1999 Ford Taurus

Nov 05, 2005 5 Replies

Hi, just a question really. I hace a 99 Ford Taurus SE that only has



47,000 miles on it and today leaving work the service engine soon light came on. I took it straight to the auto parts store for a diagnostics check and they were all confused about the message, No one seemed to know what or where it was The message read P1518 Idle Speed Control Auxilliary Inputs which came up on their computer as "Intake manifold runner control stuck open". They told me I had to take it to the Ford house to get the answer to what that was. Can anyone tell me what it may be? Thanks and have a great day.

Is it the 24 valve engine? If it is, its a electric motor driven actuator, about $200 for a replacement part. It's a square box that sits on the front rocker cover and has a cable that goes back to a lever that opens butterfly valves in the intake runners.

and what do these actuator valves do!?what's the function of this star wars creation of science?besides cost!!

"oldkid" wrote

2 intake runners per cylinder. Low engine speed works better with 1 open. High engine speed works better with 2 open.

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At low RPM's, the butterfly valve closes, allowing only one intake valve gets air. This promotes lots of swirl in the combustion chamber, which helps reduce emissions, increases torque a bit, and help improve fuel economy. At higher RPM's, the butterfly valve opens, allowing both intake valves to breath. This allows the engine to generate more power.

On the early 2.5L version in the Contour/Mystique, this opening gave almost a 'turbo boost' effect during heavy accelleration. Later versions do a better job of smoothing the transition.

Not sure if it is a 24 valve motor or not. I will check and see then get back to you.

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