A/C compressor causing low idle

Rich L · 06-10-2002, 10:41 AM

Is there a solenoid that controls the idle when the factory A/C compressor turns on? If so, where is it located?

My car idles smoothly at 950 rpm with the A/C off. With the compressor on, idle drops too low and the car stalls.

Thanks in advance!

Decolliber · 06-10-2002, 11:02 AM

Should not the idle be around 800rpm? Perhaps the idle has been turned up to conceal some other problem.

Rich L · 06-10-2002, 11:26 AM

Idle is set correctly at 950 rpm. Is it possible to lose vacuum when the compressor kicks in?

SeaDweller · 06-10-2002, 05:38 PM

What type of compressor is it?

The old compressors were a heavy load on the engine, which is why many folks upgrade to the Sanden or other more efficient compressors. My RPM's only drop by 50 when the A/C is kicked on, so I keep my idle at 1,000.

john walker's workshop · 06-10-2002, 05:49 PM

later 930s had a switch that blocked vacuum to the vacuum retard diaphram on the distributor when the a/c was switched on. when the retard looses vacuum, the idle goes up. you could fit it to your car.

Rich L · 06-10-2002, 07:37 PM

It's a York compressor. For now, raising the idle seems to be a temporary solution. I'll look for a different compressor or the 930 switch.

Thanks guys!

Joeaksa · 06-10-2002, 08:55 PM

Rich,

The York is a boat anchor! Try a Sanden or other rotary compressor. BTW, for my 85 model using the NiponDenso rotary compressor, the same unit was used on the following American tanks:

Nippon Denso model 10 P 15C SA: 87 Mercury Lynx, 88-90 Merc Sable 3.8l or 82-87 Toy Celica

You can get one a lot cheaper by asking for a Merc Sable or like compressor than saying the "P" word at the parts store.

Joe

SeaDweller · 06-11-2002, 06:08 AM

John,

Could the vacuum switch be fashioned to fit an '83SC motor with '78 Euro intake system?

Kemo · 06-11-2002, 08:49 AM

Joe,
Will the Nippon Denso unit bolt right in? Is the clutch groove diameter the same? If so, this would be a good find at a salvage yard...

Thanks,

Rich L · 06-11-2002, 11:30 AM

Not sure, but I think the Nippondenso compressor only fits '84-'89. For '83 and earlier, the Sanden compressor relpaces the factory York.

Some A/C info here

john walker's workshop · 06-11-2002, 12:03 PM

micheal, the switch simply gets power when the a/c is switched on. so it could be spliced into the a/c clutch wire. the only question is the different degrees of retard between the 930 and 911 retards, ie; how much would the idle speed go up on yours as opposed to the 930, when the retard is negated.

Joeaksa · 06-11-2002, 12:59 PM

Steve,

Not sure if the ND will bolt in but you could go to any local auto parts store and borrow one and take it out and give it the quick eyeball check.

Not sure how the mounts were on the old Yorks... but sure am glad that I do not have one!

I am going to attempt to overhaul my ND compressor next week. Have the overhaul kit, and tools needed to take it apart. After all, this is not rocket science and all I can do is waste $20 worth of "O" rings then have to trade it in as a core on a overhauled one if it does not work.

Joe