mgh44

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.

Skyhawk

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.

oldkid

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

MasterBlaster

"oldkid" wrote

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

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

http://autorepair.about.com/library/faqs/bl660e.htm

Andrew Rossmann

In article <1131164406.897832.232240@g43g2000cwa.googlegroups.com>,
o2pz5y402@sneakemail.com says...
> and what do these actuator valves do!?what's the function of this star
> wars creation of science?besides cost!!

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.

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mgh44

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