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Thunder2

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

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Hi,

 

I've been reading lots about rough idles on the 545i but haven't found a definitive answer or same set of circumstances.

 

I have a 545i, 2004, 108k on the clock.  It runs lovely, lots of power and very smooth.  Except:

 

In the mornings, it runs like there's an error in the fuel mix.  It stays at about 500rpm and is close to cutting out, as if it's running on 7 cylinders.  However, after about 10 minutes of running rough, I can switch it off and, on startup, it'll be fine for the rest of the day. So, it's just rough when cold.

 

I've had the coil packs changed, it's been serviced, spark plugs, etc.  

 

Could it be a sensor or something, giving the wrong readings so getting the fuel mix wrong, up until it comes up to a standard running temperature?  It doesn't give any error codes, but it comes up with Engine Malfunction.

 

Any ideas or pointers would be very much appreciated.

 

Cheers,

Ron

 

P.s., And what's with the car not  having a temperature gauge?  What happens if it gets hot???

 

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Wouldn't a stuck lifter tap the gap?

 

Other possibilities (guessing here) could be an air leak in the inlet somewhere, causing mixture too lean when cold instead when richer is required. Or maybe a sticky idle control valve but that can resolve if you jab the throttle.

 

The temperature reading can be monitored with some push button magic and summing the end of the VIN number.

 

https://www.youtube.com/watch?v=mSMri13Tm-w
https://www.youtube.com/watch?v=IB4vtoiFy7c

Edited by DarkHorse
typo's

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When I had my E39 525i (M52 engine I think) it used to run rough whilst coming of choke on cold starts and if I switched it off and back on again it would be fine. Mine was diagnosed as a sticky lifter.

 

On the odd occasion when it did not run rough on a cold start you could clearly hear the gap tap.

 

Hope that helps.

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Just now, jake13 said:

Secondary air pump? @535i Andrew is your man, he had two of these.

 

Thanks Jake.

 

Yup, I had similar. Turned out it was the two cylinder head breather caps.

 

Fault code on mine indicated lean running, too much air getting in via dodgy valves.

 

Local Indy couldn't help but nice friendly BMW dealer found it after a bit of head scratching. Parts were about £10 each but with diagnosis time it cost £200 all in so quite happy.

 

Part replaced on mine was #13

 

But mine would run fine when cold and only fault with engine malfunction when warm. Once up to temp the yellow light would come on but yeah on idle it sounded like it was running on 6 and 3/4 cylinders, but would still pull like a train and scare Porsche drivers with the fault.

 

@Thunder2, how is your engine for oil leaks?

 

Look out for cylinder head cover gasket leaks, I lost 1.5 litres thanks to my right hand bank.

Vacuum pump to upper timing case o ring.

Vanos o ring to upper timing case.

Alternator braket oil leak.

Upper timing case to block.

 

If it can keep its vital fluids where nature intended its a nuclear bomb of an engine, allowing you to scare Porsche drivers, but to the uneducated it looks like an aga equipped 520d. 

 

There is no such thing as no overtaking in one of these things.

 

I miss the V8 bellow on full chat when the valve in the exhaust opens up.

 

I need to make peace with myself that I'm unlikely to ever own a V8 again thanks to the ecomentalists running the county and banning new cars with proper engines from 2032.

 

 

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I think the oil's good. Sorry, I'm not that mechanically minded but there was an air leak from the rocket cover gaskets so the rocker covers and gaskets were both replaced. It didn't fix the problem. If it's the valvetronics, it sounds like a big job? 

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Update.  I took my car to an auto diagnostic place and, after a couple hours testing, he unhooked the Air Mass Sensor (Bosch Part:  0280218135).  Now, she starts and runs fine with no problems when cold.  I 'think' that bypasses some air/fuel mix settings and gets the engine to run with a slightly richer mix.  There might still be an issue elsewhere but the richer mix (and higher fuel usage) is making the car run great.  I've ordered a new sensor (afterwards, I figured I should have cleaned the old one first!) and will fit this when it comes in.  Hopefully it'll sort the issue.  If not, the issue could be elsewhere.  I'll update when the new sensor comes in.

 

Any thoughts, anyone?  

 

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7 hours ago, Thunder2 said:

Any thoughts, anyone?  

 

 

Other than my previous post, if it doesn't cure it, get your codes read. Also change your engine air filter to give the new air sensor a good start in life.

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Ok, more updates.

 

I replaced the MAF sensor (£100 for the part (a proper Bosch, like for like replacement), £80 for the diagnostic) and the next morning, she was still running lumpy.

 

I've now taken her to the last place I'm going to go to before I go to the BMW dealers (perhaps I should have gone there first?).  These guys only deal with Porsches and BM's so they should know their stuff.

