Hi to all experts in auto transmission, i have a problem with my car stalling when placing gear selector into drive or reverse but not neutral. It occurs also when RPM is at its cold starting indication of around 1000 -1100 rpm. After idling for 2 minutes rpm drops below 1000 rpm and transmission operates normally, and selecting drive /reverse is very smooth and not clunky. Can someone please suggest something? Kind regards Ash
My car has 85000 miles.
My car has an automatic transmission.
The torque converter and torque converter lock up solenoid should be evaluated. Another possibility is an internal hydraulic leak in transmission seals causing pressure to apply both reverse and forward gears at the same time, lock up the transmission and stall the engine. Pressure testing (external gauges) can be used to see if such a leak is caused by a leaking seal or a leaking reverse or forward solenoid/valve.
Another possibility relates to engine controls. Test the throttle position sensor, idle control valve as well as the manifold absolute pressure (MAP) sensor. The MAP sensor detects engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The ECU uses this information to adjust ignition timing and fuel enrichment relative to the amount of power needed. When the engine is working hard, intake vacuum drops as the throttle opens wide and the engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the MAP sensor, it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation (spark knock) that can damage the engine and decrease performance. IF the MAP sensor is faulty, this foregoing sequence may explain why the engine dies as you put the vehicle into gear as a load is put on the motor.
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