M47 Diesel Engine Whine / Whistle On The Overun - Page 18

HarryM1BYT · 8th June 2015, 14:20

Quote:

Originally Posted by rovexCDTi

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

Mine did too, just a matter of getting enough revs on the engine, to be able to close the throttle and have it not using fuel for a fraction of a second - then you hear the noise briefly, until it drops to a tick over and begins consuming fuel again.

It was reputed not to affect the early HP pumps, but there was something about the fuel pipe length or routing too.

Some one suggested it was a sealing washer in the pump which vibrated, but then promptly disappeared when asked for more information.

Not sure whether adding 2T to my diesel cured it, or I simply stopped hearing it.

rovexCDTi · 8th June 2015, 14:27

Ive ordered a mechanics stethoscope to try to trace it further. Its just odd that the noise isnt coming from anywhere near any line or the HP fuel pump, but from the back of the engine on the drivers side. Thee is no way I can stop hearing it, its really loud

HarryM1BYT · 8th June 2015, 14:42

Quote:

Originally Posted by rovexCDTi

Ive ordered a mechanics stethoscope to try to trace it further. Its just odd that the noise isnt coming from anywhere near any line or the HP fuel pump, but from the back of the engine on the drivers side. Thee is no way I can stop hearing it, its really loud

The fuel pipes are maybe carrying the noise to the drivers side?

It varies considerably from car to car, how loud it is. Mine never was that loud, just about noticeable with the windows open.

rovexCDTi · 8th June 2015, 15:32

I wont say it definitely isnt the fuel pump until I get the stethoscope, but i have had my ear on the injector rail and pipes with the cover off and nothing was coming from anything there. The noise is actually almost inaudable when at the front of the engine, the HP pump was the first thing I suspected after reading this tread so went there first.

The noise is seemingly louder in the car that outside, even with the bonnet up, coming from the drivers foot well.

I suppose it might be a pulley, and be a weird resonance. The belts and the crank pulley are new though.

karolj · 3rd August 2015, 21:44

Hi! My 75 does the same. But... yesterday I've replaced my fuel filter and guess what? This weird whining noise just dissapeared. No matter if engine is cold or warm - there is just no whining sound! But after a 50km on new filter the whining sound got back ;/
This sound is only on overrun, so pobably engine is not using any fuel at this moment. My both filters (the previous one and the current one) is made by Knecht.
I'll probably change my fuel filter to another brand, maybe MANN. What do you think? What filters do you use?

T-Cut · 3rd August 2015, 21:51

This is a note I made in 2011. I haven't read this thread completely, so perhaps it's been discussed already. It's compiled from various discussions on this subject.

If the noise is heard on engine over-run as it slows down after blipping the throttle and it's a later model 131 diesel and it has a single fuel pump, then statistically, it will be high pressure fuel resonance from the pressure regulator. It's become a well discussed issue here and there and there does seem to be a diagnostic test suggested by Jules. You need to be driving the car in a safe location and adjust the conditions so the noise is obvious to you. If you then turn off the ignition and the noise instantly stops, then it's high pressure fuel resonance.
Although there are mixed results on fixing the problem, it will apparently be eliminated by replacing the HP regulator with the older version. Another fix is reported by simply putting a layer of Hermatite gasket goo between the regulator mounting plate and the HP pump. I also understand the noise has been discussed here before and a possible fix suggested. A judicious word search should locate it all.

and..

The test from Jules' experiments identifies the regulator as the cause. Your car fits all the other coincidental facts which focus the likelyhood of this as the cause. Though there has been discussion on this forum, it's all broadly saying 'I have that too, but how is it fixed?' I believe nobody here has the answer. However, the other forum has more practical evidence pointing to the regulator. It was apparently changed around the facelift introduction. The same noise is emitted by BMWs using the M47 engine. In facelifts, they seem to have fitted a different HP regulator to the HP pump, or there was a change in the ECU's PWM signal to the regulator. Using a stethoscope, the noise seems concentrated on the fuel return pipe on the regulator. Inside, it seems to come from behind the dash. It's only apparent under no-load conditions between 1500 and 3000 rpm.

EDIT: Having gone to the start, I see the notes above are taken from this same thread, so not much help really.

daznkel · 3rd August 2015, 22:17

Mine has made this noise since I have owned it. I just put up with it now. But at times it does my head in!

Phil th Barrow · 18th August 2015, 20:15

Quote:

Originally Posted by karolj

Hi! My 75 does the same. But... yesterday I've replaced my fuel filter and guess what? This weird whining noise just dissapeared. No matter if engine is cold or warm - there is just no whining sound! But after a 50km on new filter the whining sound got back ;/
This sound is only on overrun, so pobably engine is not using any fuel at this moment. My both filters (the previous one and the current one) is made by Knecht.
I'll probably change my fuel filter to another brand, maybe MANN. What do you think? What filters do you use?

Mine wines.. 04 conni cdti. I replaced fuel filter and wine went. Came back after 1000 odd miles. Filling tank full of fuel helped to as it only seemed to do it on below half full. But this could be a coincidence. Noise is back all th time now th warmer weather is here. Whifey carnt hear it at all in passenger seat.

karolj · 20th August 2015, 21:59

So maybe the problem is dying fuel pump under the rear seat?

