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I have been experiencing intermediate high idling (700-800rpm) for quite sometime now. The engine normally idles at 500rpm. Every once in a while idle increases to 700-800rpm (most of the time on start(warm), rarely when the engine is working) and I can feel a huge increase in gas consumption as well as slight decrease in performance. Btw, NO CODES whatsoever. Can any1 help?
Last edited by EURO540M; 11-24-2011 at 12:57 PM.
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I'd be looking at the idle air controller, I played hell trying to figure out my erratic idle, even had cleaned the IAC and it tested working, it finally went all the way bad and the idle was bouncing all over, replced and all is good again.
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Did you mean Idle Control Valve (ICV) by idle air controller?
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That was my first guess too. But, the dealer told me that 2003 540i does not have ICV. Its build-into the throttle body, which was replaced apprx. a year ago. I did not notice to have that problem until last 6-7 months. Idk, maybe its defective, but theres no CODES, otherwise I would have taken it back to the dealer since they offer 2yr warranty on parts. Can it be a small vacuum leaks and not the throttle body itself?
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If you are talking upon startup you get the high rpm's this is normal for it to run around 700~800rpm your secondary air pump is on. After about a minute it shuts off and you rpm drops to the normal 500ish. Does it do it while the car is warmed up and your parked idling?
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No, I'm not referring to a cold start. I happens when the engine is warmed, parked, on drive at all times and its not normal. I can feel a huge increase in gas consumption. Its very random. When it goes back to normal 500rpm everything seems fine.
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Can anyone relate to this problem? or knows why this is happening?
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Does it happen when the car is sitting for a bit? Because they do kick into high idle (700rpm) after like 5-6 minutes to up coolant circulation.
Yes, a vacuum leak can cause a high idle. It'll usually set some sort of code though, but not always. I would have the intake smoke tested, since these engine's are prone to leaks.
Last edited by deathwarden5; 11-27-2011 at 03:35 AM.
Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car.
Horsepower is how fast you hit the wall, torque is how far you take the wall with you.
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No, it has absolutely nothing to do with the engine being cold. This occurrence is very random.
I think so too... its a vacuum leak most likely. Looking forward to the smoke test.
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In regard to what I was saying, they will kick into high idle WHEN HOT and sitting, to increase coolant circulation. If the car is fully warmed up and at operating temperature, it will go into high idle after 5-6 minutes to get coolant flowing.Originally Posted by EURO540M
Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car.
Horsepower is how fast you hit the wall, torque is how far you take the wall with you.
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I will consider that. Thanks for the info. Meanwhile, I'm looking forward to the smoke test.
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Any codes?
Ooops just read that there were no codes.
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Did ever figure out what the problem was , for the idle between 700-800 rpm. I am having the same problem .
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Yes I have come to conclusion some time ago. I found it to be normal operation of vehicles charging system. When my 540 sits at idle 15+ minutes (less with xenon low beams on - high voltage) it automatically increases the idle which raises alternator output to charge the battery. After vehicle is driven at cruising speeds for x amount of time and sometimes key cycle idle speed returns back to normal.
Last edited by EURO540M; 11-20-2017 at 08:38 PM.
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