Rough idle when cold. Errors when pulling trailer.

[Flyingdutchman]

BMW E53 N62 2005

Hi

More mysterious errors with my Betty. Thought I'll see if it ring a bell to someone:

1. Rough idle when cold. Hear a click sound in engine bay causing dip in engine rpm. Not AC.

No error codes set during this part. Not sure the following is related but been pulling a trailer lately:

2. Engine light blinking when pulling trailer uphill and downhill.
3. Twice engine light stayed on and whole car was shaking. Had to stop and restart the engine and all was fine again.

Kind of interesting because second part of the trip was more flat and the error didn't come back so seemed related to the hilly parts.

Errors in system, P0300 Multiple misfire, P0308 Misfire cil 8, P0307 misfire cil 7 and P0305 Misfire cil 5.

[andrewwynn]

How old are plugs? Often random misfire from dirty injectors. Techron for example.

Clicking might be Valvetronic related can your scanner view performance data realtime?

The first step to diagnose a problem with 1-2 cylinder is to swap coils with one from non neighboring cylinder.

If the problem follows the coil there's the weak link.


–awr–

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[Flyingdutchman]

Thank you for your reply. Good question, plugs are possibly quite overdue.

Was thinking since the left bank seems to misfire and problems occurs at torque variations (Pulling trailer in the hills) maybe it could be the Vanos solenoids? Could be the clicking sounds aswel. Car passed 230k miles.

[andrewwynn]

N62 not as bsd as M62 but I'm willing to bet the timing tensioners are overdue.

If the chain tension gets loose the guides can get chewed up and all hell breaks loose. One guy had the chains "chainsaw" through his block.

If you hear rattles on a cold start that fades that's often as the chain tensioner builds oil pressure. Which will take more time as the tensioner ages.


–awr–

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[andrewwynn]

Usually timing won't be off enough to misfire from lazy vanos but it's easy enough to swap bank one and two and it's usually the intake that causes the problems. Since all the plugs are likely the same age and the misfires all bank two, there is a good chance.

I would swap vanos intake banks and go up a hill with the trailer and see if you can reproduce the problem.

If the errors follow the part you've found the source.

Do you have a scanner that can monitor vanos angles? Especially helpful if it will graph them.

I've done more work on m62 than n62 but every rebuilt m62 i had problems with the cps so there's a good chance a tired CPS is at fault and that's even easier to swap.

If cps is not reporting the correct angle the engine will put the vanos in the wrong place.


–awr–

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[Flyingdutchman]

Thx again. Will investigate further and report :-)

[Flyingdutchman]

O my, Vanos valve was very dirty. Almost half the circle was filled with debree.

Quick question, saw online that when shaking the valve it should rattle if ok. Mine doesn't but I can also see a pretty firm spring inside so not sure it should rattle. What do you all say?

Or should I just put 4 new once in now I'm working on it anyway. Its done 300k miles.

[andrewwynn]

Most people will clean them. Exercise with a 9v battery while spraying with cleaner.

Overdue for chain tensioners

–awr–

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[Flyingdutchman]

Cleaned and put back.

Bought the tensioner. Can it really be removed like that? Seems very close to the chassis....

[andrewwynn]

N62 has two. Only use oem quality the knock offs are risky.

I can't find the steps in tis for chain tensioner except in sub step of bigger job like head cover job.

Look for a video on YouTube.

My "new to me" engine has about 120k miles I'm going to get a new chain tensioner for it as preventive maintenance.


–awr–

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