Phil th Barrow · 23rd August 2015, 16:40

Maybe dying fuel pump.
But mine appears to wines o/s and in front under bonnet on over run. Today it was running very low on fuel and wining . Only said 6 miles range when parked up hill in drive. Drove it a few miles and it said 41 miles range. This is normal. Put 55 litres in it and wine went all together in my 21 mile run around I did after. Jules thinks its HP rail resonance especially with warm diesel in it.

8th June 2015, 14:27	#172
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	Ive ordered a mechanics stethoscope to try to trace it further. Its just odd that the noise isnt coming from anywhere near any line or the HP fuel pump, but from the back of the engine on the drivers side. Thee is no way I can stop hearing it, its really loud __________________ [SIGPIC][/SIGPIC]

8th June 2015, 15:32	#174
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 wont say it definitely isnt the fuel pump until I get the stethoscope, but i have had my ear on the injector rail and pipes with the cover off and nothing was coming from anything there. The noise is actually almost inaudable when at the front of the engine, the HP pump was the first thing I suspected after reading this tread so went there first. The noise is seemingly louder in the car that outside, even with the bonnet up, coming from the drivers foot well. I suppose it might be a pulley, and be a weird resonance. The belts and the crank pulley are new though. __________________ [SIGPIC][/SIGPIC]

3rd August 2015, 21:51	#176
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	This is a note I made in 2011. I haven't read this thread completely, so perhaps it's been discussed already. It's compiled from various discussions on this subject. If the noise is heard on engine over-run as it slows down after blipping the throttle and it's a later model 131 diesel and it has a single fuel pump, then statistically, it will be high pressure fuel resonance from the pressure regulator. It's become a well discussed issue here and there and there does seem to be a diagnostic test suggested by Jules. You need to be driving the car in a safe location and adjust the conditions so the noise is obvious to you. If you then turn off the ignition and the noise instantly stops, then it's high pressure fuel resonance. Although there are mixed results on fixing the problem, it will apparently be eliminated by replacing the HP regulator with the older version. Another fix is reported by simply putting a layer of Hermatite gasket goo between the regulator mounting plate and the HP pump. I also understand the noise has been discussed here before and a possible fix suggested. A judicious word search should locate it all. and.. The test from Jules' experiments identifies the regulator as the cause. Your car fits all the other coincidental facts which focus the likelyhood of this as the cause. Though there has been discussion on this forum, it's all broadly saying 'I have that too, but how is it fixed?' I believe nobody here has the answer. However, the other forum has more practical evidence pointing to the regulator. It was apparently changed around the facelift introduction. The same noise is emitted by BMWs using the M47 engine. In facelifts, they seem to have fitted a different HP regulator to the HP pump, or there was a change in the ECU's PWM signal to the regulator. Using a stethoscope, the noise seems concentrated on the fuel return pipe on the regulator. Inside, it seems to come from behind the dash. It's only apparent under no-load conditions between 1500 and 3000 rpm. EDIT: Having gone to the start, I see the notes above are taken from this same thread, so not much help really. Last edited by T-Cut; 3rd August 2015 at 21:56..

3rd August 2015, 22:17	#177
daznkel Posted a thing or two 04 MG ZT+ 190 XPG & 99 (T) Dealer Launch 75 V6 Connie Auto Join Date: Oct 2012 Location: Plymouth Posts: 1,080 Thanks: 615 Thanked 456 Times in 309 Posts	Mine has made this noise since I have owned it. I just put up with it now. But at times it does my head in! __________________ Click HERE To Be Added To The South West Members Location Map Upgrades/Mods so far: Custom Angel Eye DRL's, MG7 Rear lights, Custom Door Cards, MGR Plates, Red Alcantara Seats, Black Oak Dash, Powerflex bushes, Plenum Spy Mod, Rear Light Seals, 5000K HID Kit, Navall 3 DD, Blue LED Conversion, Custom badges, Union badges, Flip key. Working on more! [SIGPIC][/SIGPIC]

3rd August 2015, 21:44	#175
karolj Newbie rover 75 Join Date: Jul 2013 Location: Lublin Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	Hi! My 75 does the same. But... yesterday I've replaced my fuel filter and guess what? This weird whining noise just dissapeared. No matter if engine is cold or warm - there is just no whining sound! But after a 50km on new filter the whining sound got back ;/ This sound is only on overrun, so pobably engine is not using any fuel at this moment. My both filters (the previous one and the current one) is made by Knecht. I'll probably change my fuel filter to another brand, maybe MANN. What do you think? What filters do you use?

20th August 2015, 21:59	#179
karolj Newbie rover 75 Join Date: Jul 2013 Location: Lublin Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	So maybe the problem is dying fuel pump under the rear seat?

23rd August 2015, 16:40	#180
Phil th Barrow Gets stuck in " NOW SOLD" :-( Rover 75 Conni Auto SE Join Date: Feb 2011 Location: Stoke Posts: 896 Thanks: 424 Thanked 214 Times in 163 Posts	Maybe dying fuel pump. But mine appears to wines o/s and in front under bonnet on over run. Today it was running very low on fuel and wining . Only said 6 miles range when parked up hill in drive. Drove it a few miles and it said 41 miles range. This is normal. Put 55 litres in it and wine went all together in my 21 mile run around I did after. Jules thinks its HP rail resonance especially with warm diesel in it.