e39 540i low down power loss

[tangalife 1]

Hi guys,

I have noticed of a power loss between 2-3.5k RPM. When accelerating there seems to be a lack of power but appears to pick up and go after 3.5k RPM. Is the same when I put my foot right down as well. It seems like my fuel consumption has gone up and, not sure if I've only just noticed now, but you can perhaps smell fuel when idling (at least when the car is warming up).

Has anyone had similar problems?

1997 e39 540i automatic.

[yng_750 247]

just something to quickly check is the Crank case vent valve.

if they die it sucks air out of the engine, bypassing the airflow meter.

easy to check. if its broken it will create a large vacuum in the engine.

try to open the oil cap when its running, large vacuum will stop you lifting it up, or as i did pull out the dipstick while it running, you would hear loud sucking/gurgling if its damaged.

good place to start

[tangalife 1]

thanks for that will give it a go.

failing that, I might try disconnect the o2 sensor as similar problems ive searched online suggest bad pre cat o2 sensor. Is it safe to just disconnect the o2 sensor to go for a test drive? Or am I best to just straight replace them?

[tangalife 1]

just something to quickly check is the Crank case vent valve.

if they die it sucks air out of the engine, bypassing the airflow meter.

easy to check. if its broken it will create a large vacuum in the engine.

try to open the oil cap when its running, large vacuum will stop you lifting it up, or as i did pull out the dipstick while it running, you would hear loud sucking/gurgling if its damaged.

good place to start

seems to be exactly this. just took it for a drive, appeared to be sluggish when cold which I understand rules out the o2 sensor as when faulty it will behave normal while cold but not when warmed up.

I pulled out the dipstick and could hear gurgling and sucking. Took oil cap off, it was easy to take off but you could hear air and it spat oil out.

[yng_750 247]

yea very common issue in these cars unfortunately when they start sucking oil even small amounts it kills o2 sensors and plugs so people often spend money they dont need to after reading the codes.

i just did mine without too much issue

its the whole rear cover on the intake manifold.

very much a part you need to get OEM, aftermarket almost always warp and fail.

will cost around $190 from the dealership for cover and gasket.

part numbers are 11-61-1-729-728 for gasket

and 11-61-7-501-563 for rear cover.

check out

and

fairly in depth.

if you dont think its something you can do id say give botany motor worx a call they should be able to give you a price

http://www.botanymotorworx.co.nz/index.html

if your car isnt smoking at start up yet id say you can still drive it but to save spending heaps of money on plugs and o2 sensors your better to get it done sooner rather than later.

but yea any other questions feel free to ask, i literally finished doing mine 5 mins ago

[BM WORLD 1265]

also a bad air flow meter , have new ones if you want to try one.

[tangalife 1]

Thanks for the help Jason H, much appreciated

Wonder if I should change the AFM first, or just do both as preventive anyway? Lucky i still have my old run about so I can park the Bimmer up for the time being.

Edited January 27, 2013 by tangalife

[yng_750 247]

id say still do the ccv first

you know for certain that its ripped the diaphram inside, all it can do is get worse.

fix that then see how it runs

AFM is very easy to swap but alot of money if its not broken

[tangalife 1]

K ive noticed two things:

first - not sure if its sopose to - but the ICV is emitting a loud beeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeep noise when the key is switched to on position. I can only assume that it is a normal noise. Going to give the ICV a clean out tommorow

Also this loud whistling noise when the car is running: www.youtube.com/watch?v=ABi8lgL-SJY.

Could it be the valve cover gasket? The prev owner changed tensioners so might not have put back on properly?

Edited January 31, 2013 by tangalife

[Eagle 1537]

Buzz is normal. Id say do ccv valve first as well since it sounds like its bad, check for any vacuum leaks and get it scanned it. If any of that doesn't fix or id the problem then you can start swapping parts like afm etc to find the issue

[tangalife 1]

Buzz is normal. Id say do ccv valve first as well since it sounds like its bad, check for any vacuum leaks and get it scanned it. If any of that doesn't fix or id the problem then you can start swapping parts like afm etc to find the issue

Cool. I did the oildipstick test, no sucking when I put my thumb over.... Going to try a vaccum leak tommorow as the prev owner replaced tensioners perhaps and left a leak when putting it back togeather.

[tangalife 1]

txted the old owner today, he reckons he changed the ccv so its fairly new. might try change fuel filter. icv was clean as well.

[Jono51 58]

txted the old owner today, he reckons he changed the ccv so its fairly new. might try change fuel filter. icv was clean as well.

sort the vacuum leaks, but get it scanned and live data

if you keep unplugging things , 02 sensors, afm, etc whilst running , thinking that you will rule them out, will in fact log fault codes, so when it is scanned you will have a whole host of fault codes that will lead you in the wrong direction,

assuming you are in auckland I suggest you talk to Glenn