4.2 Intake Runner Fix

[Battle_Tested]

Anyone have feedback on fixing the variable intake runner system on a 4.2? The plastic arms have been replaced on my car with a make due metal rod system. The actuators and pivot arms don't move when the car is running. I plan on attempting to take the system apart to see if it will free up. Is fixing this worth the hassle? If anyone has a diagram of vacuum lines for the system that would be helpful also.

[mithril]

Fixing it is worth it yes, most likely the actuators are seized and need to be replaced. The 3 stage runner effectively changes the volume of the intake manifold at different RPM optimizing and smoothing out the torque curve. As your ECU programmed for this your power, driveablity and fuel economy will all be negatively affected if the system is not working properly.

This is a good howto for fixing seized or sluggish actuators: http://forums.quattroworld.com/a8/msgs/44689.phtml

[A6C5V842]

It is more than worth the hassle. It's essential if you want your engine to perform anything like how it's supposed to.

My old one was a total bastard and never worked quite right.

This one was totally rebuilt and modded for smoother and more efficient operation. There is no comparison. It's like a grown up's B6 S4 when it's running right.

[S6XTC]

Thoughts on best way to test the actuator(s)??

[Battle_Tested]

When the car is off is the intake manifold in a long or short runner state? Im trying to sort out my intake runners on my car now. Since the 6speed swap the system hasn't worked. It make nice power from approx 3k to about 5k but past 5k it feels flat. With the intake runner system not working I was under the impression power loss was on the low end..

[mithril]

Did you flash your ECU with the S6 bin as part of the 6spd swap?

edit: Based on the link I posted in an earlier comment I would say open runner flaps, which equals short intake manifold, are the default when the engine is off. However, if you flashed a euro S6 bin file onto your ECU during the 6MT swap that wasn't modified for the A6 that would explain your lack of torque above 5000. On the A6 4.2 the 3rd runner stage kicks in at 5200 RPM, however the S6 uses a different runner which only has 2 stages so your intake would be going into a configuration which the ECU has no coding for.

[Kaane]

The flappers themselves seize on most of them. Mine were so bad I could barely take them apart. It's a stupid design, plastic arm rides on metal that eventually starts pitting and seizes the arms.

I followed this guide to fix mine.

http://forums.quattroworld.com/a8/msgs/44689.phtml

[BasicA6]

i took the top off my intake and cleaned both ends of those runners. they had gunk on them that would cause them to seize up, once i clean them up the car ran amazing.

[Battle_Tested]

Car has a tune from daz dillinger. A modified s6 euro tune from what I was told. I contacted daz to get details on the tune.

Intake flaps are not working at the moment. I disconnected the vacuum pods while waiting for a replacement. I also need to free up the driver side intake flap as it's sticking some.

Without the system working top end is where I should be losing power?

[Battle_Tested]

Anyone who's intake runner aren't working get it fixed . Had to order new vacuum pods and free up the driver side intake runner. I used the land-rover cruise control pods since it cheaper and easier to find on ebay. Change the system to use one solenoid like 2 stage system and car pulls much nicer to redline..

[rollerton]

Do these manifolds break internally? I've got a car running seemingly pretty well, no more code or misfires- but it's still missing some torque. The manifold moves freely and actuators are working properly, even though the linkage looks like it could fail any minute.
So, no outward signs of signs of problems..but the lack of torque is suspicious.

[Battle_Tested]

Not sure I did not open up my intake manifold. This on a regular 4.2 or a S6?

[8520]

Do these manifolds break internally? I've got a car running seemingly pretty well, no more code or misfires- but it's still missing some torque. The manifold moves freely and actuators are working properly, even though the linkage looks like it could fail any minute.
So, no outward signs of signs of problems..but the lack of torque is suspicious.

I hear you can fix that with a 6 speed swap.