I have a 1990 240 sedan- where is the idle control valve, and how do I adjust it? thanks

my volvo died on me- so I took it in, and the mechanic installed a new air flow sensor, and told me it would be drivable. he said it needed a tune-up, but wanted 200 bucks for it, so I told him I'd do it myself. I ordered the tune up parts from IPD for around 65 bucks. after he returned the car from the shop, I took it for a drive, and it kept dying- it wouldn't idle correctly. It re-started easily every time, but when I threw it into gear and started to let off the clutch, it died almost every time. I haven't done the tune-up yet, should that solve the problem? I called him today, and he said that the idle valve needed to be adjusted after I did the tune-up. any suggestions?

It doesn't sound to me like he was trying to be deceptive. Your year/model just doesn't have aidle control valve. You can adjust the base idle by adjusting the screw stop that stops the pulley thing attached to the throttle cable. However, You really shouldn't need to. Do the complete tuneup - new plugs, wires, air filter, cap, rotor, and if you don't know when the fuel filter was last changed, do that as well. Then, if you still have the problem come back to this board and ask your question again.

No deception here - 1990's do indeed have an IAC. Actually I've never heard of an LH 2.4 that didn't. Anyway...

The IAC is not adjustable. The opening angle is normally controlled by the ECU (Engine Control Unit). In the event of a problem and the ECU is unable to control the ECU (bad wiring, bad IAC motor, etc.), in the unpowered state the IAC should return to a failsafe, partially-open position by an return spring.

The adjustment on the throttle cable is for wide-open throttle adjustment only. There is a small throttle stop screw and locknut on the throttle lever, but that is not an idle speed adjustment and in most cases should rarely be touched. (This isn't your father's Oldsmobile.)

A major component of the idle speed system is the throttle position switch, attached to the throttle shaft. The TPS contains two switches, one to detect closed throttle and the other to detect full throttle for fuel enrichment purposes. Only when the ECU senses closed throttle does it attempt to maintain the engine speed above the preset limit.

You should hear a distinct 'click' from the TPS when the throttle is cracked open. The manual states the switch should be closed with a .15mm feeler gauge between the throttle lever and the throttle stop screw, and should be open with a .45mm gauge.

Check for vacuum leaks, especially in the intake 'snorkel' between the AMM and the throttle body. You have to remove it to check thoroughly for leaks, since they usually occur on the underside where it rubs against the fender well or other stuff.

There isn't a knob such as the one on an '81 B21F or an '85 B230F. Idle speed on the later cars is controlled by the idle speed motor, temp. sensors, throttle position sensor and an idle adjust screw. Is your car idling too high or too low? Suggest you check the archieves on this - there's lots of info. on idle "issues" there.

The valve is not user adjustable. If you're having idle control problems it may be due to many factors incl a faulty IAC, which is below the intake manifold.

First, take the throttle body out and clean it. You should also clean the flame trap and replace hoses and make sure the vacuum is OK and not bad or leaking hoses.
On these years there is a common ECU fault that leads to a poor idle, but you should elliominate all other possibilities first before replacing it.
--
'89 245 Sportwagon, '04 V70 2.5T Sportwagon

It doesn't exist on the year