Idle Speed Screw

[mrmora]

I was looking at the FSM to try and see where the idle speed adjuster screw is located. Not sure if I over looked that page, but can't seem to find it. I was looking through posts and it was mentioned it is behind or near the egr valve, is that correct? After I do locate it and I start adjusting the screw (slowly that is), do I need another individual to be in the car to hold the brakes down while the car is in neutral?

I've never adjusted the idle speed screw, so your tips and advice will be greatly appreciated!

[Petros]

The idle speed screw is on the carburetor main throttle shaft next to the the cable bell crank. If you take off the air cleaner and inspect closely where the throttle cable attaches to the carb throttle shaft. There is a some linkage between the bell crank and the actual body of carburetor, there is a large screw nearest to the carb body that is the idle speed, there is also a small one on the linkage between the idle speed and the bell crank, this one is the fast idle speed. The fast idle speed is for cold running when the choke is engaged, after the engine fully warm and the choke is fully open, than the normal idle speed screw will adjust the idle speed.

Also, do not confuse the idle speed adjustment with the idle mixture adjustment screw. this one is just over the EGR on the lower part of the carb body, and usually has a soft aluminum plug over the screw to prevent "tampering" as part of the emissions control system. If someone removed the is plug you will see the mixture adjustment screw down inside the bore of throttle body part of the carb, sometimes rebuilt carbs have this plug removed and than you can adjust the mixture screw. This screw is brass, the idle speed screw is galvanized steel.

These are two very different adjustments, are you actually looking or the idle speed screw or the idle mixture screw?

[mrmora]

Thanks for the clarification!

I am looking for the idle speed screw. I was talking to a mechanic a few days back about my blinking oil light. How it occurs when I'm idling in drive gear, yet when I am in neutral, the light doesn't blink. I told him that the light blinks in rhythm to the cars idle. After posting a previous thread about my blinking light, I followed the advice given by several members. I replaced the OPS and checked the oil pressure, all is good. The mechanic mentioned how I should adjust the idle speed, the car sounds like it's idling too low and that could be what is causing the oil pressure light to appear/blink.

[dlb]

if it is in fact the idle speed screw you are trying to adjust, i find i can adjust it without removing the air filter housing by just using a long screwdriver and a flashlight. shine a flashlight at the carb from the passenger side and you should see it.

i forget exactly but think the idle speed should be about 900 rpm for automatics. let the car fully warm up (the radiator fan should come on first so you know it's up to temp but then make sure the fan is off when you actually make the adjustment) and set the idle while it is in park.

on automatics there is also a transmission throttle linkage that needs to be correctly set. to check it, with the car off jack the front passenger corner up a little bit and put a jack stand under it. have a friend help or use a stick (i used a broken axe handle that i cut to fit for this job) to push the gas pedal to the floor and hold it there. crawl under the passenger side and look at the linkage that runs from the carb down to the bottom of the transmission. at the very bottom, you will see an arrow and a mark that it should point to. you will probably have to wipe some oil and crud away to see these. if they do not line up, pop the upper part off the linkage off and adjust the turnbuckle until the arrow and mark line up.

is your oil light still flickering, even after verifying the oil pressure is good and replacing the OPS?

[JesseN]

The FSM says my vehicle should be at 650RPM does this seem right or a little too low? The FSM also says to fully open the choke during setting. How do I open the choke?

[Petros]

you need to let it warm up all the way or the idle adjustment will not do anything since it is held up off the stop for the cold start fast-idle system.

I have not been able to get most Tercels to reliably idle at 650 rpm, an old worn carb, perhaps some minor vac leaks and not everything in the induction system operating "like new" makes it difficult get a steady 650. No harm comes from idling it a bit higher like at 800 rpm (that is where I like it).