[Shotimes] High idle problems

[Dave Kegel]

Gotta be a vacuum leak.

Dave

-----Original Message-----
From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
On Behalf Of Zach Leahy
Sent: Tuesday, October 11, 2005 11:15 AM
To: SHOtimes
Subject: Re: [Shotimes] High idle problems


Don,
 I am battling something similar on my 93 right now. I had the intake apart
and sent the runners off to Extrude Hone, and now have an idle problem with
the intake back together.  So here is my symptoms and so far my actions.  I
get a stopped neutral idle of about 1750-2k rpm, and it does not want to com
back down when you blip the throttle ver quickly. It was even higher than
that in the 3k range.  Problem #1 I had was that I installed the little
warmup loop (which is disconnected on my car now from the coolant) that is
at the IAB backwards. When you have it off and are not putting on hoses you
can make this mistake easily. The result was a vacuum leak and a partial
contributor to my high idle.  Fixing that has brought my idle down from 3000
to about 2000. If I back out the throttle stop screw I can get it to drop
another 250-500 rpm. I know that's not the correct way to adjust the idle,
but it allows me to verify that the air is either A) coming around the
throttle plate through the IAB or B) entering the intake unmetered after the
throttle plate.  I unplugged the IAB with the motor running, guess what, no
change at all. my theory is that my IAB is stuck in the open position. I
sprayed it out with some carb cleaner when I had the manifold out, as I did
all the other components, and found it was not dirty at all as I expected.
Interesting to note, I have not plugged in the Tweecer to see wha the MAF
reading is (telling me whether the air is coming throug the MAF or not -
seems like it is as there is a lot of "sucking" noise through it) but the
PLX WBO2 is telling me the mix is pretty much 14.7 Either the O2s corrected
for the vacuum leak and upped the fuel or ther iar is realling going through
the MAF and is metered correctly and is getting the proper fuel delivery. I
support the latter theory which seems to indicate a stuck open IAB. I'm just
lazy and cheap and don't wanna replace it.  I would say on the ATX that is
not idling correctly to look for a vacuum leak to begin with, listen for it
in different places. Try the propane torch trick if you need to try and
locate it. Look for a missed vacuum line on the intake.  Z


On 10/11/05, Donald Mallinson <dmall@mwonline.net> wrote:
>
> Got a note from a member that is having problems with their 95 ATX SHO 
> with high idle.
>
> It is at 1000 rpm at a stop in gear, and 1500-1700 in neutral.
>
> On light acceleration, the car gets to 35 mph at about 2000 rpm and 
> doesn't want to shift to second gear.
>
> The owner recently replaced the IAC valve, TP sensor, VSS sensor, 
> upper manifold gasket,
>
> Oxygen sensors, Cam Poisition sensor, and ECT sensor. He tried to find 
> trouble codes but their are none in the computer.
>
> Any ideas?
>
> Don Mallinson
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> Shotimes mailing list
> Shotimes@autox.team.net http://www.team.net/mailman/listinfo/shotimes
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