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Thunder2

Rough idle when engine is cold... - BMW E60 545i 2004

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You are welcome.

 

The valvetronic is a beautiful mechanical thing. A motor (the actuator, part#11) drives a quadrant which turns like a second cam shaft which controls the amount of travel of the inlet valves. There is no main throttle valve in this engine as such, the engine speed is very simply controlled by how far the inlet valves travel. At idle they only travel *say 0.5mm, as you press the throttle the motor turns the quadrant further and increases the amount of inlet valve travel which obviously allows more fuel and air into the cylinders and the engine increases its rpms. Full chat and the inlet valve might be travelling say 5mm.  

 

There is a box of electronic trickery that controls the actuators. But if it faults I would expect a fault code.

 

Perhaps there is a mechanical fault on the worm drive of the actuator or a tooth missing on the quadrant. The motor turns but it doesn't engage and the engine stutters.

 

Instead of a throttle cable turning a butterfly valve, your right foot position is translated into differing travel of the inlet valves. Couple that with dual vanous and you have a seriously potent engine. Wish I still had mine, only for the noise of the two extra cylinders.

 

*I have no idea I'm just picking numbers for effect

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On 2 November 2017 at 10:15 AM, chrisgeary said:

Great video about Valvetronic from Engineering Explained:

 

https://www.youtube.com/watch?v=DKfcV7hITYI

 

Thanks, that is a great video. 

 

I always knew the X1 was just wrong

, the engine is mounted the WRONG way in the one in the video, a dead giveaway that it is a dreadful car!

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So, a BMW specialist thinks it's the valvetronics, which is a big job to do.  However, I did have a couple of guys say it could be an ECU issue and it may need looking at.  Does this, in any way, sound feasible or possible?  If so, how do I get the ECU number?

 

It may be barking up the wrong tree but it's at least worth investigating a little...

 

:o/

 

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Did you have any joy in the end?

 

My 745i has the odd misfire when cold which either disappears of its own accord or if I stop and restart the car. Haven't looked at ignition coils yet but I've had misfires on cylinders 3, 7 and 8.

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9 hours ago, DirtyHarry88 said:

Did you have any joy in the end?

 

My 745i has the odd misfire when cold which either disappears of its own accord or if I stop and restart the car. Haven't looked at ignition coils yet but I've had misfires on cylinders 3, 7 and 8.

 

Should be easy enough to swap the coil packs around and re read codes to determine if it is the coils.

 

When I did the spark plugs on my E60, my dad said I should have changed the coils too, but at over £30 each I decided not too! 

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hi all I'm new to this forum, but I my car have the same problem, rough idle only when cold start, the colder the worst. please halp!!!

one question is, does the valvetronics should work when it first start too or not, if not this could eliminate the valvetronics question, because I see somewhere said the valvetronics only work when the car warm up or moving, not when first start

 

Edited by 05545i

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The valvetronic works the whole time as that is how the throttle is applied to this engine. The valvetronic system alters the amount the inlet valve opens which is the throttle control on this engine. The more the inlet valve opens the more fuel and air mixture goes into the cylinders so engine speed increases.

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If it is the valvetronic, the fix involves replacing the idler arms but if that isn't something you fancy I have also read that adjusting the minimum lift for the valvetronic from 0.3mm to 0.8mm helps through INPA or DIS helps a lot.

Edited by DirtyHarry88

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Could be air temp.  If there is an issue with your MAF, it might struggle to recognise that the air temp is very low thus the air is denser and not adjust the fuel mixture accordingly.

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so if i adjust or reset the engine adaptation could help too, maybe? i did adjust the valvetronic to 0.8mm already, but now it's a bit warmer outside this couple of day, so it seem to be fine, but i will see next couple day the weather back to cold and give you an up date 

Edited by 05545i

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This issue is SOOO frustrating and I still haven't found the answer.

 

Part of the issue is I have no fault codes stored (thank you BMW!!!), just the Engine Malfuction code that comes up when it's cold.

 

To clarify, when I switch on, she runs fine, idling at 700rpm for about 2 minutes.  She'll pull off lovely and act like everything's ok, regardless of what the outside temperature is.  However, after I've driven down the road a bit, and when I'm sitting at traffic lights or waiting at a roundabout, she'll cough, splutter and the idle will wobble around 450rpm, just above stalling.  It's almost like, on turn on, the choke kicks in so it runs fine but then, after a couple of minutes, it's like either the choke has automatically stopped (in which case it's starving the engine of fuel) or that the choke is stuck on (in which case, it's flooding the engine). 

 

I've taken it to a few people (including BMW specialists), who say it's the valvetronics which are worn, and this is an expensive job to do.  But, I still can't work out why the valvetronics will work when first switched on and then wobble but then work again when the engine's warm?  With no fault codes coming up, it's basically guess work and it's easier to say it's a big problem like valvetronics, than to actually find another issue.  

 

 

I've had the lifters moved to their maximum electronically but this hasn't fixed the problem.

 

At the moment, I'm switching her on, letting her run for 10 minutes, switching her off and then starting off.  It still comes up with an engine malfunction code after a minute but at least she doesn't splutter and cough as much.

 

This seems to be a common fault on this engine so it ain't great from BMW.  :o(  

 

Anyone got any other ideas...?

 

I was going to see if it was an ECU fault but haven't done that yet.  Does that even sound like it could be feasible?  

 

 

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1 hour ago, Thunder2 said:

 It's almost like, on turn on, the choke kicks in so it runs fine but then, after a couple of minutes, it's like either the choke has automatically stopped (in which case it's starving the engine of fuel) or that the choke is stuck on (in which case, it's flooding the engine). 

 

 

I don't think chokes exist anymore, the engine ECU will vary the mixture depending on the input it gets from the various sensors.

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i've read through this to try and understand what's been tried & tested. I think you need to take a more methodical approach and rule out things one by one to narrow this down.  As you've mentioned it's when its cold (after a short amount of time) is the issue. You need to find out what the engine does on cold idle/start different to a warm start & eliminate ones that work correctly and narrow it down to the problem areas.

First thing i would do is make sure every plug & connector is attached properly. Use a contact cleaner  spray(something like GT85) to ensure the connections are all ok and no moisture is causing ill-effects. 

Then you need to work on a component by component basis to make sure they're running ok. One thing at a time so you can link any successes/failures to an individual item. 

 

 

 

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Electric throttle-valve actuator
The DME control unit calculates the position of the throttle valve: from the position of the accelerator pedal and the torque required by other control units. In the electric throttle-valve actuator, the position of the throttle valve is monitored by 2 potentiometers.
The electric throttle-valve actuator is electrically opened or closed by the DME control unit. With Valvetronic, the throttle-valve actuator is activated for the following functions:
• Engine start (warm-up)
• Idle speed control
• Full load operation
• Emergency operation

 

copy/paste from TIS, don’t know what temp they class as warm up.  I know from a cold start mine will idle at 1k for maybe 20 seconds, then 800ish for maybe 2 minutes before dropping to 500

 

I’d check both breather valves, one each bank under the round cap, ensure not split

 

check the breather hose from each bank to the manifold is OK, recently found mine brittle and cracked.  Failure of either can allow unmetered air into manifold and cause unsteady idle

 

Edited by Iain550
Addition

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Interesting about your idle speeds, mine would idle cold at 750rpm for only really a few seconds, possibly 30 max then very quickly drop to 500rpm and stay at 500rpm each and every time it idled.

 

My F10 idles much higher on initial start (1500k) up then drops in stages to 650rpm I think. It's very different to my E60 as it was bang on 500 each and every time.

 

 

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