Mechanical Problems, Help.

[xicious]

I recently just bought a 91 celica, beautiful car runs great with one little exception. It idles for no reason, the minute you start up the car it starts idleing, the rpms are ranging from 1000 -2000. My dad's a mechanic and he automatically thought it was the intake gasket we replaced it and nothing happened, we sprayed carb fluid and there were no leaks. So now we're thinking a couple of things, an EGR valve is bad, the map sensor is bad, The O2 sensor might be bad, or the biggy the computer might be bad. Any suggestion guys, i'm mostly familiar with subaru and mitsu's and know nothing about toyotas you should've seen the hell i went through getting to the intake to change the gasket, toyota does not make it easy. Any help or suggestions would be really appreciated.


Thanks,
Xicious

[thousand_five]

Enjoy!

There is an adjustment screw on the carby.
You will find it near where the cable pulls on the pulley which opens the butterfly valve.
It limits how far the butterfly valve can relax back to the closed position (ie no air).Adjust yours so that the buttefly valve closes a little more.
You will probably want to return the dizzy to its original position.

There is also a second screw at teh base of the carby which controls how much fuel is put into the engine at idle.
You probably don't want to change it but if the pulley adjustment above does't work then try the second screw.

If all else fails, go to any mechanic.
This is a 2 minute job if the rest of the engine is healthy.

- Stepho

[Pineapple]

^There is no carby on EFI engine. There is an idle screw on top of the throttle body which may hide under a rubber plug.

Does it bounce up and down or seat stable?
Remove intake and clean throttle body with throttle body cleaner. Make sure you clean the holes at bottom of TB.
You may have leak below the intake manifold where there is 2 vaccum hose going to power steering pump. Could also be leak in brake booster.
Try unplug cold injector after engine get warm. If idle doesn't drop, you may need another cold injection switch.

[xicious]

It bounces but not very much. I'm pretty sure it's not the O2 sensor because it's telling the computer that something's wrong and the comp is trying to adjust so it's gotta be somewhere. I did a search and found alot of people having problems with the Cold Injec. Well i'll just keep trying stuff until i get it, i'm just trying to see what i should try first.

Thanks for the help.

Any more suggestions from anyone?

[aero92]

You're probably on the right track
There are 5 injectors, the cold start injector will give one idle.
When engine is warm the cold start goes out and the other 4 kick in.
The ECM will control idle on both cases.
Most likely your cold start injector is clogged or damaged.
Good luck!!

[toyomoho]

Does this fuel system have an IAC valve? This is an air bypass valve at the throttle body location. It helps maintain idle speed and controls idle up speed.

[xicious]

Well thanks everyone for the help. I just wanted to post a follow up just incase someone has the same problem, it turned out to be the map sensor. A fairly expensive part but once i replaced it everything worked well, i found someone else w/ a toyota and borrowed theirs popped it in my car everything worked fine, then went out and got one.

--Xicious

[89celicagts]

had the same problem with my 89.. it was from a vaccum leak on the egr valve.. it would idle between 1000-1800 once it got to 1800 it would drop back down to 1 then right back to 18.. check the egr valve and make sure all the lines are hooked up or better yet just replace it.. pretty easy job and not to much work involved

[xsurfer21]

true dat... same prob here and fixed it before i even drove it off the lot.