Re: ANyone ever replaced a tranny in a 88 750il (archive)

Correct - the 750iL does not have a throttle position switch. I am referring to the pedal position sensor that has a module with a relay that tells the car to switch between idle mode or load mode. I was suggesting the module might be bad. This is handled through the Electronic Motor Load Module (EML) and a relay (switch) activated by the pedal position sensor which is located under the accelerator pedal. When no pressure is on the gas pedal the Pedal Position Sensor tells the EML to place the engine in "idle mode." When pressure is placed on the pedal the EML begins increasing RPMs as the pedal is depressed. There is no linkage here, it is all controlled by a module with a relay inside.

The Throttle Position Switch (TPS) is available on the 735iL and is located on top of the engine at the intake manifold.

According to the local BMW Master Mechanic when you first turn over the engine all 12 injectors are open to do a "cold engine prime" until the Crankcase Position/RPM Sensor locates where the engine is. Then the ECM tells which batch of injectors should be turn on and which should be turned off. The Owner's Handbook calls this an "Automatic Cold Start." If the EMC does not receive a signal from the Crankcase Sensor the engine won't start.

The 750iL has several different transmissions available. David F is correct about the connectors. The AEGS is the transmission module and it communicates directly with the valve body on the transmission. I have had a few mechanics tell me to reset the transmission module by unplug the battery for at least 24 hours. After you start the car let it idle for at least 10 minutes so the other computers can reprogram themselves.

David S.

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