Question for owner with a v6 base with active exhaust

K

Kdes

New member
Reading these and other forums I’m not sure my active exhaust is functioning 100%.

Firstly my car is pre-owned so I don’t know it’s history and I suspect it’s had the Jaguar modification to the vacuum to convert it to to the engine vaccum rather than the pump. It appears that early cars had an electronic pump to provide the vaccum and later cars have the vaccum from the engine. Some cars (and i suspectmine) have th epump removed and the pipes re-route dto the endgine to deal witha noise problem.

Secondly there seems to be a lot of misinformation on the web as to how the active exhause operates and the various combinations of with and without switches. to he 100% clear it ispossible to have an active exhaust without the switch. Whilst there is no manual intervention It is OPened/closed by ECU/engine load and ON in Dynamic mode.

This is compounded by he fact that the active exhaust operates "back to front" from a logic point of view in that its default Mechanical position is OPEN with it being held closed by a vaccum. (This partly explains the roar on start up). I have done a lot or research and have some Jaguar documentation which partly explains the operation but need a real world comparrison.

What I can say is i do have both quiet and loud but its not as quiet as I think it should be and not as loud as some on here and other forums describe. The obvious conclusion is a valve is sticking but i have manipulated them by hand and they both seem to have full travel, The fault I suspect I have is that there is an inadequate vaccum (sometimes but not always) and therefore the exhaust is open more or earlier than it should be. This may be a fault or a direct result of the vaccum conversion.

I also have an unconnected wire hanging down behind the rear wheel which is why i think the original Vaccum pummp was removed or disconnected.

I have booked the car into my local jag dealer but wanted to be as informed as possible before the visit.

So is there anyone on here with an 2015/2016 V6 340hp WITH the active exhaust WITHOUT the interior switch that would be able to answer a few questions either here in the forum or by PM ?

Thanks
Kev
 
I can’t help with the above but you CAN have Active Exhaust (ie dynamic mode) where valves are opened according to throttle/revs, but that’s not the same as Switchable Active Exhaust that opens the valves via press of a button at any given time (fully open on earlier F Types).

As mentioned on another thread, jag DID make a change (around 2015 I think) so that say upon idle or low revs pressing the exhaust button would open them part way and then combined with dynamic mode selected the exhaust is open FULLY at all times for the user.

If you DONT have switchable active exhaust then you would have to rely on the revs being appropriate built up and dynamic mode being selected I presume.
 
I have the button, but all this does is override the ordinary non switchable operation. Just been out for a play with it.

So, ignoring the button. In normal mode, the active exhaust is open on startup and then closes. The exhaust will then open/close in normal mode around 4000 rpm. Switching to dynamic opens the exhaust all of the time. The difference is noticeable with 2000+ rpm and the engine pulling, less so when coasting and not under acceleration.

The button opens/closes the exhaust i.e. it will open it in normal mode and can close it to override the 4000+ opening or dynamic opening. I couldn't hear any difference between 'normal mode button open' and 'dynamic open' other than dynamic creating pops and crackles on overrrun.
 
Thanks for the responses to my post. I think my valves are partially opening at 2000rpm. This initially causes a quite unpleasant drone (typically at motorway cruising speed) until the revs increase a bit.

Also other than a few more pops at around 4000rpm “normal” and “dynamic” both have a similar volume level. My issue isn’t so much the it isn’t loud enough, it’s plenty loud enough at medium to high revs :D the issue is that it’s also loud at lower revs which from reading/research I don’t think it should be. My guess is insufficient vacuum to fully close the valve or maybe it’s just a sticky or stiff valve.

I had another poke around underneath today and there’s is a small hole in the weld where the pipe meets the back box and some soot staining. It’s not very large and I don’t think it’s the source of additional noise but doesn’t bode well.

Dealer taking a look later this week so will see what they say.

For info here’s one of the jaguar docs describing the active system. (2013/4). Early models have his pump. Later models don’t. As I said in my first post I think my pump was removed as part of a previous ‘fix’ or update TSB.
https://www.dropbox.com/s/szc3vze5olrcol9/active_exhaust.pdf?dl=0

Kev
 
I appreciate I’m may be answering my own questions, it sometimes it helps to think out loud.....and this may be useful to others.

Here’s the info on the mod I suspect my car has -
https://jlr.oemdtc.com/74/active-exhaust-vacuum-pump-noisy-2014-2016-jaguar-f-type

The wire I’ve got hanging down is possibly the disconnected one shown in the pic of step 5. So it may be related to my issue.

I think the pump was permanently deleted from the factory build at some point but don’t know when.

Kev
 
mickjaguar said:
I have the button, but all this does is override the ordinary non switchable operation. Just been out for a play with it.

So, ignoring the button. In normal mode, the active exhaust is open on startup and then closes. The exhaust will then open/close in normal mode around 4000 rpm. Switching to dynamic opens the exhaust all of the time. The difference is noticeable with 2000+ rpm and the engine pulling, less so when coasting and not under acceleration.

The button opens/closes the exhaust i.e. it will open it in normal mode and can close it to override the 4000+ opening or dynamic opening. I couldn't hear any difference between 'normal mode button open' and 'dynamic open' other than dynamic creating pops and crackles on overrrun.
Click to expand...

I don’t have the button but I do have the active exhaust. My owner’s manual says the valves automatically open when dynamic mode is selected. In my car, the engine sound is slightly louder, lower pitched, pops and crackles 4000+ when in dynamic mode. I use the flappy paddles because the gears change up before hitting 4000.

I almost think the button is useful if you’re in dynamic mode and want to close the valves.
 
Quick update

Loose wire behind rear arch was re-connected and exhaust now sounds correct both on and off load. Wire connects to pump or solenoid (not sure which) I suspect it’s disconnection has the same effect as “pulling the fuse” that some do to keep valve open - hence the noise all the time.

7ec380637faa254f7a9f67e9a895155a.png
 
Kdes said:
Quick update

Loose wire behind rear arch was re-connected and exhaust now sounds correct both on and off load. Wire connects to pump or solenoid (not sure which) I suspect it’s disconnection has the same effect as “pulling the fuse” that some do to keep valve open - hence the noise all the time.

7ec380637faa254f7a9f67e9a895155a.png
Click to expand...

yes ... that would be the connector for the Vacuum solenoid valve :)
 
I have a 2015 base model and it does have the active exhaust which Jaguar confirmed to me. It does not have the switch to open the valves. I decided I wanted this option but Jaguar will not retro fit the switch. I looked around on the net and found a company called CCCharger who supply a fuse box modification and remote control that allows you to open the valves. I am really pleased with it. You can find them at CCCharger.co.uk.
 
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