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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by bleachii View Post
Thanks for the responses guys. The windings would make more sense from what I read to explain such a sudden drop in the RPMs.

The author explains how the WUR adjusts pressure based on the temps of the engine (cold vs warmed up). The initial requirements of a cold engine are different than the engine once it warms up. Also, there can be a good 10 min or more before the engine is warm enough for the WUR to make the necessary adjustments (for this reason the WUR is very close or on the engine block per the book). I have no idea where it is located yet on my car. I'm in the Sierra's reading so no access to the car.

The electric winding is therefore engineered to force the WUR to adjust pressure after the cold start but before the engine is completely warm. Basically it tricks the WUR into thinking the engine is warm earlier than it naturally happens.
You've got it!

The AAR (sometimes also referred to as AAV....but it truley is a Regulator and not just an on/off Valve) will wear with age and may cause different warmup characteristics; i.e., may result in a higher, longer sustained high idle, or conversely the opposite of that. The fact that you have high idle when cold and that it drops back down within just a few minutes says everything is probably working as it should.
Also tuck into the back of your mind that both the WUR and the AAR have internal heating elements which receive their power through the rear fuel pump relay.
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 04-05-2013, 09:56 AM
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