Exhaust open flaps diy from under the hood easy version

I also tried this but do not notice any change. I tested by starting the engine, letting it idle until RPM drops and exhaust note settles down. Then I pulled the hose expecting the exhaust note to change. But it did not, not noticable anyway. Should I hear a clear difference or is that only when you are driving?

 

If there is no noticeable difference in sound then I would suggest your exhaust valves are seized closed or a previous owner has wired them open as there is a marked difference between pipe on and off especially after the initial start up fast idle has stopped
Cheers
Andrew

 

Thanks Andrew! This made me check under the car to see if the solenoids for the exhaust flaps work at all. They do, open when engine off (well, assuming it is open, the rod that comes out of the solenoid is outwards in that position), and when engine on they close (rod in inward position).
Funny thing is that this still happens when I pull the hose from the line and put a plug in the hose. So opening and closing the valves does not when pulling the hose? Added a picture of my car showing that hose with a screw blocking it, that is exactly as it should be right?

 

yep, that’s the correct pipe, ???
Have you checked for a vacuum on the other end ( the part you plugged) when the engine is running?

 

Hi Andrew, yes, I did. When I put my finger on the hose I can feel that there is suction. yes to make sure, the exhaust flaps are being fed by the line to which the hose is connected right, so the one to which the arrow is pointing in the below picture? And when the hose is attached the vacuum you get when starting the engine causes the flaps to close. Unplugging would mean there is no vacuum and therefore flaps should remain open. So how can it be in my case that flaps still open ánd close when I pull that hose off?
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I was thinking, I have a California (2011) with the HELE (High Emotion Low Emission ) option, could that somehow affect the exhaust valve control?

 

Did you remember to also block the part where you disconnected the pipe from and not just the pipe it self?

 

I did yes. Although that should not matter since when there is no vacuum in that line which leads up to the solenoids the flaps are and should remain open. That is at least how I get it.

 

Update - I was planning to remove the vacuum tubes from the solenoids that control the valves at the exhaust but when I started the engine (the hose in the engine bay was still removed) the valves remained open. Engine off and on gave the same result. Did not attach the hose in the engine bay at this point to see what happened then, was happy that it worked for now. Looking at a schematic overview of the air system (see pic) it shows a so called vacuum accumulator tank at the rear, above the right exhaust. A solenoid is behind it controlling the vacuum to the exhaust valves. Could it be that this accumulator holds enough vacuum, even when the vacuum hose in the engine bay is disconnected, to operate the valves a few times before vacuum has dropped too much?
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When I clamped mine, yes I clamped it I didn’t remove it and plug it, it wasn’t until a couple days later that the valves were open full time. Not sure what the reason for that could possibly be I can’t think of the mechanism of action for it but that is what happened…

 

Can anybody tell me what size the vacuum lines are? 6mm or 8mm?

 

I did this in Oct 2023 on my 2012 California (non 30) and it worked great! it has more of a grumble and pop sound at lower RPMs.

it took less than five minutes and I used rubber vacuum caps for a professional look

 

worked a dream for me thankyou