View Single Post
mark houghton mark houghton is offline
Registered User
mark houghton's Avatar
Join Date: Jul 2008
Location: Central Washington State
Posts: 3,860
Sometimes I wonder if we shouldn't have a 'sticky' on AAR's, since they come up so often. The cheap fix is to put something inside the hose to reduce the amount of air getting in. Or, a small C-clamp or some such device to clamp the hose closed to the degree you want it. Pretty Fred Flintstone, I admit.

The simple diagnostic when seeing super high cold idle is to completely pinch closed the hose leading to the AAR. Your idle should drop down well below 900. If it doesn't, then it aint your AAR causing the high idle.

However, in your instance even though your idle is too high when cold (3200), I find it interesting that the idle eventually drops back to normal when warm (I'm talking 950). That range isn't normal. With that high of a cold idle, it would indicate that the AAR is too far open in its normal range of movement, and conversely won't be closed as much as it should be when fully warmed....which should result in a too-high warm idle as well.

Pull off the hose to goes to it and scope out how far it's open (shine a flashlight into the bore), both when hot and when cold. There should some....but very little....of an opening when she's warm. You can reach inside with a pencil or suitable instrument and forcibly rotate the disc to expose the opening - to get an idea of how much is available. Also check the hose leading from the AAR to the manifold to make sure it isn't a source of unmetered air leaking in.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 06-06-2013, 06:43 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)