Strange fluffing sound under load?
Discussion
I'm a bit worried, I had my exhaust welded to cure a leak after grounding out a few months back. But I'm not sure if this new sound is anything to do with that anyway.
It's a "flaffing" sort of sound, and it only happens when I'm accelerating very hard, under load, I've felt around the manifold, checked all joins, underneath as well, and can't feel anything blowing on tick over.
It's really quite disturbing when accelerating, it's like a sort of hollow sound, I'm going to take it in again yo have it looked at, but was just wondering if anything else apart from a leaky exhaust could cause this sound?
It's a "flaffing" sort of sound, and it only happens when I'm accelerating very hard, under load, I've felt around the manifold, checked all joins, underneath as well, and can't feel anything blowing on tick over.
It's really quite disturbing when accelerating, it's like a sort of hollow sound, I'm going to take it in again yo have it looked at, but was just wondering if anything else apart from a leaky exhaust could cause this sound?
Jobster said:
you sure that all cylinders fire under load?
Thanks, no, I'm not sure, you may have hit on something here, as I think there may be a drop in power on acceleration. This is serious, and I've got to get it checked out. If it is misfiring under load only, just wondering what to look for here?Edited by griff59 on Sunday 13th January 17:39
It can be the coil breaking down as the rate of sparks increases with engine speed or just a bad connection etc.
Does it happen straight away or once it’s hot as that’s often when a coil will start to fail.
Try starting it from cold, drive under load immediately then pull over, all within a minute or so and carefully check if one exhaust header is cooler but be careful not to burn yourself!
Others will have a better test I’m sure
Or check plugs for one that looks wet.
Does it happen straight away or once it’s hot as that’s often when a coil will start to fail.
Try starting it from cold, drive under load immediately then pull over, all within a minute or so and carefully check if one exhaust header is cooler but be careful not to burn yourself!
Others will have a better test I’m sure
Or check plugs for one that looks wet.
Classic Chim said:
It can be the coil breaking down as the rate of sparks increases with engine speed or just a bad connection etc.
Does it happen straight away or once it’s hot as that’s often when a coil will start to fail.
Try starting it from cold, drive under load immediately then pull over, all within a minute or so and carefully check if one exhaust header is cooler but be careful not to burn yourself!
Others will have a better test I’m sure
Or check plugs for one that looks wet.
Thanks, I'm going to buy a temperature gun, its at times like this they come in useful!Does it happen straight away or once it’s hot as that’s often when a coil will start to fail.
Try starting it from cold, drive under load immediately then pull over, all within a minute or so and carefully check if one exhaust header is cooler but be careful not to burn yourself!
Others will have a better test I’m sure
Or check plugs for one that looks wet.
I'm not at home right now, but when I get back I'm going to check wiring/connections, and the coil, as you said.
I think, it doesn't happen straight away, the car drives great on start up, but after a good few miles things start to go awry.
griff59 said:
I'm a bit worried, I had my exhaust welded to cure a leak after grounding out a few months back. But I'm not sure if this new sound is anything to do with that anyway.
It's a "flaffing" sort of sound, and it only happens when I'm accelerating very hard, under load, I've felt around the manifold, checked all joins, underneath as well, and can't feel anything blowing on tick over.
It's really quite disturbing when accelerating, it's like a sort of hollow sound, I'm going to take it in again yo have it looked at, but was just wondering if anything else apart from a leaky exhaust could cause this sound?
This is not a misfire, its the classic sound of an exhaust leak, you actually describe the sound perfectly so I am 100% sure this is what you're hearing.It's a "flaffing" sort of sound, and it only happens when I'm accelerating very hard, under load, I've felt around the manifold, checked all joins, underneath as well, and can't feel anything blowing on tick over.
It's really quite disturbing when accelerating, it's like a sort of hollow sound, I'm going to take it in again yo have it looked at, but was just wondering if anything else apart from a leaky exhaust could cause this sound?
To understand why it only makes this noise when the engine is under load you must first understand what happens when an internal combustion engine loads up. What happens is your cylinder pressures rocket up at a dramatic rate, as the pressures increase in the combustion chamber they find their way out of gaps the gasses just passed over under normal driving.
This is why you only get the "flaffing" sound when you put the engine under load, "flaffing" is of course not a word but it should be because it perfectly describes the sound of an engine under load where the high pressure gasses are finding or forcing a route to atmosphere that is just not found when combustion pressures are lower under normal driving.
Nice descriptive and creative use of the English there OP, "flaffing" is now my go to new word for exhaust leaks under load
ChimpOnGas said:
This is not a misfire, its the classic sound of an exhaust leak, you actually describe the sound perfectly so I am 100% sure this is what you're hearing.
To understand why it only makes this noise when the engine is under load you must first understand what happens when an internal combustion engine loads up. What happens is your cylinder pressures rocket up at a dramatic rate, as the pressures increase in the combustion chamber they find their way out of gaps the gasses just passed over under normal driving.
This is why you only get the "flaffing" sound when you put the engine under load, "flaffing" is of course not a word but it should be because it perfectly describes the sound of an engine under load where the high pressure gasses are finding or forcing a route to atmosphere that is just not found when combustion pressures are lower under normal driving.
Nice descriptive and creative use of the English there OP, "flaffing" is now my go to new word for exhaust leaks under load
Many thanks, that's what I thought initially, and there was a leak that was repaired a few months back, it's leaking again obviously. It was welded, but I think gaskets may need replacing. Flaffing is the only way I could possibly describe this sound, it's not "fluffing" that's too soft, it's a bit like beating a hard pillow with a piece of wood I should imagine, it's a much harder sound than "fluffing"To understand why it only makes this noise when the engine is under load you must first understand what happens when an internal combustion engine loads up. What happens is your cylinder pressures rocket up at a dramatic rate, as the pressures increase in the combustion chamber they find their way out of gaps the gasses just passed over under normal driving.
This is why you only get the "flaffing" sound when you put the engine under load, "flaffing" is of course not a word but it should be because it perfectly describes the sound of an engine under load where the high pressure gasses are finding or forcing a route to atmosphere that is just not found when combustion pressures are lower under normal driving.
Nice descriptive and creative use of the English there OP, "flaffing" is now my go to new word for exhaust leaks under load
I'm taking the car in for a service soon, so I'll get them to give it a good once over.
Edited by griff59 on Wednesday 16th January 10:58
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