Exhaust flaps constantly open and lack of power

[m5rosco]

Hi all!

A bit of background info first....

Bought my car in June, as soon as I got it home I wired the exhaust valves open. Recently I had catless downpipes fitted and a remap. Now catless I felt the exhaust was a touch loud, so decided to unwire the flaps so they work as BMW intended, with a view of fitting an aftermarket controller later.

Now, as soon as I start the car, the valves open, even at idle. If I unplug the connector in the left side of the boot (trunk to some of you guys!!) behind the carpet, I hear a little whoosh of air and the valves close. When I plug it back in the valves open straight away.

Alongside this, the car is down on power. With the downpipes fitted, and stage 2 map, it doesn't feel any faster than it did as standard (8.2 sec best 100-200kmh Dragy time).

would I be right in thinking these may be linked?

[technician117]

Maybe the tune has the flaps programmed to be open all the time. The vacuum they operate from comes from the pump that you disconnected the line from. It does not come from the engine. Your power issue is not likely linked to the exhaust flaps.

Have you scanned the DME's for codes?

[Solo_M_Tech]

Originally Posted by m5rosco

Hi all!

A bit of background info first....

Bought my car in June, as soon as I got it home I wired the exhaust valves open. Recently I had catless downpipes fitted and a remap. Now catless I felt the exhaust was a touch loud, so decided to unwire the flaps so they work as BMW intended, with a view of fitting an aftermarket controller later.

Now, as soon as I start the car, the valves open, even at idle. If I unplug the connector in the left side of the boot (trunk to some of you guys!!) behind the carpet, I hear a little whoosh of air and the valves close. When I plug it back in the valves open straight away.

Alongside this, the car is down on power. With the downpipes fitted, and stage 2 map, it doesn't feel any faster than it did as standard (8.2 sec best 100-200kmh Dragy time).

would I be right in thinking these may be linked?

1. The valves will be open for the first 30-60 seconds of start up. That's normal. ON some cars you can even hear the clink sound as they close following the cold start cycle.

2. your power issue could be from a multitude of things from boost leaks to failing turbos to a leaking vacuum line or failing boost solenoid etc. Do smoke test on the car, both boost side and on the vacuum lines coming from the vacuum pump.

3. Post some codes please.

4. My 2014 M5 with factory downpipes and a flash tune made more wheel HP than a colleagues M5 ( catless downpipes DME tunings tune, Intakes and full exhaust) and it came down to a pair of failing turbos.

[m5rosco]

Originally Posted by technician117

Maybe the tune has the flaps programmed to be open all the time. The vacuum they operate from comes from the pump that you disconnected the line from. It does not come from the engine. Your power issue is not likely linked to the exhaust flaps.

Have you scanned the DME's for codes?

Thanks for the reply. There are no error codes present.

[m5rosco]

Originally Posted by Solo_M_Tech

1. The valves will be open for the first 30-60 seconds of start up. That's normal. ON some cars you can even hear the clink sound as they close following the cold start cycle.

2. your power issue could be from a multitude of things from boost leaks to failing turbos to a leaking vacuum line or failing boost solenoid etc. Do smoke test on the car, both boost side and on the vacuum lines coming from the vacuum pump.

3. Post some codes please.

4. My 2014 M5 with factory downpipes and a flash tune made more wheel HP than a colleagues M5 ( catless downpipes DME tunings tune, Intakes and full exhaust) and it came down to a pair of failing turbos.

Thanks for the reply. There are no codes. And the flaps are open even once up to temp.

[m5rosco]

Car is a 2016 model, with 28,000 miles on the clock. I would like to hope the turbos are ok.

[Solo_M_Tech]

Originally Posted by m5rosco

Car is a 2016 model, with 28,000 miles on the clock. I would like to hope the turbos are ok.

Put the car on a dyno. See what the WHP is. That will tell you if your tune is being applied correctly. I've seen a professional tuner load the stock file back into a car by accident and couldn't figure out why the car didn't make more power... to say it was hilarious is an understatement.

[thxbuff2001]

Mine is always open and I dont experience any hp loss.

[m5rosco]

UPDATE!!!!!

Issue diagnosed!

One of the wastegate actuators isn't holding vacuum, therefore, turbo not holding boost as it should. Couldn't find anywhere to supply a new actuator, so a used turbo has been acquired that I will take the actuator from.

[technician117]

Originally Posted by m5rosco

UPDATE!!!!!

Issue diagnosed!

One of the wastegate actuators isn't holding vacuum, therefore, turbo not holding boost as it should. Couldn't find anywhere to supply a new actuator, so a used turbo has been acquired that I will take the actuator from.

Glad you found the issue. Let us know that it has confirmed fixed the problem.

[Sweattdogg]

Glad to hear you found the issue. I have my flaps wired open as many others on the forum do. No loss of power just better sound.