motorboating
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motorboating
motorboating is what I call it but my truch idols up and down constantly. Ive always associated it with a vacuum leak. However I can't seem to fix it. ANY suggestions? I have a 1985 F-250 with a fuel injected 302
HELP
HELP
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Joined: Jan 2001
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From: Virginia
1st thing to do is take the throttle body apart and clean it with carb cleaner. Clean the idle air motor also, but don't get carb cleaner on the motor itself. Put it all back together and get it running. If it still does it, unplug the idle air motor while it's running. If it still is idling pretty high, adjust the idle stop screw till the engine is barely running about 500 rpm or less. Then turn it off, plug the idle air motor back up and re-start it. Rev it a couple of times and let the computer "learn" to control it, and see if the problem finally goes away.
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Joined: Sep 2009
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1st thing to do is take the throttle body apart and clean it with carb cleaner. Clean the idle air motor also, but don't get carb cleaner on the motor itself. Put it all back together and get it running. If it still does it, unplug the idle air motor while it's running. If it still is idling pretty high, adjust the idle stop screw till the engine is barely running about 500 rpm or less. Then turn it off, plug the idle air motor back up and re-start it. Rev it a couple of times and let the computer "learn" to control it, and see if the problem finally goes away.
Is there also a method to reposition the TPS sensor? Along with a point to grab base(idle) voltage from?
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Joined: Jan 2001
Posts: 56,997
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From: Virginia
If the TPS is adjustable(some are not) it's done with a voltmeter on the TPS wires. As was previously mentioned, you should not touch the idle stop screw, but by the time they write in, it's too late for that. A certain amount of air is supposed to go by the main butterfly, and the rest goes through the idle air motor passages. 90% of the time, the butterfly is coked up with carbon, and that disturbs the air balance.
Postmaster
Joined: Apr 2003
Posts: 2,703
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From: Harrisburg, NE
the tps has three wires running to it, a reference, a signal, and a ground. if i remember right the signal is green. you want to backprobe it (jumper wires or it needs to be plugged in, key on) and then slightly loosen the screws and twist until you get as close to a .99 volt reading without going over .99v
I find it easer to do the adjustment with the throttle body unbolted from the intake, as its on the bottom. but thats ok cause your gonna clean it right?
I find it easer to do the adjustment with the throttle body unbolted from the intake, as its on the bottom. but thats ok cause your gonna clean it right?
