BMW Forums : BimmerForums banner

1 - 20 of 38 Posts

·
Registered
Joined
·
60 Posts
Discussion Starter #1
Hi guys, ive recently purchased a 525d with 114k on the clock. the problem is when the car is at a low rev (mainly only in 4th gear) and i put my foot down the turbo sounds like its missing(fluttering type of sound), im not that clued up about turbos but it sounds very much like the wastegate is opening and closing very very fast. It picks up fine in gears 1-2 but i have noticed this problem in 3rd and 4th as its very flat in accelerating.

diagnosis showed code 1470 charge-air pressure control and 3505 glow plug system

to date i have done the following:

castrol edge 5w30
replace engine breather with standard loo roll type
fuel filter
air filter
cabin filters

and for this particular problem i have done the following:

changed MAP sensor (behind inlet manifold)
upgraded the vacuum pipes
checked the boost hoses
driven with the MAF disconnected also cleaned MAF with isoproply

its still behaving no differently, im running out of ideas, someone please help!
 

·
Registered
Joined
·
7,043 Posts
It could be item no.1, the pressure converter, this can swapped with the pressure converter that controls the EGR valve,also item no.1 in pic below.
IMO you need to confirm the turbo actuator arm is moving sufficiently when boosting if not it could be loss or lack insufficient vacuum
from a leak on the vacuum piping, cracked/split vacuum reservoir, faulty pressure converter or even turbo issue :frown

Image taken from RealOEM page..http://www.realoem.com/bmw/showparts.do?model=DL92&mospid=47540&btnr=11_2336&hg=11&fg=45
 

·
Registered
Joined
·
60 Posts
Discussion Starter #4
thanks mate, if the pressure converter is faulty and i swap them over will it be ok to drive the car just to test whether the swap has cured it?

is there any way of checking the actuator as i cant even see it??

thanks for your help!
 

·
Registered
Joined
·
7,043 Posts
thanks mate, if the pressure converter is faulty and i swap them over will it be ok to drive the car just to test whether the swap has cured it?
If you swap the PC's over the faulty one will operate the EGR valve, or not as the case may be, and the boost on the Turbo should operate as it should.

is there any way of checking the actuator as i cant even see it??
Can't you view the Turbo and its actuator by removing the plastic engine covers and peering down the drivers side of engine?
 

·
Registered
Joined
·
60 Posts
Discussion Starter #6
nice one mate, ill swap them over tomorrow, any tips on how i can check to see if the actuator is operating as it should?
 

·
Registered
Joined
·
7,043 Posts
any tips on how i can check to see if the actuator is operating as it should?
afaik movement should be linear and even without stuttering or sticking.
Also check the actuator arm is secured to the linkage as I've heard of these coming loose and slipping which reduces the travel. :thumbsup
 

·
Registered
Joined
·
60 Posts
Discussion Starter #8
hi guys, today i changed the pressure converter for a new one and fitted a new vacuum tank but with no joy, really started to get annoyed now!

i will check the actuator tomorrow, funny thing is that in first and second the car is pulling very well.

one thing i did notice today though, when im driving hard, there was a momentary sudden loss in power for a split second and all of a sudden it was ok, it happened on 2 occassions, could this be related?

i also had the diagnostic done again after fitting the new parts and im not getting any faults logged now.

any more insight would be very helpful at this point!
 

·
Registered
Joined
·
60 Posts
Discussion Starter #9
just to when i serviced the car (around 3 weeks ago) i did add wynn's stop smoke treatment to the oil, could this be having a negative effecto n the turbo?
 

·
Registered
Joined
·
1,482 Posts
just to when i serviced the car (around 3 weeks ago) i did add wynn's stop smoke treatment to the oil, could this be having a negative effecto n the turbo?
Mate these engines don't need any additives add in them I personally would have that drained out, put some good quality engine oil in it and change the oil filter also
 

·
Registered
Joined
·
7,043 Posts
hi guys, today i changed the pressure converter for a new one and fitted a new vacuum tank but with no joy, really started to get annoyed now!
Commendable but an expensive method of fault finding :frown

i will check the actuator tomorrow, funny thing is that in first and second the car is pulling very well.

one thing i did notice today though, when im driving hard, there was a momentary sudden loss in power for a split second and all of a sudden it was ok, it happened on 2 occassions, could this be related?

i also had the diagnostic done again after fitting the new parts and im not getting any faults logged now.

any more insight would be very helpful at this point!
Sounds like it could be the MAF, hesitancy in power and flat spot? cleaning them is never a permanent solution but I don't suggest you buy a new one simply on a guess.

