M47 Diesel Engine Whine / Whistle On The Overun - Page 17

HarryM1BYT · 12th March 2015, 09:35

Thanks for the reminder, mine has all but disappeared. I paid particular attention yesterday and it was just barely audible. Had I not heard it before, I certainly would not have noticed it.

When got the car, it was quite audible and noticeable, though not loud.

So something has changed over the years.

Its a monotone whine, which appears on the overrun only and only when the engine is engine braking, but I could reproduce it briefly by blipping the throttle when stationary.

It is definitely around the HP mechanical pump area and according to I think Jules, swapping the later pump for an older model cures it.

rovexCDTi · 12th March 2015, 09:59

Mine has the older system, so its not that.

rovexCDTi · 8th June 2015, 12:22

Just a little test. Its been reported that its a 1Khz whine. This is 1KHz..

https://www.youtube.com/watch?v=HMHxn7Wlyxo

The noise mine makes is nearer to 500hz..

https://www.youtube.com/watch?v=TKITEWX0qY0

Can anyone confirm which tone their noise is.

HarryM1BYT · 8th June 2015, 12:47

Quote:

Originally Posted by rovexCDTi

Just a little test. Its been reported that its a 1Khz whine. This is 1KHz..

https://www.youtube.com/watch?v=HMHxn7Wlyxo

The noise mine makes is nearer to 500hz..

https://www.youtube.com/watch?v=TKITEWX0qY0

Can anyone confirm which tone their noise is.

Its difficult to decide, because its not a pure tone, nor a sinewave. It was probably me who suggested it was around 1KHz.

Must admit I no longer hear mine, I seem to have filtered it out in my ears

It was just a noise I heard, when I first bought the car and found it curious. It was never, ever intrusive.

I will try next time I use the car, to see if it does still make the noise.

rovexCDTi · 8th June 2015, 12:58

Having huge difficulty finding out what my noise it. Its very loud at times, off throttle, and near the 500Hz above and a distinct woooo with a sharp end rather than a fade out. It coming from the turbo area.

I heard some odd noises coming form turbos before but nothing like this, it doesn't seem to match any sort of turbo wear noise, or wastegate noise.

Initially I thought it was diff or gear whine, but it happens even if not moving, clutch up or down and its a constant tone, not speed dependant, so I doubt its a tensioner or the water pump.

My only guess now is exhaust related, sometimes I do have excessive noise when revved quite high when cold, which goes once warm.

Jules · 8th June 2015, 13:08

I suggested 1Khz in the 1st post of this very thread ( can't believe how long ago that was now 2007!!!) but it was only a guess at the time until I got chance to scope the signal.

500 hz is probably the same noise you are experiencing.
It the waveform fed the HP reg from the ECM

rovexCDTi · 8th June 2015, 13:17

I have the older 2 pump system not the facelift one and there is no noise coming from that area, only from the turbo, possibly the water pump area.

I have recorded the noise from within the car, its the woo near the end of the clip (around 8 to 10 second mark), faint, but much louder in reality.

https://www.dropbox.com/s/29r0bj21j0...40739.amr?dl=0

HarryM1BYT · 8th June 2015, 14:05

I can't do anything with the recording - amr???

Our noise only occurs when on the over run, engine being driven by the momentum of the car. Irrespective of the engine speed, the noise is a constant frequency and volume level. It disappears, the instant you touch the accelerator, make a demand for fuel.

rovexCDTi · 8th June 2015, 14:08

Plays on anything thats not windows media player really. VLC/MPC should play it. Ill see if i can convert it to mp3.

Mine does it even stationary, just off throttle as the revs drop.

rovexCDTi · 8th June 2015, 14:10

https://www.dropbox.com/s/587wokgs5z...40739.mp3?dl=0

12th March 2015, 09:35	#161
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	Thanks for the reminder, mine has all but disappeared. I paid particular attention yesterday and it was just barely audible. Had I not heard it before, I certainly would not have noticed it. When got the car, it was quite audible and noticeable, though not loud. So something has changed over the years. Its a monotone whine, which appears on the overrun only and only when the engine is engine braking, but I could reproduce it briefly by blipping the throttle when stationary. It is definitely around the HP mechanical pump area and according to I think Jules, swapping the later pump for an older model cures it. __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.

