Re: High idle and fan.

[16v Jason <jason@scirocco.org>]

Brian,
         Well, the good news is that the problem doesn't sound all that 
bad.  Here's the deal -- when the engine thinks the A/C is on, it adds some 
extra gas at idle, and then some more when off idle.  Case in point -- My 
car idles at 900rpm regardless of A/C being on or off.  When my compressor 
was dead (i.e. not engaging), and I had the switch set to A/C ON, the car 
would idle at 1000rpm instead of 900.  Then, if I applied the slightest 
pressure to the gas pedal (i.e. tripping the microswitch), idle would be 
between 1600 and 1800.

         So, from the sounds of it, two things are happening to your car:

1)  Your idle switch is a bit sticky...  soak it with WD-40.
2)  The compressor's not always on when your engine thinks it is.  That 
coupled with the fact that the A/C  sometimes not blowing cold confirms 
that suspicion...

Therefore, I would check the pressure switch connections on your A/C lines 
(as the compressor will not engage unless sufficient pressure is in the 
lines), and the electrical connections to the compressor.  If you rule out 
both of those, check your refrigerant pressures and they'll probably be low 
(although that would be strange cause you said it's cold).

Good luck and keep us posted!
Jason




At 03:28 PM 7/5/2000 , Captnbr@aol.com wrote:
>Has anyone been able to figure out what causes the high Idle when the A/C is
>turned on besides the idle switch on the throttle body.  I feel my idle
>switch is working because when the A/c is off it Idles fine at 900 rpm.  I
>put the a/c on and it idles fine at 1000rpm.  but sometimes I come to a light
>and it will then idle at 1800 rpm and I have to cycle the a/c off then on the
>get the idle to drop or I have to turn the steering wheel back and forth that
>works too sometimes, thats why i think it is something other than the idle
>switch , any ideas?
>
>This might be related to above.  Sometimes my A/c is not that cold. It does
>have a full freon charge and when it works it is ice cold.  It seems to cut
>off on hard acceleration sometimes.  I have narrowed it down to the radiator
>fan.  Seems like when the fan is on it is ice cold and when the fan is off it
>is not cold.  And its seems that when the radiator fan is on the idle is fine
>but when the idle is high the fan will not be on and the A/c will not be that
>cold. hmmmmmm, Oh and the coolant temp is normal there is no overheating
>going on it just with the A/C.  Thanks for any ideas. peace
>
>Brian 86 16v
>http://hometown.aol.com/captnbr/myhomepage/auto.html
>
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----------
1987 Scirocco 16v
1988 Mercedes 190E Sport Euro


http://members.aol.com/rocco16v 

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