Vis!

[mattie007]

I maybe getting a 180 in a few weeks but it has a VIS issue.
I understand that if its broken there will be no kick at 3k rpm.
However, if its the plenum thats broken, willl there still be a kick at 3k rpm?
Im not sure how I can tell whats broken as apparently both rattle?

are you sure the plenum is rattling? it may just be the purge valve at the throttle body it makes a rattling sound and is nothing to worry about, if the plenum is goosed i would imagine the symptoms will be the same as faulty vis motors

[mattie007]

Apparently its the balance vis motor thats gone. Just want to know how I can tell if it the VIS or the plenum.
I no about the purge valve as its very loud on my 120!

Also, whats the difference between the power vis motor and the balance vis motor?

[Jay-ZS+]

See if you can nick a decent Vis for the day and try it out with that fitted. Only a 2 min job to swap them over.

Originally Posted by mattie007

Apparently its the balance vis motor thats gone. Just want to know how I can tell if it the VIS or the plenum.
I no about the purge valve as its very loud on my 120!

Also, whats the difference between the power vis motor and the balance vis motor?

the difference between the two i don't know but i think to test the plenum you should remove the vis motors and check the action of the arms in the plenum it should be smooth with no sideways movement and no sticking.

[mattie007]

Sounds like a plan.
Is there anyone who lives near Romford, Essex who cold come and look at it with me?

[Dan1971]

I don't live too far away .... Can give a second opinion mate, but I'm no mechanical expert. I might be able to get hold of a vis tester though which will help.

Got a link to the one you're looking at ... pm it if you're keeping it quiet. Also, how do you know already that it has an issue ... ?

[stamford]

To check the plenum remove the power vis (top unit) and check the atuator arm for excessive movement. It should be smooth and a linear action. If it rocks and is real sloppy then suspect the arm is worn and not locating all 6 off butterflies. If the plenum is broken then there will be no kick as the vis maybe working but not opening the butterflies, besides it will sounds like a bucket of bolts when running, this is the airflow slapping the butterflies against the orifice and bouncing.

The balance vis is a pig to remove unless you have a modifed tool to remove the screw nearest to the reservoir. All this operates is a butterfly, these can stick a bit causing the motor to fail. Might just need a light deburr to free the butterfly up a bit.

[Maxfly]

The balance vis is a bit more awkward but all you need is a set of small mole grips as there is enough of the screw head sits out to get a grip of!! Took me 5 mins using this method to remove the unit. An no damage to the screw head as long as you don't hash it Think i put up a guide somewhere, will have a hunt

Here it is
http://www.themgzs.co.uk/vb/showthread.php?t=7314

[stamford]

I cut a screwdriver bit in half, ground it down to keep it as short as possible and superglued it to a 1/4" spanner, did the trick.