12th March 2015, 09:59	#162
rovexCDTi This is my second home MG ZT+ 135 Join Date: Jan 2011 Location: Exeter Posts: 3,626 Thanks: 9 Thanked 42 Times in 26 Posts	Mine has the older system, so its not that. __________________ [SIGPIC][/SIGPIC]

8th June 2015, 12:22	#163
rovexCDTi This is my second home MG ZT+ 135 Join Date: Jan 2011 Location: Exeter Posts: 3,626 Thanks: 9 Thanked 42 Times in 26 Posts	Just a little test. Its been reported that its a 1Khz whine. This is 1KHz.. https://www.youtube.com/watch?v=HMHxn7Wlyxo The noise mine makes is nearer to 500hz.. https://www.youtube.com/watch?v=TKITEWX0qY0 Can anyone confirm which tone their noise is. __________________ [SIGPIC][/SIGPIC]

8th June 2015, 12:58	#165
rovexCDTi This is my second home MG ZT+ 135 Join Date: Jan 2011 Location: Exeter Posts: 3,626 Thanks: 9 Thanked 42 Times in 26 Posts	Having huge difficulty finding out what my noise it. Its very loud at times, off throttle, and near the 500Hz above and a distinct woooo with a sharp end rather than a fade out. It coming from the turbo area. I heard some odd noises coming form turbos before but nothing like this, it doesn't seem to match any sort of turbo wear noise, or wastegate noise. Initially I thought it was diff or gear whine, but it happens even if not moving, clutch up or down and its a constant tone, not speed dependant, so I doubt its a tensioner or the water pump. My only guess now is exhaust related, sometimes I do have excessive noise when revved quite high when cold, which goes once warm. __________________ [SIGPIC][/SIGPIC]

8th June 2015, 13:08	#166
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	I suggested 1Khz in the 1st post of this very thread ( can't believe how long ago that was now 2007!!!) but it was only a guess at the time until I got chance to scope the signal. 500 hz is probably the same noise you are experiencing. It the waveform fed the HP reg from the ECM __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

8th June 2015, 13:17	#167
rovexCDTi This is my second home MG ZT+ 135 Join Date: Jan 2011 Location: Exeter Posts: 3,626 Thanks: 9 Thanked 42 Times in 26 Posts	I have the older 2 pump system not the facelift one and there is no noise coming from that area, only from the turbo, possibly the water pump area. I have recorded the noise from within the car, its the woo near the end of the clip (around 8 to 10 second mark), faint, but much louder in reality. https://www.dropbox.com/s/29r0bj21j0...40739.amr?dl=0 __________________ [SIGPIC][/SIGPIC] Last edited by rovexCDTi; 8th June 2015 at 13:19..

8th June 2015, 14:05	#168
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	I can't do anything with the recording - amr??? Our noise only occurs when on the over run, engine being driven by the momentum of the car. Irrespective of the engine speed, the noise is a constant frequency and volume level. It disappears, the instant you touch the accelerator, make a demand for fuel. __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.

8th June 2015, 14:08	#169
rovexCDTi This is my second home MG ZT+ 135 Join Date: Jan 2011 Location: Exeter Posts: 3,626 Thanks: 9 Thanked 42 Times in 26 Posts	Plays on anything thats not windows media player really. VLC/MPC should play it. Ill see if i can convert it to mp3. Mine does it even stationary, just off throttle as the revs drop. __________________ [SIGPIC][/SIGPIC]

8th June 2015, 14:10	#170
rovexCDTi This is my second home MG ZT+ 135 Join Date: Jan 2011 Location: Exeter Posts: 3,626 Thanks: 9 Thanked 42 Times in 26 Posts	https://www.dropbox.com/s/587wokgs5z...40739.mp3?dl=0 __________________ [SIGPIC][/SIGPIC]