sport mode - exhaust not working?

[Felonious Crud]

... says the man considering 200 cell sport cats!

Don't get me wrong, Stuart, such frailties would only be short-term. Like at 4am, that kind of thing.

 

[StuartW]

Don't get me wrong, Stuart, such frailties would only be short-term. Like at 4am, that kind of thing.

Yep, fair enough, I forget that not all people have their nearest neighbour half a mile way!

 

[Felonious Crud]

Hmm. Finally investigated this and concluded little. The vacuum pipes work just fine and the valves open and close when I connect and disconnect the vacuum pipe. Trouble is, they don't open when I press sport. I know sport works just fine and everything else happens, but unless I disconnect the hoses I'm stuck in quiet mode. And so it shall stay until after Friday's MOT, but I've asked Lancaster to try and figure out what the issue could be.

Stewart, did you ever find a resolution?

 

[StuartW]

What an odd one Adam & how frustrating too - that quiet mode just won't do
Good luck with the MOT next week, I'm sure she'll breeze through

 

[murph7355]

Something electrical will change the state of the vacuum when the buttons pressed...so a fuse or a connection to a solenoid/valve/whatever will have failed.

 

[Contigo]

I don't know exactly how it works on the GTS but normally there is a vacuum solenoid valve which controls the vacuum delivered to the bypass valves. There is a vacuum line from the engine to the solenoid valve and a vacuum line from the solenoid valve to the bypass valve. The solenoid itself is an electrically actuated magnetic coil that opens and closes the vacuum valve. With the application of an electric signal, the solenoid valve will either open or close to apply vacuum to the bypass valve or vent the bypass valve to atmosphere.

I would hedge my money on the solenoid valve being faulty or stuck open.

 

[Ebenezer]

Out of interest, where does the vacuum come from?
Eb

 

[CatmanV2]

Out of interest, where does the vacuum come from?
Eb

Throttle I *suspect* but....

C

 

[Felonious Crud]

Out of interest, where does the vacuum come from?
Eb

Not sure, Eb. But I need to find out!

 

[Fangio63]

Out of interest, where does the vacuum come from?
Eb

Off the manifold ... surely ..

 

[Felonious Crud]

Apparently Stewart's got pinched somewhere near the front brakes, which suggest that wherever its journey starts it follows quite a meandering route.

 

[Contigo]

Off the manifold ... surely ..

Yep from the engine ie manifold.

 

[Contigo]

Apparently Stewart's got pinched somewhere near the front brakes, which suggest that wherever its journey starts it follows quite a meandering route.

I can't see how a pinch from the engine to the solenoid side could be affecting things in your case.

Before you start the engine on a GTS in non sport mode it Should have valves open simply because there is no vacuum until engine is running. Once running the ECU will want to close the bypass valves which is achieved by a signal being sent to the solenoid valve thus applying a vacuum on the exhaust bypass valve thereby forcing the valves to close. This is where yours fails if I understand correctly. You know there is a vacuum from the solenoid side to the bypass valves but you don't know that the solenoid valve is sending the signal to the bypass valves.

 

[Felonious Crud]

I can't see how a pinch from the engine to the solenoid side could be affecting things in your case.

Before you start the engine on a GTS in non sport mode it Should have valves open simply because there is no vacuum until engine is running. Once running the ECU will want to close the bypass valves which is achieved by a signal being sent to the solenoid valve thus applying a vacuum on the exhaust bypass valve thereby forcing the valves to close. This is where yours fails if I understand correctly. You know there is a vacuum from the solenoid side to the bypass valves but you don't know that the solenoid valve is sending the signal to the bypass valves.

That's exactly how I interpret it, Phil, which is why I'm mystified that Stewart had the same symptoms as me but his issue essentially involved a defective pipe. The way I'd see it, if the pipe for some reason couldn't generate enough suction to pull the valves closed, such as because it had a leak or was kinked, then they'd be open or part-open all the time, not closed all the time.

 

[Felonious Crud]

Lancaster reckon it's the solenoid. They also reckon my car has the wrong exhaust because it should have 2 x twin tailpipes. So I have limited faith.

Initially I decided to go to Grimaldi to get them to deal with it, but having been using the car in Sport with the valves closed I quite like the quiet / loud choice. But I also like it best in Sport, with better gear-changes and sharper handling. So what I want to do is fit a separate valve control thing so I can have the best of both worlds as and when I want.

I'll do some digging and report back but any tips would be welcomed. Will check with Rob at Grimaldi tomorrow.

 

[Contigo]

Lancaster reckon it's the solenoid. They also reckon my car has the wrong exhaust because it should have 2 x twin tailpipes. So I have limited faith.

Initially I decided to go to Grimaldi to get them to deal with it, but having been using the car in Sport with the valves closed I quite like the quiet / loud choice. But I also like it best in Sport, with better gear-changes and sharper handling. So what I want to do is fit a separate valve control thing so I can have the best of both worlds as and when I want.

I'll do some digging and report back but any tips would be welcomed. Will check with Rob at Grimaldi tomorrow.

I said it could be the solenoid but come on are they taking the ****? A GTS MC Shift should have quad pipes?

 

[Felonious Crud]

I said it could be the solenoid but come on are they taking the ****? A GTS MC Shift should have quad pipes?

It's a worry, isn't it. Should I entrust my car to someone who doesn't know what sort of car it is? Er... no.

 

[FF1078]

I had this problem earlier in the year
Mine drove like in sport mode but the exhaust wasn't loud
Turned out to be the relay that controls the solenoid so you should be able to fit a simple switch to power this relay on and off.

 

[Felonious Crud]

I had this problem earlier in the year
Mine drove like in sport mode but the exhaust wasn't loud
Turned out to be the relay that controls the solenoid so you should be able to fit a simple switch to power this relay on and off.

Now that's encouraging... thanks. Where was the relay? I mean, easily accessible, or..?

 

[Contigo]

Or fix/replace the relay.