Forums - View Single Post - What could be the cause of this odd rev behaviour? (video included)
View Single Post
post #11 of (permalink) Old 19-04-2017, 18:21
Registered User
Join Date: Jul 2012
Location: Hunstanton
Car: MGF
Posts: 3,339
two things happen with the iacv...

1. the rubber hose is old and doesnt seal properly sometimes but not always, so the air going in at idle isnt settled... its constantly changing..

2, that pipe sits on an aluminium pipe and it gets coated in the dreaded ally white dust.. that dust gets into the iacv mechanism... and then reacts with anything already in it... its an electrochemical reaction, you cant stop it.. rain water.. puddles splashes, react with the ally pipe.. and then that crap reacts with anything in the iacv.. eventually that crap dust stops the iacv moving properly... one can hear that sometimes with the engine cover off... clicking noises as it jumps instead of resetting smoothly..

the result is the iacv mechanism gets covered in dust and dont work properly... that and age, mean it dont do what its supposed to do..

one can try cleaning it.. as suggested.. brake pad degreaser... pipe freezer spray... something with a totally evaporating action without water in it.. not anything oil based like wd40... dust will quickly stick to any oil residue left inside...

ptfe based cleaners might help... the ptfe aids slippery surfaces... and that is what one wants in nearly all the iacv... to help it seat properly... and ptfe is pretty non reactive as far as the engine is concerned..

the only other solution is buy a new one...
Incony is offline  
For the best viewing experience please update your browser to Google Chrome