1986 F150 Problem
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1986 F150 Problem
Ive got a 1986 F150, the problem is that right when I start it up it seems to rev real high right away and then idles back to a lower regular idle. It happens in a matter of seconds. I really dont know much about the problem so any help would be great! Thnx
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how high is high? is it all the time or when its is cold or hot or been sitting or what? are you seeing an increase in the rpms on a tach? or just hearing them? Could it just be the fan you are hearing? the clutch will be engaged when you first start up.
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Its pretty high, nothing extreme thoe, there is no tach im just hearing it. It happens all the time wether ive ran it all day or just hoped in, or whetehr its boiling or freezing its all the same. It sounds like the engine not the fan. It sounds as though i have the throttle ingaged 3/4 of the way then immediatly let off. Also sometimes if after it revs up like that, if i dont engage the throttle a little it may stall....
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From: South Carolina
Don't know how much this will help. Is your truck FI or have a carb? My wifes' 87 T-Bird does the same thing when its hot. It's FI and you don't touch the gas pedal when you start it, hot or cold. On cold starts it works fine, just like the choke on a carb. But when it's hot, computor does it's own thing, and you have no control over it. I hate it, makes you look an idiot. Starting the car, then imediatly rev the heck out of the motor.
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I have an 86 mine does the same thing but no stalling, I think that normal. You might have a gunked up Idle air bypass valve. On the side of the throttle body. It has a pintle in it you can clean with carburator cleaner, not the electrical part of it.Do you use fuel injector cleaner in the gas once in awhile?
griff777
griff777
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From: Illinois
I agree with griff. It IS normal. The engine needs more RPM's when cold to speed up warming among other things.
However, if it seems excessive, I'd also check for vacuum leaks. I've had to clean the IAC on my 86 a few times as well. It always seems to help.
However, if it seems excessive, I'd also check for vacuum leaks. I've had to clean the IAC on my 86 a few times as well. It always seems to help.
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I have an 86 F150 with a 347 stroker and pretty much stock EFI hot or cold it always goes into high idle for about 30 seconds no stalling though. What you describe is normal.try cleaning the air idle bypass and the passage it conects to for the stalling problem. hope this helps
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one thing you may want to look @ is the distr. mount control module. if the connector compound is thin or may vibration has loosened it just a lil bit it may give you this prob. remove it clean it retorque it and give it a shot...
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