Idle speed
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Idle speed
My new '95 F150 300-inch I-six idles at 1000 rpm. I am used to my former, '84 with same engine, that idled at about 650. I understand there is no idle adjustment, but my mechanic says he may be able to reduce it some. Why, with the high-tech computer, can't the Ford engineers make the engine idle a bit slower?
Posting Guru
Joined: Jun 1999
Posts: 1,525
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Idle speed
If it has always idles high,and, you and your mechanic have ruled out all possible vacuum leaks, includeing intake manifold vacuum leaks,there is supposed to be a throttle stop screw on the throttle body for just this purpose.After removing the plastic gaurd from the throttle body, you will see the screw plainly in sight. the problem is there isn't much of a head to the screw,but even Ford manuals say to turn it with pliers.Some other things to consider; high TPS voltage at idle; cold running engine which is directly related or the same as a Coolant Temp Sensor that is outputting a constant cold temp. signal to the computer,thus richening the fuel for increased idle.
Phillip
Phillip
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Idle speed
Check on the bottom side of your truck's hood; there should be a Federal Emissions Certification Decal there which has idle speed, timing, spark plug gap, etc. on it. Your truck should idle around 650 rpm, perhaps 750.
One possible cause for your higher RPM would be a 180 or 165 degree thermostat instead of the spec'd 195. The computer sees a "cold engine" condition and bumps the idle and fuel mixture.
Ed
One possible cause for your higher RPM would be a 180 or 165 degree thermostat instead of the spec'd 195. The computer sees a "cold engine" condition and bumps the idle and fuel mixture.
Ed
Postmaster
Joined: Jul 1999
Posts: 3,172
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Idle speed
Tall Paul ,
Im not sure what your engine should idle at , but Im thinking its like 650 to 750 Rpm. What I have always found on those engines is the air bypass vavle gets carboned up and the plunger sticks open a little more than it should . Its an easy fix ...Unplug its connection , detach it from its electric controller , unbolt it from the throttle body and clean it . I find Fords throttle body cleaner works great for things like this , it foams up and does a lot of the scrubbing .Maybe use a Q tip or pipe cleaner to bet rid of the heavier deposits in tight places .
Paul
Im not sure what your engine should idle at , but Im thinking its like 650 to 750 Rpm. What I have always found on those engines is the air bypass vavle gets carboned up and the plunger sticks open a little more than it should . Its an easy fix ...Unplug its connection , detach it from its electric controller , unbolt it from the throttle body and clean it . I find Fords throttle body cleaner works great for things like this , it foams up and does a lot of the scrubbing .Maybe use a Q tip or pipe cleaner to bet rid of the heavier deposits in tight places .
Paul
