C32 Whistle Noise Help

[sbturbo2]

Hi all, added a eurocharged 65mm sc pulley with a eurocharged tune in January and have been really pleased with the performance gains BUT in the last week or so I have developed a quite loud whistle/wizz whenever I put the throttle down more than 1/2 inch. This noise stays until I let off or just hold the throttle at a minimum. Just been to Stansted and back with no issues and the car is still seems to perform well but it is quite frustrating. I am leaning towards an air leak at the plenum gasket or intake as the noise only appears under load. (doesn't happen when putting the throttle down in neutral). Thinking due to the increased pressure from upgrade....any input would be appreciated. Cheers Simon

 

[AMGeed]

I'd run it back to Eurocharged and ask them to take a look. Internet diagnosis will never beat hands on opinion

 

[Felstmiester]

I'm not at all familiar with the c32. But I've heard of this noise on other cars and in a lot of cases it ends up being the same problem. Try loosening the oil filler cap and see if it makes a difference. The crank case breather could be blocked.

Worth a try.

 

[sbturbo2]

Fitted the sc pulley and downloaded the tune myself but a good idea if needs be. Also fitted new belt and both tensioner pulleys at the same time.

I will check out the breather tmrw too.

 

[sbturbo2]

No joy with the breather unfortunately.

 

[Neil Mackay]

Have you checked all the hose clamps on the intercooler "Y" pipe into the inlet runners!? One may have broken allowing a leak under boost? You'll need to take the intake off the throttle body to check those! Unless you've had the inlet runners off it's unlikely to be a gasket leak there id have thought! It's definitely not the change in charger whine I suppose now it's boosting more!?

Edit - if one of those clamps has broken be careful with the thin metal gasket between the inlet runner and cylinder head (the bit with AMG on it) as they will bend easily! Inlet runner will most likely have to come off to get a new clamp on! Opportunity to check there's no evidence off coolant in the inlet ports at the same time!

 

[sbturbo2]

Hi Neil, I will probably order gaskets tonight and take the tops off. It will give me better access to check the y's etc. The noise is definitely a new one and not the whine from the sc. You can play a tune with the throttle at whatever revs the engine is running by pressing it no more than 5-10mm!

 

[Neil Mackay]

Another thought and I know you said you checked the breathers, but did you check crank case breathers on both sides, plus the one on the passenger side that connects back into the intake pipe just before the throttle body!?

 

[sbturbo2]

Not properly it seems quite restrictive so like you say it maybe worth taking the tops off anyway. Would the breathers make that noise at such low revs?

 

[Neil Mackay]

Not properly it seems quite restrictive so like you say it maybe worth taking the tops off anyway. Would the breathers make that noise at such low revs?

If the connection has come off the black rubber intake pipe after the air filter box you would be pulling in air through a hole about 10mm wide! Under load the charger will amplify that! There is also a vac pipe under that lot which feeds the brake booster which would hiss if it's come off too!!

 

[sbturbo2]

Thanks Neil. That's really helpful. I will focus on these areas first and will let you know what I find

 

[Lyserman]

Have a check of the new pulley bearing.
I had a similar issue a couple of months after fitting my 65mm from EC and the bearing was shot.
Also check the distance between the magnetic clutch and the pulley driven plate (0.2-0.3mm).
They may have had a bad batch of bearings. I replaced it and silence resumed.

Tony

 

[gazz]

I had a similar issue some years back with mine. It had eaten the lower O ring on the number two injector. Very strange, looked like it had been sandblasted and eroded away. I found it with a length of tube held in my ear like a stethoscope. You could hear the hiss of air being sucked in at idle, but only with the tube. Unlikely to be that, but you never know.

 

[sbturbo2]

Quick update.

1./ Pulley bearing appeared a little dry so packed with high temperature lithium grease. Seems quite a bit quieter and there was not a lot of lubrication when I removed the bearing covers. Not sure if that is correct or not??
2./ Removed air boxes, TB and found the breather going to passenger side bank had a 1" split in it. Replaced hose. Checked the state and tightness of the large jubilees and what I could of the connecting hoses. The car ticks over better than it ever has done.

BUT the same noise remains...The Gaskets for the plenum and intake have arrived from Mercedes so I guess the next step will be to take the tops off so I can see if there is a visible leak??

Secondary I thought that I would check the manifold intake pressure through the Euroflash V2 software to see if I was down on intake pressure. The results seem pretty good. I am led to believe standard boost is 14psi while I had readings of up to 18.2psi at 5200 rpm and regular readings of mid 17's psi. This leads to believe I can not have a big leak??

Any thoughts or comments again would be cool

Thanks Simon

 

[Neil Mackay]

Quick update.

1./ Pulley bearing appeared a little dry so packed with high temperature lithium grease. Seems quite a bit quieter and there was not a lot of lubrication when I removed the bearing covers. Not sure if that is correct or not??
2./ Removed air boxes, TB and found the breather going to passenger side bank had a 1" split in it. Replaced hose. Checked the state and tightness of the large jubilees and what I could of the connecting hoses. The car ticks over better than it ever has done.

BUT the same noise remains...The Gaskets for the plenum and intake have arrived from Mercedes so I guess the next step will be to take the tops off so I can see if there is a visible leak??

Secondary I thought that I would check the manifold intake pressure through the Euroflash V2 software to see if I was down on intake pressure. The results seem pretty good. I am led to believe standard boost is 14psi while I had readings of up to 18.2psi at 5200 rpm and regular readings of mid 17's psi. This leads to believe I can not have a big leak??

Any thoughts or comments again would be cool

Thanks Simon

Your boost readings are pretty well bang on I think for the 65mm pulley. Did you have to get Jerry from EC to allow data logging on your Euroflash Software? I read my boost through the OBDII port and get upto 21psi but mines dyno tuned and throws an overboost code all the time! I'm not totally sure how accurate Dash Command is for reading things like that!

 

[sbturbo2]

Never contacted anyone at EC, I presumed it was part of the software? To make it work though I go through the motions of starting an upgrade by selecting the file then go to data logging. It doesn't work unless I do that.

 

[Neil Mackay]

Never contacted anyone at EC, I presumed it was part of the software? To make it work though I go through the motions of starting an upgrade by selecting the file then go to data logging. It doesn't work unless I do that.

Ahhh righto !! I may play around with that at the weekend then ! Sounds to me like there's not actually anything wrong with your car if the boost parameters are about right. Doe the software estimate power?

 

[sbturbo2]

Ahhh righto !! I may play around with that at the weekend then ! Sounds to me like there's not actually anything wrong with your car if the boost parameters are about right. Doe the software estimate power?

Not that I noticed I tend to look at the IAT and PSI only. Also I check out if there are any outstanding or current error codes

 

[french]

I fitted my 65mm pulley & remap in November & I too have the louder whistle noise but no leaks, I just thought its the extra boost...you've made me wonder now ,very pleased, it goes like a stabbed rat .

 

[Neil Mackay]

Not that I noticed I tend to look at the IAT and PSI only. Also I check out if there are any outstanding or current error codes

What sort of IAT's are you getting at full throttle and general driving?