Do you have any guess why there's four terminals on the motor? The engine computer pulses the four coils inside the unit. As the armature turns to various positions, it threads the pintle valve in and out. As the valve backs into the housing, it exposes more of the air passage around the throttle blade. As more air is allowed in, the computer lengthens the amount of time the injectors are turned on. That's how idle speed is controlled.
You don't have to do anything to the motor; just stick it in. If you push the pintle in, the idle speed will be very high at start-up. It could take 5-20 seconds to come down to normal. When you stop the engine, the computer will pulse the motor enough to insure it is fully extended, then it will retract it approximately 50 "steps" in preparation for the next start. At start-up, the engine should go to around 1500 rpm, then down to around 800 rpm. That's called idle flare-up. There are 256 steps that the computer can place the motor in. These steps can be displayed on the hand-held computer that your mechanic can plug in to the vehicle. Step # 30 to 32 is typical for normal idle speed with a good running engine.
To give you an example of how much control the computer has, a Chrysler trainer demonstrated this on a Jeep V-8 engine about six years ago. He unplugged one injector while the engine was running. The computer increased the number of steps on the AIS motor to bring idle speed back up to 800 rpm. Next he unplugged another injector, and another; and another. Finally, with six injectors unplugged, the engine obviously was running very roughly, but it was still at 800 rpm; and it was only up to step # 180!
I second blakesfirstt's comments about antifreeze. It also contains water pump lubricant.
Monday, April 27th, 2009 AT 11:00 PM