Local Diesel specialists may have the equipment to check the MAFs function, especially the Bosch specialists as the MAF is a Bosch unit.

I'd still check the movement on the turbo actuator arm as mentioned earlier and try driving the car again with the MAF disconnected
to see if the hesitancy disappears?

good news on the lack of error codes tho, a step in the right direction :thumbsup
 

·
Registered
Joined
·
60 Posts
Discussion Starter #12
hi mate, i tried to clean my egr valve but it wouldnt budge so i sprayed the thing with isopropyl and wiped it down as much as i could.

I poped in a new maf, it was the cheapo one from ecp just to see whether the problem goes or is still there, i did a breif run around the block the hesistancy was still there and then i took it back to the mechanic for a diagnostic and it show a MAF error, put the old bosch one back in and the error was gone. do these maf's need to be coded to the car??

i checked the actuator arm today aswel, it does seem to be functioning however, it does seem to get stuck in the closed position after i let go of the gas and doesnt go back to the top!

also, i removed the vac pipe going to the turbo and the car was slow as hell but there was no hesitation and it was smooth

im really not sure now, im swaying towards a new actuator arm if these are even available?!

im not sure if you guys would know, but i have used 4mm vac hose and on real oem it states bmw use a 3.5mm hose would this make much difference??

thanks for all the help guys!
 

·
Registered
Joined
·
7,043 Posts
You won't budge the EGR in situ as it needs some force to open it!

Your MAF should be a Bosch 0928400468 and so the replacement is 0928400527 no programming required, the number should be on the side of the housing.

The sticking actuator arm may account for the hesitancy and no I don't think you can buy them separately :frown

In theory a 4mm vacuum pipe could leak, GSF sell the correct size @£2/metre, ebay too, or dealers @£10/metre!

this member recently released a sticking actuator arm http://www.bimmerforums.co.uk/forum/f18/2003-e46-320d-auto-touring-black-smoke-and-t96151/ hope its not the variable vanes that are sticking with carbon!
 

·
Registered
Joined
·
60 Posts
Discussion Starter #15
Hi guys I popped a new bosch maf into the old maf housing as I couldn't remove the old housing and ran a diagnostic and I received a maf error, is it necessary to change the maf housing that comes with the new sensor or do I have another duff sensor?as my old sensor doesn't produce any faults!
 

·
Registered
Joined
·
7,043 Posts
Hi guys I popped a new bosch maf into the old maf housing as I couldn't remove the old housing and ran a diagnostic and I received a maf error, is it necessary to change the maf housing that comes with the new sensor or do I have another duff sensor?as my old sensor doesn't produce any faults!
It is generally recommended to replace both sensor and housing, where did you source the sensor only?
and what MAF error code number and description are you reading?
 

·
Registered
Joined
·
60 Posts
Discussion Starter #17
Hey mate,I got the maf with the housing but decided just to swap the maf sensor only.I can't remember the error code it gave though :(. Does the maf need coding?
 

·
Registered
Joined
·
318 Posts
turbo is probably seizing up, take the pipe off the front of it and feel the impeller, it should be very easy to turn with no "play" in it.
 

·
Registered
Joined
·
60 Posts
Discussion Starter #19 (Edited)
Aparantly the turbo is over boosting according to the mechanic who examined it today:

'a fault was found in the following assembly:- boost pressure adjuster/turbocharger. the boost pressure detected was too high'
check the following causes for faults -
pressure converter defective
actuation of pressure converter defective
vacuum supply defective
boost pressure adjuster moves too stiffly
turbo charger defective

these are the faults the ecu picked up on
 
1 - 20 of 38 Posts
Top