MC Shift, Exhuast stuck on LOUD mode!

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Tucker85

New Member
Messages
9
Hi, my 09 MC Shift has developed an issue with the exhaust sound recently. It appears as though the valves remain open even when not in sport mode. Don't get me wrong, I love the noise but not great when I'm looking to discretely park up on the drive without waking the neighbours.

There is no audible difference in exhaust note when I engage sport mode - hanving researched the forum it seems that some people have experienced the opposite where it is stuck in quiet mode. I've also been underneath to apply some WD40 on the valve/vacuum mechanism which I was able to move around fairly freely anyway so I'm sure this isn't the issue.

Anyone experienced something similar or know a way to fix this so the valves go back to being closed as the default position? No error messages on dash or any other issues with the car that I am aware of!!

Cheers!
Matt
 
CatmanV2

CatmanV2

Member
Messages
48,730
There are two valves. Make sure they both move freely. If they do they you can have an assistant press the sport button in the cabin while you lie under the car and see if they move at all.

If not, my money would be on the solenoid valve having failed, which is a comparatively cheap fix. £35 from Eurospares for the part plus a couple of hours max labour I'd have thought.

C
 
dannywooly

dannywooly

Junior Member
Messages
201
Feel your pain there the sound is immense but not 100% of the time! A 2008 MC Shift i was looking to buy had this same issue, they couldn't free them up as they were stuck, another reason i didn't buy it.
 
conaero

conaero

Forum Owner
Messages
34,626
Sounds like a vacuum issue if no vacuum is present the valves will remain open. Pull the rubber pipe off the valve and start the car in NORMAL and put your finger over the end to see if you have suction.

It could be:

Failed vacuum pipe
Failed vacuum control solenoid
Failed secondary air pump
Vacuum reservoir has a hole in it (highly unlikely)
 
CatmanV2

CatmanV2

Member
Messages
48,730
Conaero said:
Sounds like a vacuum issue if no vacuum is present the valves will remain open. Pull the rubber pipe off the valve and start the car in NORMAL and put your finger over the end to see if you have suction.

It could be:

Failed vacuum pipe
Failed vacuum control solenoid
Failed secondary air pump
Vacuum reservoir has a hole in it (highly unlikely)
Click to expand...

Won't be the air pump. The vacuum is fed by manifold.

C
 
Gp79

Gp79

Member
Messages
1,398
Can you get quality vacuum actuators separately anywhere?

Everywhere i have checked, Euro spares, Meridian etc only lists the whole exhaust back boxes which is silly money.

One of my vacuum actuators is a bit sticky but i can only see cheap Chinese stuff on the web which i am reluctant to fit.

Had it all off earlier in the year and made sure the actual exhaust valves are free so it must be the actuator if there is enough vacuum to operate one of them.
 
CatmanV2

CatmanV2

Member
Messages
48,730
OK the valves *can* stick. But it doesn't mean they *are*

The fuse can blow, the solenoid valve can give up. Any specialist that is asking for (roughly) £1600 to replace the back boxes without proper investigation should be named and shamed.
Short answer there are a number of reasons they won't open.

It is also (as far as I can tell) possible to sort new *valves*. Then it's just a case of cutting the old ones out and welding new ones in.

http://www.ebay.co.uk/itm/Vacuum-Ac...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

£90 for two plus P+P Maybe a couple of hours work?

Naturally not everyone will want to go down this route. However, I will be trying it pretty shortly as I have a rattly valve.

C
 
B

bigbob

Member
Messages
8,965
You might want to check whether the problem is one or both sides. One side of mine sticks in loud mode and only switches back to normal when you stop or drive in town so it's delayed and then speed related. Strange!

The mechanism does work when you manipulate it yourself so I wonder if the vacuum pipe has an issue on that side. Surely it cannot be the solenoid as it will try to switch both sides together?

PS Like Catman's find. I also wonder for me if the valve itself is not being controlled by the lever mechanism correctly?
 
CatmanV2

CatmanV2

Member
Messages
48,730
If it's only one side, then it's either the hose to that side, or that valve / actuator unit for sure.

C
 
B

bigbob

Member
Messages
8,965
CatmanV2 said:
If it's only one side, then it's either the hose to that side, or that valve / actuator unit for sure.

C
Click to expand...
Ta so I need a new hose - easy I guess - or the new valve mechanism you posted welded in. Can you lubricate the valve itself in the exhaust as I've only done the exposed mechanism sliding before?
 
CatmanV2

CatmanV2

Member
Messages
48,730
bigbob said:
Ta so I need a new hose - easy I guess - or the new valve mechanism you posted welded in. Can you lubricate the valve itself in the exhaust as I've only done the exposed mechanism sliding before?
Click to expand...

New hose certainly should be easy. Might be fiddly, but can't be that bad.

As for lubricate the valve I think the answer is 'maybe' When I bought mine the one that now rattles was very stuck (well much more stuck than the other one) I'm really not sure how much of the lube actually got into the mechanism and how much was just brute force. It's probably worth a try, especially if your valve can be moved by hand.

I must admit I'm getting a bit confused over who has what problem! :)
C
 
B

bigbob

Member
Messages
8,965
CatmanV2 said:
New hose certainly should be easy. Might be fiddly, but can't be that bad.

As for lubricate the valve I think the answer is 'maybe' When I bought mine the one that now rattles was very stuck (well much more stuck than the other one) I'm really not sure how much of the lube actually got into the mechanism and how much was just brute force. It's probably worth a try, especially if your valve can be moved by hand.

I must admit I'm getting a bit confused over who has what problem! :)
C
Click to expand...

I think we have a good selection of collective problems.

As as an aside I am in a rental Grand Cherokee at the moment and it's amazing how much what you interact with from the driver's is the same as Ghibli/QP/Levante.
 
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