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-   -   650i 06 idling too low (http://www.bimmerfest.com/forums/showthread.php?t=659090)

HULKED 11-19-2012 10:08 AM

650i 06 idling too low
 
Hi
I'm having an idling issue on my car......on cold start up it idles at 1100 rpm for @ a minute or 2, then drops down to 700 rpm for @ 4 minutes which at this stage it has a smooth & equal idle from the exhaust, after this it drops down to 550 rpm - rough idle & sounds like each bank has a cylinder misfire. I have done the vent valves (2 x diaphragms), check for any air leaks, had full system software updated, airflow meter (maf) has been checked,vavletronics settings been chanced from .3 to .8mm, spark plugs & coils are all good, there are no errors codes and no lights that appear on dash. Had my car by few BMW agents and they are unable to find any fault??? I have also been to a dealership that has same car as mine on sale & i done same idling test and it also started up at 1100 rpm(cold start) and when going down to the 700 rpm range.......it stayed on 700 rpm - with a smooth idle?? I'm suspecting software issue?? BTW I have been through the forum and haven't found no answers. Maybe someone can point me in the right direction, this would be appreciated.

lifezzgood 11-25-2012 08:43 AM

idling/low rpm issue
 
I sense you're more technical than I am on this but I wonder if we're having the same issue. When I run my car cold at low RPM's, for example driving slowly up a hill in my neighborhood, the car "knocks" as though it's not getting enough gas. Is this what you're experiencing?

HULKED 11-25-2012 09:32 AM

I don't have that issue, but have you had your car diagnosed to see if there's any fault codes? I ordered myself "Autocom" from China for @100usd to diagnose some other issues I had and saved me from running back & forth to dealers & saved alot of $$$. Works great with Windows 7.

lifezzgood 11-25-2012 10:00 AM

Thanks for getting back to me - I'm a mechanical idiot so I worry a bit whether or not any of the SW results will make any sense to me. :)

HULKED 11-25-2012 10:16 AM

Best bet is to start off by getting ur car diagnose to see if there's any errors. These cars are very sensitive in the sense of software related issues.

MakaveliFaison 11-25-2012 02:19 PM

May not be getting enough fuel. Clogged filter or dirty fuel rail?

davewoolley 11-27-2012 07:08 AM

What is the device you purchased?

HULKED 11-27-2012 07:15 AM

Autocom Cars Trucks & Generic

HerbP 11-27-2012 01:48 PM

If you had INPA or DIS, you could drill down in the software to help find your problems. Until you learn how to use the software, it is a bit confusing. There are many test you can run, to check to see where the problem is. The only way to learn how to use the software, is to start experimenting with it. If you think like a German, your learning curve would be accelerated a lot! Read below for more on this !

http://www.bmwcoding.com/

When the engine starts cold at 1500 RPM, the car is in the open loop mode. Once the O2 sensors & CTS have been satisfied, the engine goes into the closed loop mode. At this point all fuel & air is controlled by the ECM.

Hope this might help!

HULKED 11-27-2012 11:18 PM

I do a lot of programming on Bm's & other vehicles so it shouldn't be to difficult.I need to go thru the setting for fine tuning cos there is a imbalance between the two banks,so some specs would be appreciated.

Thanx Fred.

SFbay 11-27-2012 11:22 PM

Its a high chance you've got oil in your spark plug pipes

HULKED 11-27-2012 11:24 PM

Thanx they clean.

///Bruce 12-26-2016 08:23 PM

1 Attachment(s)
You ever find the problem? I have the same EXACT issue. I have been complaining about the idle was too high with the A/C on. But, it seems the idle with the A/C OFF is the problem. Idles rough at ~550RPM. If I want smooth, I need to turn the air on.

gavin77345 12-26-2016 08:32 PM

Does it only do the rough idle on cold start? I had a similar issue only on cold start. I posted a message under the title "Timing chain" you might want to read it


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mcdave71 12-27-2016 07:54 AM

My car idling at 500 in gear is very smooth. Bumps up to 750 with ac on and you can feel it pull against the torque converter more but still smooth. I think you're trying to mask the problem by idling it up. The way the intake is designed with the Valvetronic system, it's supposed to idle that low with no prob.

///Bruce 01-02-2017 10:08 PM

I had always thought the engineers managed to get the idle to stay the same whether on OR off. Ever happen in anyones else's car of the same quality? I already know the answer to that one. I originally bitched about the idle with the A/C on was way too high. Felt like I was really trying to brake harder than usual. So now, I believe it's the idle being too low. This causes it to idle roughly at a stoplight.

