I have a 1991 corolla dx. It idling high but i dont have a tach and I'm wondering how to go about adjusting without go to low so it stalls.
Barbeauty88
Some timing lights will indicate RPM's.
Pretty common really, your local auto parts store may loan them out.
Pretty common really, your local auto parts store may loan them out.
If the idle screw is all the way down, then there is too much air going through somewhere else at idle. Look for bad/disconected hoses. Remember, idle is not set with the throttle plate stop screw as it was for most of a century in most cars. That screw is screwed in just enough that the butterfly doesn't jam in the throttle body.
Just because you didn't touch the butterfly stop screw doesn't mean it is where it should be. Perhaps someone else adjusted it incorrectly once, or it was never right, or the screw tip dug in a little and the butterfly closed against the TB bore. If latter case, then car jumps when you are in first gear (manual) at idle, moving and first give it gas.
I would make sure there is a bit of slack in the throttle cable. Back off the butterfly stop screw. Then screw it in until it JUST starts to move the butterfly....basically, you want the butterfly closed with the load on the screw, not the edges of the butterfly.
I like to see a little slack in the throttle cable, so that temperature change or vibration or vehicle stance or something doesn't tighten cable and open throttle.
If you are trying to adjust the idle speed on a 4AFE engine, two terminals at the Diagnostics connector need to be shorted while adjusting the idle speed screw at the TB. If you don't, then you are going to confuse the ECU and it will try and revert back to it's previoius settings.
Other defective components such as a faulty ECT sensor or IDLE UP valve might be causing your higher than normal idle.
Just because you didn't touch the butterfly stop screw doesn't mean it is where it should be. Perhaps someone else adjusted it incorrectly once, or it was never right, or the screw tip dug in a little and the butterfly closed against the TB bore. If latter case, then car jumps when you are in first gear (manual) at idle, moving and first give it gas.
I would make sure there is a bit of slack in the throttle cable. Back off the butterfly stop screw. Then screw it in until it JUST starts to move the butterfly....basically, you want the butterfly closed with the load on the screw, not the edges of the butterfly.
I like to see a little slack in the throttle cable, so that temperature change or vibration or vehicle stance or something doesn't tighten cable and open throttle.
If you are trying to adjust the idle speed on a 4AFE engine, two terminals at the Diagnostics connector need to be shorted while adjusting the idle speed screw at the TB. If you don't, then you are going to confuse the ECU and it will try and revert back to it's previoius settings.
Other defective components such as a faulty ECT sensor or IDLE UP valve might be causing your higher than normal idle.
Peter finn's engine is different that these 6th gen 4A-FE engines. His has an electronic IAC valve. So that video isn't good.
First check that that the throttle is closing completely by grabbing the linkage with your hand and see if it will close more and lower the idle.
If it is closing completely then the idle adjust screw is directly above the the throttle axis of rotation. Your screwdriver will be pointing directly toward the rear of the car if you found the correct screw.
If you thermostat is stuck open and the coolant is too cold then that could be the reason for the high idle and you should fix that. There is also an idle-up for the AC and power steering, and if something is broken there it could be the reason for the high idle.
So you see you should verify everything else is correct before resorting to adjusting the idle screw.
The sticker on the underside of the hood will tell you the correct idle speed specification.
First check that that the throttle is closing completely by grabbing the linkage with your hand and see if it will close more and lower the idle.
If it is closing completely then the idle adjust screw is directly above the the throttle axis of rotation. Your screwdriver will be pointing directly toward the rear of the car if you found the correct screw.
If you thermostat is stuck open and the coolant is too cold then that could be the reason for the high idle and you should fix that. There is also an idle-up for the AC and power steering, and if something is broken there it could be the reason for the high idle.
So you see you should verify everything else is correct before resorting to adjusting the idle screw.
The sticker on the underside of the hood will tell you the correct idle speed specification.
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