High Idle and no A/C problem
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High Idle and no A/C problem
My 6.8L Excursion is idling high after it gets warmed up. But the problem only happens if I try to use the A/C which stopped working about the same time as the high idle showed up. If I leave the A/C off I notice the idle problem never shows up. I took it to my dealer but I was told the problem is likely with my Cylinder Head Temperature Sensor. This sounded really strange to me seeing has how that sensor is for controlling an engine overheating issue. I am not sure if these two problems are related. Could a vacuum problem be at fault? If the A/C needed to be recharged would it cause my high idle problem? Any suggestions?
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Hmm, don't know if I can be of any help or not, but just for clarification, does the high-idle occur with just the fan or does the A/C compressor have to run? (if you have the older manual temp. controls, check your owner's manual, because the A/C compressor runs with most, but not all, of the fan modes (ie. feet only, MAX A/C, panel only, defrost etc...)
Also, if you turn on the fan, does the air blow out of the defrost vents or the regular vents (if it only blows out of the defrost vents, one more sign you might have a vacuum issue)
Hope that helps!
Also, if you turn on the fan, does the air blow out of the defrost vents or the regular vents (if it only blows out of the defrost vents, one more sign you might have a vacuum issue)
Hope that helps!
Hotshot
Joined: Jan 2004
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From: St Louis
Your idle is high BECAUSE the A/C compressor isn't working. Fix the compressor problem and the idle issue will go away once the computer relearns strategy.
In normal operation, the computer nudges the idle control up a bit to compensate for the additional load of the compressor. If the extra load doesn't show up, the engine runs faster.
Visit the HVAC forum and check the FAQs for the A/C problem.
Steve
In normal operation, the computer nudges the idle control up a bit to compensate for the additional load of the compressor. If the extra load doesn't show up, the engine runs faster.
Visit the HVAC forum and check the FAQs for the A/C problem.
Steve
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AFREEMANMD, You're right, If I leave the switch in the OFF position. I have no idle issues at all. If I use any other position I do eventually get the idle problem But it is worse when I put it in A/C or MAX A/C. There was a morning when I could swear the defrost was blowing cold air but I will have to try it again to make sure.
Also, originally the A/C would still work when I was on the highway, but once I slowed down, it would start to blow hot air. I would have to turn it to OFF for a few minutes then back on again to get it to blow cold. I didn't know the A/C still ran in the other positions.
Also, originally the A/C would still work when I was on the highway, but once I slowed down, it would start to blow hot air. I would have to turn it to OFF for a few minutes then back on again to get it to blow cold. I didn't know the A/C still ran in the other positions.
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Thanks for the help! I finally fixed the problem. It was infact the Cylinder Head Temp Sensor. The two wires that go to the sensor were damaged just behind the connector. (Probably a lousy mechanic placed his hand on them at one point and crushed them. ) Once I repaired them my a/c compressor kicked back on and works like a champ again. I am glad I found the problem and did not let the dealership replace the sensor like they suggested. The idle problem was also cured by this.
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Joined: Aug 2006
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Thanks for the help! I finally fixed the problem. It was infact the Cylinder Head Temp Sensor. The two wires that go to the sensor were damaged just behind the connector. (Probably a lousy mechanic placed his hand on them at one point and crushed them. ) Once I repaired them my a/c compressor kicked back on and works like a champ again. I am glad I found the problem and did not let the dealership replace the sensor like they suggested. The idle problem was also cured by this.
