Question on Q45 Exhaust Control Valve

[BlackRB]

Hey guys, I have an 2003 Q45 that i wanted to put the Quad Exhaust system on it, but run over some issue. It the Exhaust Control Valve. Can anyone tell me if I can eliminate the ECV on this Q. And does its affect anything to the emission system or its perfomance? I have the pictures of it in RED circle. Any advice will be greatly appreciated. Thanks

[BlackRB]

Come on yall, need some help here

[Q451990]

I hate to say it, but we don't have a huge amount of F50 experience here. Probably a function of the low sales figures.

I think I would try unplugging the control unit in the trunk a couple of days with your current exhaust system and see if it throws a code. The controller is controled by the ECU, but I don't see a DTC for it not working correctly, so I don't know if it actually gets feedback from the controller.

Heath

[BlackRB]

Well, i guess i might try it whenever i have the scanner to clear the code. Thanks

[Q451990]

From reading the service manual, it looks like the exhaust control valve control unit only monitors the throttle position and rpms from the ECU. I don't see anything in the DTC code index that suggests that the function of the valve is actually monitored. I even looked through the troubleshooting for the O2 sensors, and I don't see any possible cause for a fault being an inoperative exhaust control valve.

So I feel fairly confident that you can delete it - but I think the only way you'll know for sure is to try it. Since you posted pictures, I assume you have access to the service manual? If not, you can download it at www.nicoclub.com/FSM/

Please keep us posted on this... I think I saw a similar question on the M forum or G forum... can't remember which.

Heath

[BlackRB]

So the Muffler Control Unit is control the Actuator to close and open the ECV. If we delete the ECV we have to disconnected from the Actuator OR disconnect both from the Muffler Control Unit. Then, check engine light might turn ON or code with be shown. Right?

[Q451990]

I relaly don't know if a code could be thrown... from the little bit of information I see in the FSM, it looks like there's no feedback to the ECU to tell if if the valve is actually working. I think the only way we'll know is to disconnect it and see...

Heath

[BlackRB]

I'm just afraid when i disconnect the Muffer Control Unit then the Valve will be close at all time. That can ristrict the air flow from the exhaust system and could cause HIGH back pressure. That is not good for the motor.

[Q451990]

That's true... I was thinking just to try it for a few minutes at low speeds. Or maybe you could hold it open at all times manually during the test using vice grips or a cable tie.

Heath

[BlackRB]

I guess i will do that this weeken. I will post up the result. thanks Heath

[xerexabante]

I have mine wired open for about 2 years now. Does it make a difference I do not know, it sure feels that it breathes more you can hear more of a grunt when start up and that low rumble at idle .
Just disconnect cable from valve let it hang and get a wire clothes hanger wrap it on open. There will be no MIL codes that will appear.

[SteveTheTech]

You can indeed remove it, the valve was to reduce backpressure under high loads. Higher backpressure was used when they first removed the egr and started to play with valve timing. The system is very simple. There is an output from the ecm to the exhaust valve control unit but it does not appear that that is a detectable line.

I don't have any numbers on the performance from either removing or defeating but I have a feeling the Q forum has something somewhere about this. I really wonder just how much it works, and I always have.

[BlackRB]

Thanks alot for the input guys. That is great information, keep posting it. BTW i think that the valve is there just for air flow purpose just like STEVE said, and for noise reduction just like XEREX said too. BUT THE QUESTION IS how can we disconnect the Control UNIT without the ECU code showing? If we can do that than we can purchase the catback system on the M45 and put it in our Q (I have look on Ebay on the M45 Megan catback and it does look like it going to fit with some modification needed).

[xerexabante]

Well, leave the actuator alone(plugged harnnes) and disconnect the cable to valve. You should be good to go.

[Q451990]

From what I see the muffler control unit doesn't communicate back to the ECU, so it shouldn't be able to throw a code no matter what you do.

Heath

[BlackRB]

well i will give it a shoot whenever i have time and will post this up