A/C Idle Speed Issue - Toyota Nation Forum : Toyota Car and Truck Forums

Kiasis · 08-01-2006, 09:55 PM

1988 GTS. When A/C is on, idle speed drops to around 500 rpm and sometimes stalls out. I have previous owner paperwork that back in 1995, apparently same problem was diagosed by dealership as "vacuum switching valve for A/C idle up" needed to be replaced. The part was described as "valve, magnet."

I can't find any part by identical or similar name from any part store. Anyone know the current name of this part, as the problem does sound identical. Thanks, Pat

Doctor J · 08-02-2006, 11:07 AM

This part is common to fail due to the way the coil wire of the solenoid is spotwelded to the teminals inside the casing. On my last visit to the wrecking yard, I have found about 7 out of 10 were defective. You basically can use any Toyota idle-up solenoid for a/c, providing it has around 40 ohm resistance. I used one from 83 camry on my 87 wagon, however, the wire connector needs to be spliced, but the wire colors are the same, so polarity will not be reversed. Prior to procceding, double check the resistance of the solenoid you presently have. The older designs with pigtail connectors are much more robust compared to these used in 87-on.

Kiasis · 08-02-2006, 02:00 PM

THanks, Doctor J. I appreciate the assistance. Can you direct me to the location of the idle up valve? Thanks again.

Doctor J · 08-02-2006, 02:56 PM

It is located on the firewall next to the windshield wiper motor, black cylindrical part, about 1 inch dia., 2 inches long, has two vacuum hoses attached to it and plug-in wire connector.
Make sure that these hoses are not disconnected from it, then measure its resistance.

dannyc928 · 10-26-2006, 03:41 PM

Hi Dr. J,

I'm having the similar problem with the idle on my 1989 Celica GT (3SFE). Whenever you turn on the A/C, the idle drops below 500rpm and the whole engines shakes like it's on the verge of stalling. My question is: Are the hoses attached to the VSV under pressure? Do I have to purge the pressure first or simply remove the hoses? I've been reading this forum for a few days now trying to research this problem and the end results seem to be the vacuum switching valve. Do you know if it could be something else? Just double checking before I shell out money for the part. If the hoses are under pressure then I'll have to have the dealer replace it then.

I appreciate the feedback and any feedback from the forum.

Thank you,
Dan

***toyomoho*** · 10-26-2006, 08:04 PM

If you are talking about the small diameter flexible rubber hoses to the VSV, the system runs on vacuum from the engine intake manifold. The hoses should be just pushed onto the valve by hand.

You can test the solenoid valve using the ohm test or attempting to pass low pressure air through it when on. Or bypass the valve with some type of connector and see if the engine idle rises.

Doctor J · 10-27-2006, 08:17 AM

If the by-passing the solenoid like Toyomoho suggested will not bring the rpm up, the diaphragm inside the air control vacuum switching valve may be leaking.

leanna8 · 11-03-2006, 11:10 AM

ty you guys this is also one of the first things I found about mine. It stalled at an intersection and was running poorly when I had the air conditioning running and as soon as I turned it off it was fine. We will be looking into this. I also noticed though that it made my RPM's go crazy on the monitor in my car. I am assuming that is still the same problem?