 

After a couple of hours of diagnostics, they still can't find the problem.  They're saying their educated guess would be to replace the mapped thermostat. Cost to do that, with diagnostics as well, approximately £250, but this will not guarantee the problem will be fixed.

 

Can anyone in the know shed any light on this?  Does this sound feasible, could it be miles out?  I don't even know what it does, or what the part number is, I just know it's not the map sensor, which is at the top of the engine.  The mapped thermostat is on the front of the engine.  Could anyone give me a a site where I can track this part number down, or where I can see what it does?

 

As always, any advice is much appreciated.  :) 

 

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On 28/09/2017 at 7:39 AM, 535i Andrew said:

 

Other than my previous post, if it doesn't cure it, get your codes read. 

 

Did you check the breathers out?

 

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On 13/10/2017 at 1:41 PM, Thunder2 said:

Ok, more updates.

 

I replaced the MAF sensor (£100 for the part (a proper Bosch, like for like replacement), £80 for the diagnostic) and the next morning, she was still running lumpy.

 

I've now taken her to the last place I'm going to go to before I go to the BMW dealers (perhaps I should have gone there first?).  These guys only deal with Porsches and BM's so they should know their stuff.

 

After a couple of hours of diagnostics, they still can't find the problem.  They're saying their educated guess would be to replace the mapped thermostat. Cost to do that, with diagnostics as well, approximately £250, but this will not guarantee the problem will be fixed.

 

Can anyone in the know shed any light on this?  Does this sound feasible, could it be miles out?  I don't even know what it does, or what the part number is, I just know it's not the map sensor, which is at the top of the engine.  The mapped thermostat is on the front of the engine.  Could anyone give me a a site where I can track this part number down, or where I can see what it does?

 

As always, any advice is much appreciated.  :) 

 

The MAP thermostat runs the engine at approx 105 oC, the ECU allows control of the thermostat down to approx 90oC when the engine is under load, it does this with a built in heater in the thermostat body. 

 

When my thermostat failed  I had a code for MAP stat mechanical, engine never went above 90 degrees. I replaced stat and the engine ran at 107 afterwards. Had no running issues whatsoever, just a fault code for the error

 

+1 for checking breathers 

 

I believe the valvetronic doesn’t control throttle until a certain engine temp, until then it’s the throttle body controls engine, is this clean and error free

 

do you have any DME fault codes?  Unless you have a bottomless wallet appropriate fault codes are the only way to accurately diagnose these engines, parts throwing is never the answer

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From memory the only throttle control on the N62 is the valvetronic as the butterfly valve in the throttle body is for diagnosis use only.....I'm sure I read that in TIS....been a while now right enough.

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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 (aircon off). Mine is TU engine so doesn’t have the secondary air pump so may behave slightly different

 

does the OP engine idle at 500 straight away from a cold start? If so seems too slow until the engine is at operating temp.

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Hi Iain,

 

On startup, she runs fine.  Starts lovely, sounds great.  I get 300 yards down the road and she starts spluttering like a 70 a day smoker.  Revs go from about 1000rpm down to 500rpm and she struggles to keep awake.  I have traffic lights all around me so it's always a bad way to start the day, waiting at lights wondering if she's going to conk out.  Not a good look for such a lovely car.

 

Regarding the:

"With Valvetronic, the throttle-valve actuator is activated for the following functions:
• Engine start (warm-up)
• Idle speed control
• Full load operation
• Emergency operation"

does this mean the valvetronics may have an issue?

 

She gives off no fault codes, not even when she's spluttering, apart from issues with cylinder 1 and 2, but when she's warm, switch her off and on again and even those codes disappear.

 

Questions:  

Tomorrow, they're going to change the Mapped Thermostat, at a cost of £250, but is this a good route?

Shall I suggest cleaning the breathers first? 

Would the breathers affect the engine only when cold?

 

Many thanks for all your assistance so far, to everyone.  Please keep the potential answers coming...  :) 

 

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I would reckon if was a valvtronic fault would be a complete bank throwing a fault not an individual cylinder

 

as Andrew said before the breathers prob give issue more when warmed up, mine when clogged with moisture will start smoking when warm/hot - I clean them regular and issue is reduced, I know this affects the idle too

 

the thermostat prob wouldn’t cause the issue your experiencing, maybe a long warm up if anything

 

do you know what the fault codes are? These maybe won’t be the actual fault but could go a long way to the correct solution 

 

on my e39 535the cam sensor failing gave a similar fault to your experience, and never gave a fault code either

is however 4 on the n62 engines, plus eccentric cam sensors too, all getting complicated

 

reply with fault codes, someone can maybe give some guidance

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No fault codes.  Hmm.  That's a pain

 

When mine did it it thru a fault code suggesting it was running lean i.e. an air leak which turned out to be the breather, but it took some head scratching to figure out why it was running lean.  I also had the engine warning light on in the dash.

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