Resonance flap explained?
Thread Starter
Three Wheelin'
Joined: Oct 2011
Posts: 1,334
Likes: 4
From: Boston Burbs.
Resonance flap explained?
Not much about the resonance flap out there. It was mentioned here that it could be the cause of my frustrating stumble at wot between 5500-6000 rpm. Can anybody fill me in more?
Nordschleife Master
Joined: Jul 2007
Posts: 5,613
Likes: 52
From: DFW, TX
I don't think it should cause a stumble at the RPM range you quoted, but if it is not functioning, it will definitely cause less power at the top side of the rev range.
See the graph posted in this thread.
https://rennlist.com/forums/964-foru...eave-open.html
See the graph posted in this thread.
https://rennlist.com/forums/964-foru...eave-open.html
Thread Starter
Three Wheelin'
Joined: Oct 2011
Posts: 1,334
Likes: 4
From: Boston Burbs.
Wondering if this is why the coupe feels so much faster off the line then the targa? Coupe appears to have same flywheel as targa I can see through the tranny hole, so ruled out LWF. The targa has this dead spot at 5300-5500? Rpm 3/4 of the time when I let it rip. Then it is like a turbo to redline. Just trying to figure out what this is. Motor runs and starts and idles otherwise perfect. Always has for 3+yrs since I have owned it. I used to think it was coil related but tried 3 sets in the past. I kinda just lived with the annoyance. Now want to know.
Instructor
Joined: Jul 2010
Posts: 239
Likes: 2
From: Jakarta, Indonesia
You need to remove the throttle body. I advice everyone to clean the TB & check if the resonance flap is stuck to its wall, like mine did. Here is my thread
https://rennlist.com/forums/964-foru...eck-yours.html
https://rennlist.com/forums/964-foru...eck-yours.html
Thread Starter
Three Wheelin'
Joined: Oct 2011
Posts: 1,334
Likes: 4
From: Boston Burbs.
You need to remove the throttle body. I advice everyone to clean the TB & check if the resonance flap is stuck to its wall, like mine did. Here is my thread https://rennlist.com/forums/964-foru...eck-yours.html
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Rennlist Member
Joined: Jan 2007
Posts: 2,388
Likes: 17
From: Vancouver Island, BC , Canada
To start, do you hear a CLICK in the engine compartment, when you turn the key to the on position ?? If you do that the dme cycling the flap. If not, make sure there is vacuum to the solenoid switch. There is a vacuum line that run from the solenoid to the vacuum canister on the back side of the air filter housing.
Check these things out first, then report back with the results.
Check these things out first, then report back with the results.
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Rennlist Member
Joined: Jan 2007
Posts: 2,388
Likes: 17
From: Vancouver Island, BC , Canada
If you hear that click in the engine compartment, then you know the RF is operational, I.e. Not stock.
Next you should check to see if the cam that activates the wot micro switch is actually doing it's job. Manually open the throttle and look at the cam, it should activate the switch at 3/4 - 7/8 throttle opening. You hear a click from the switch when it's activated.
Next, disconnect the plug at the solenoid switch, and then with a 12v battery or even just a 9v, check if that is working. The switch should open the vacuum line that activates the RF pod, in other words, you should be able to move the RF by applying power to the solenoid contacts.
Check this and report back.
PS. I borrow this picture from Jason, hope he doesn't mind. You can see the solenoid switch, the vacuum line and where it hooks into the pod, that in turn move the RF. Right above the arrow on the inside of the vacuum line is the wot micro switch and cam.
Next you should check to see if the cam that activates the wot micro switch is actually doing it's job. Manually open the throttle and look at the cam, it should activate the switch at 3/4 - 7/8 throttle opening. You hear a click from the switch when it's activated.
Next, disconnect the plug at the solenoid switch, and then with a 12v battery or even just a 9v, check if that is working. The switch should open the vacuum line that activates the RF pod, in other words, you should be able to move the RF by applying power to the solenoid contacts.
Check this and report back.
PS. I borrow this picture from Jason, hope he doesn't mind. You can see the solenoid switch, the vacuum line and where it hooks into the pod, that in turn move the RF. Right above the arrow on the inside of the vacuum line is the wot micro switch and cam.