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RE: daily update
this is really strange, because the behavior i observed
today is exactly as phil describes it here. hmmm, grounds
for further research, for sure.
On Tue, 1 Dec 1998, Buchholz, Steven wrote:
:|> > also, noticed a new unusual behavior. the car
:|> > seems to not want to let go of the idle speed
:|> > when i clutch in - between gears or coming to
:|> > a stop. it takes several seconds for the revs
:|> > to drop down to idle speed once i stop. the drop
:|> > is a slow, smooth decline. i am going to check
:|> > the throttle linkage stuff, but i thought there
:|> > might be a good btdt from y'all.
:|> You fixed something. This is what it's supposed to do - or at least,
:|> it's what the ur-quattro ISV controller is supposed to do, and I think
:|> it's the same part.
:|> Idle is 800 rpm at rest - optimised for low vibration. It's raised if
:|> the battery voltage is low or the a/c is on. The ISV will _not_ allow
:|> idle to drop below 2000 rpm if the vehicle is moving - it assumes you
:|> might need the power steering or the brake accumulator refreshing.
:|> If you knock an ur-quattro MB (equivalent to the MC engine) out of gear
:|> and coast gently to a stop, the idle drops in specific stages and
:|> finally drops to 800 rpm some seconds after the car comes to a halt.
:|... for better or worse, Rocky lives here in the good ol' USofA ... which
:|means that unless his car was modified by a P.O. it is equipped with the WX
:|motor ... which might map somewhat to the WR with which you may be familiar
:|... the only sort of idle speed control that the WX motor has is a timing
:|advance that the ECU kicks in if the idle speed drops too low. Cold engine
:|throttle plate bypass is controlled by an Auxiliary Air Regulator (AAR)
:|valve ... it has no ISV.
:|I think that Rocky has pretty much nailed the possibilities ... something
:|may be sticking in the throttle linkage (don't discount the cruise control
:|actuator). Newer turbos such as the later MC engines had a dashpot on the
:|throttle body which prevents the throttle plate from closing abruptly, but
:|the WX doesn't have this mechanism either. In trying to think about other
:|oddball faults that might cause the idle to drop slowly ... perhaps the high
:|vacuum condition in the intake manifold is causing one of the throttle valve
:|bypass valves (AAR, valve that provides bypass when the A/C is on, etc) to
:|be drawn open and bypassing the throttle body ...
:|San Jose, CA (USA)
two strokes are faster than four!
this message was composed using the vi editor.
'83 ur-q - yamaha rz350 - suzuki ts250 - chaotic good