AC/Idle issue

[Rat407]

I know this is probably an easy fix but I'm just making sure on this. I finally got the AC fixed on my 91 ECO jetta. Now the issue is when the AC is on the idle drops down so low that it shakes the car apart.  If I turn the idle up to compensate for the AC then when the AC isn't on I have a super fast idle. Is there anyway around this or is that just the way it is going to be?  Also I know where the idle adjustment is located on the pump. Is it possible to just adjust the throttle lever stop up some instead of cranking up the actual idle? Thanks.

[95gltd]

i'd like to her the answer too, my 95 golf TD has the same issue. A/C on max with the fans going idle drops down to 800 rpm. On Gassers the idle increases automatically when the compressor comes on. You'd think a diesel would do the same.

[jtanguay]

well our mechanical diesels dont have electric fuel injection, or timing.  so a computer cannot compensate for the added load.  I too am surprised, but not worried about a little shaking.  For added fuel economy I'd suggest turning it off at idle anyways.  It is the drag from the compressor when accelerating that uses the most fuel.

I'd say switch to that HC-12 stuff (basically propane).  it uses less pressure so that means the a/c compressor does not work as hard and thus, less overall shaking.  Anyone who says putting propane in your a/c system is dangerous is only right if your a/c system has a nasty leak.  We're not talking about a barbecue propane cylinder here!!! and with auto ignition temperatures of around 3000F I'm pretty sure, no wait positive, that it won't be igniting under pressure inside the closed system.

and as for an accident.. well.. how much damage will such a small amount of propane do? if indeed it starts leaking, and a flame just happens to be there to ignite it, maybe it will blow the hood off the car?

work case scenario, a smoker gets into a huge accident, the evaporator leaks into the cab... ignites... but hey, smoking kills right???

Just going off on a tangent there!  I'm really pro HC-12 for the environment!!!

Edit: is there some sort of idle boost relay on motors with a/c?  because I hear my motor's rpm's drop when a/c is on, but on the gauge it barely moves 50 rpm.

[Darkness_is_spreading]

It's like climbing a hill, because the pump engages like a clutch, it will lug on your system.  Just rev up the motor at idle, or shut off the AC at  idle.

[nkb]

both of my passats have a/c and they idle up with it on. goes from 1000rpm to like 1100 with it on. i think mine has a vacuum actuator on the ip, im not too sure but i will check on this after this rain lets up

[95gltd]

both of my passats have a/c and they idle up with it on. goes from 1000rpm to like 1100 with it on. i think mine has a vacuum actuator on the ip, im not too sure but i will check on this after this rain lets up

did you get a chance to look? my 95 must have it also i hope.

[jtanguay]

I'm not sure if my car has the idle boost on it, but I do know that the car shakes, but my idle stays more or less the same (unless my needle is lying to me...)

[Powjetta]

My car has a small solenoid on the throttle that currently does nothing when the AC kicks on but I want to trace that back and see why and where it goes.  But first I have to put the head back on.

[Powjetta]

I guess that isn't a solenoid at the throttle, just a part of the upshift wiring.  It shouldn't be too hard to get a solenoid from another car that has this design and wire it in with the ac clutch.

[jtanguay]

http://vwdiesel.net/phpBB/viewtopic.php?t=579&highlight=diy

somewhere near the middle it talks about the idle ajuster for vehicles with air conditioning.  must have something to do with an idle booster for when the a/c is activated.

[Rat407]

Thanks for all the info. I need to go out and check to see if I have that one adjustment screw. Since my car came factory with AC and nothing has been changed that I'm aware of, I'm hoping it does and I can adjust accordingly.

[nkb]

i finally remembered to look to see and it is a vacuum thing on the pump the bring the idle up with the ac, im doing some more work to my car tomorrow and i can take pics if anyone is interested