Loses rpm in transmission drive position

1996 TOYOTA COROLLA
200,000 MILES • 1.5L • 4 CYL • 2WD • AUTOMATIC
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MARIOC68
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My car loses rpm when placing the automatic transmission in the drive position, sometimes to such an extent that the engine shuts down. By setting it to the neutral position the rpm is normalized.
Nov 28, 2017 at 7:40 AM
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MHPAUTOS
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Do you still have drive and do you have any other symptoms, does it feel like the transmission is locking up or the engine revs fall away to far in gear?
Nov 28, 2017 at 2:16 PM
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MARIOC68
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the revolutions fall even in the reverse position. When making the transmission changes I do not have problems with blocking. Only that the rpm drops a lot.
Nov 28, 2017 at 2:29 PM
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MHPAUTOS
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May be look at the idle air control system, as load comes on the engine via transmission load, the IAC should maintain a good idle, look at doing a base idle re set and check the iac valve as well.
Nov 28, 2017 at 6:37 PM
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MARIOC68
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To open the air control valve (ACV) two current signals are needed, one positive (+) and one negative (-). According to my electric diagram of the EFI system, the positive one is delivered to me by the main relay of the fuel injection circuit, it is the same one that feeds the gasoline pump. The other signal, supposedly negative, is given to me by the ECU. How can I tell if the ECU is sending a signal to the ACV? Already verify the removed ACV, connecting it to the battery directly, and it works correctly, that is, it opens the valve.
Nov 29, 2017 at 1:29 PM
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MHPAUTOS
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Back probe the ACV with a multi meter and check for a circuit, maybe do a continuity check from the plug back to the ECU as well you may have a high resistance or an open circuit.
Nov 29, 2017 at 9:18 PM
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MARIOC68
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the ECU was not sending a signal to the ACV (IAC). I had it repaired now it comes signal like pulses, is this form of operation correct? you can also hear that the valve works by clicking with a click.
Feb 11, 2018 at 3:38 AM
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STRAILER
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Yes you might be able to hear it work. Does it seem to run okay?
Feb 12, 2018 at 12:14 PM
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MARIOC68
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Yes, I can perceive it at the ear and at the touch. This work, I tried disconnecting and reconnecting the valve, you can see how the revolutions go up and up in each situation. Even before the rpm dropped when placing the lights, now no longer.
Feb 12, 2018 at 12:36 PM
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MHPAUTOS
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This is a stepper motor and from what you describe it is working fine.
Feb 13, 2018 at 3:49 AM
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MARIOC68
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Right. Give the problem resolved.
Thank you very much.
Feb 13, 2018 at 6:30 AM