Alternator belt

Find a new mechanic. The alternator belt has nothing to do with idle speed.

OK... Someone tried to adjust the idle speed but could not lower it enough. What could be the problem, Ray?

The U.S. spec 1991 Tercel is fuel injected so engine idle speed is not adjustable.

Before you go through a lot of hoops to adjust the idle speed, you should find out what the cold and hot idle speed actually is on your car and compare it with the specifications on the sticker under the hood.

If idle speed is too high, check for a leaking injector (including cold start injector), bad cold start injector, and bad coolant temperature sensor.

Hey!

My Corolla GTS and my Celica GTS are both injescted, and there *IS* an 'idle speed adjustment' available. In the initake plenum, near the front, there is an 'air screw' that can be used to adjust the idle.

Now, on a very well maintained car that is running well, I would not touch this screw even though the manuals tell you to; (short...er, TE1 and E1, check timing and turn screw)

I wouldn't even LOOK at this screw on the Corolla or the Supra, but on my Celica GTS and another Tercel, I cranked that thing almost monthly!

Somewhere along the line, the idle adjustment screw on fuel injected engines went away because more people screwed things up than improved them. I think they were gone by the time the '91 Tercel came out.

Probably weren't neccessary any more.

Remember, my cars are all '80s models.

By '91 the ECU probably got sophisticated enough to take over this function.

IIRC, the adjustment screw was just an air bleed, it wasn't directly connected to the ECU. People who thought they knew what they were doing or who had expert race trained mechanic uncles would mess with the screw and cause problems. In all my years of futzing with problem cars, I have never had to touch that screw unless someone had messed with it before me.

Aw, now ya went and done it! You just described me! The only ones I ever did it with were the Celica with the old engine and a Tercel taht burned as much oil as gas.

In other words, who cared? :)

Oh yeah, another reason that the ability to adjust idle speed went away was easier compliance with emissions requirements, or keeping the car in compliance.