Leicester!

 

CS is always down for a meet also!

 

Now you have explained it in a bit more detail, mine seems nowhere near as bad as this its more like this... Hmmmmmmmmm-duf-hmmmmmmmmmmmmmmmm-duf-hmmmmmmmm lol but that's how it sounds making the noise about every ten seconds, it does not seem like its on the verge of cutting out and the exhaust is not blowing either.

 

Your description sounds exactly like mine, I think I was just over-exaggerating just to get the detail of the issue across :p

 

The 'Hmmmmmmmmm-duf-hmmmmmmmmmmmmmmmm-duf-hmmmmmmmm' happens to me also...

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Mine clunks occasionally on idle. It sounds like the release bearing clunking in between the normal whirring noise it makes. I find that the clunks coincide with the fans cutting in and out. I think that perhaps the electrical loading of the fans coming on increases the idle speed slightly (much like turning on the A/C) and then when they go off it drops back down again.

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Try cleaning the Maf sensor...... mine had a rough idle but was okay with aircon on. eventually found the Maf sensor had a bit of leaf in and around the hot wire element... cleaned it and the idle improved and no need for aircon to be on.... idle now totally reliable all this 15,000 miles ago. Worth a try...use brake cleaner or switch cleaner...(unless you too have a leaf!!!!!)

Good luck :thumbs:

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