HerbP 01-04-2017 07:11 PM

Quote:

Originally Posted by ///Bruce (Post 9984500)
I had always thought the engineers managed to get the idle to stay the same whether on OR off. Ever happen in anyones else's car of the same quality? I already know the answer to that one. I originally bitched about the idle with the A/C on was way too high. Felt like I was really trying to brake harder than usual. So now, I believe it's the idle being too low. This causes it to idle roughly at a stoplight.

You are complaining over the brakes being to hard, & the idle to low at a stop light. Have you ever considered that your brake booster might be failing? This is a very common problem on our cars. If you think it is engine related, have you run a smoke test?

///Bruce 01-13-2017 04:43 PM

Hey Herb,

Talked to a BMW mechanic. I got the BS answer I was expecting: when the A/C is on, the idle is higher to compensate for the parasitic loss from the compressor.

I've been driving cars a very long time. I've worked on cars a very long time. If the car is at idle with no parasitic loss an idle speed is set. As more items are added (alternator, PS, A/C, ...), the idle is adjusted upward to compensate for the drop in RPM.

With the A/C turned on or off, the ECU accounts for it and adjusts the RPM so it stays the same. Not higher.

And, IMO, 550 RPM is way too low for our 650i's. Causes an unstable idle.

HerbP 01-13-2017 07:47 PM

This is per BMW, & the reason how the idle speed is compensated. There are a lot of variables involved.

Note the following points with regard to evaluating the idle speed setpoints:

- The clutch must not be operated

- Heating switched off to ensure the engine speed is not boosted to facilitate increased heating output

- All electrical loads switched off, no drive stage selected and no air conditioning

- The values may be slightly higher if the battery is discharged

- The values may deviate from the setpoints if the distance covered by the vehicle (mileage) is < 1000 km


Scope of test of idle speed setpoint/actual value comparison
Full operational reliability of the oxygen sensor after the catalytic converter serves as the reference for ensuring the same vehicle conditions.

The following values are tested:

- Smooth running values

- Engine speed

- Ignition timing

- Idle air adaptation

- Air mass

- Injection duration

- Load signal

- Opening of idle speed control valve

- Inlet camshaft position

- Exhaust camshaft position

- Idle-lambda adaptation, bank 1 +2

- Partial load-lambda adaptation, bank 1 + 2

- Idle adaptation deviation

- Voltage value of pedal position sensor 1 + 2

- Voltage value of throttle potentiometer 1 + 2

- Partial load adaptation deviation

mcdave71 01-14-2017 08:00 AM

You have to realize our cars are not like any other car. The way the intake system works on the N62 motor has no vacuum. The main throttle blade is there as a backup, that's all. Overall throttle is actuated by how much the intake valves are opened with the valvetronic system. This allows the motor to idle much lower and still be smooth. The reason for the idle up with ac on is not because of the extra load on the motor but to allow the ac to work better at the higher rpm.
I have turned off the idle up/ac on on my car and it's still perfectly smooth at 500 rpm with the ac on. You're chasing the wrong problem.

roseng 01-14-2017 10:41 AM

Quote:

Originally Posted by mcdave71 (Post 9977331)
My car idling at 500 in gear is very smooth. Bumps up to 750 with ac on and you can feel it pull against the torque converter more but still smooth. I think you're trying to mask the problem by idling it up. The way the intake is designed with Vanos it's supposed to idle that low with no prob.

Same for me. 500 RPM is right and my car is smooth. It's not a design flaw, that's the way it was designed.

If it's rough at idle than that is a different issue. Maybe a vacuum leak.

///Bruce 01-15-2017 01:05 PM

Quote:

Originally Posted by mcdave71 (Post 9998593)
You have to realize our cars are not like any other car. The way the intake system works on the N62 motor has no vacuum. The main throttle blade is there as a backup, that's all. Overall throttle is actuated by how much the intake valves are opened with the valvetronic system. This allows the motor to idle much lower and still be smooth. The reason for the idle up with ac on is not because of the extra load on the motor but to allow the ac to work better at the higher rpm.
I have turned off the idle up/ac on on my car and it's still perfectly smooth at 500 rpm with the ac on. You're chasing the wrong problem.

How did you do this? RSVP.

mcdave71 01-16-2017 06:43 AM

One on the programming parameters available. Buy a cheap cable for your computer.INPA Cable And learn how to program with it or go the MYCarly app and adapter to program the easy way. Adapter costs a little more but can program all bmw's.
Quote:

Originally Posted by ///Bruce (Post 10000027)
How did you do this? RSVP.



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