Jump to content

BMW 5 Series Owners Board uses cookies. Read the Privacy Policy for more info. To remove this message, please click the button to the right:    I accept the use of cookies

Thank you for visiting bmw5. If you'd like to show your support for the forum, please consider becoming a Gold Member


Photo
- - - - -

2002 525i hesitation when pulling away...any ideas anyone?


  • Please log in to reply
42 replies to this topic

#31 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 26 September 2010 - 06:55 PM

i should have included in my previous post that i took the hose off, blew through it and didnt hear any oil bubbling so if all is to be believed i have a split hose

#32 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 02 November 2010 - 02:42 PM

just to put this thread to bed now.....

After changing ccv and associated pipes, replaced a split blanking plug at the rear of the intake manifold, replaced o-ring around dipstick etc etc oil can now be heard bubbling when blowing through the top hose.

Also ever since i did that work i notced that when the car was stone cold if i pulled away then took my foot off the accelerator it would still move forward and just decrease speed steadily, before when i tried this the bloody car would near enough stand on its nose as if i had pressed the brakes so the car definetly benefitted from the new parts.

Only thing was i was still getting the occasional rev dropping and stalling when reversing so at the weekend there i pulled the idle control valve off, filled it with machine cleaner and thoroughly cleaned it, previously when it was off it seemed to move freely but actually this time after cleaning you can hear it clicking as you twist it and hey presto, it seems to have done the trick! Early days yet but im confident the car is at full health again.


Only one thing left to do now, when i turn a corner i can hear something rolling around behind the drivers seat i think. Iv had the carpet out, the door panel off and cant find nothing, also put a hoover nozzle up the heater vents under the seat but still no joy...any of you guys got an idea or had the same really annoying thing?

#33 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 11 December 2011 - 09:57 PM

Well....just to dig up this old thread, the hesitation thing never did go away after all and its really starting to bug me now. Seems to have gotten worse in the colder weather so i think tomorrow i shall pull everything apart and double check for any source of an air leak. Does anyone know what i could check on my bmw software package which would point towards an air leak in the intake pipework?

#34 viran_e39

viran_e39
  • LocationNW London
  • Current Car:2000 528i Sport

Posted 11 December 2011 - 11:23 PM

I bought my car with the engine management light on, it had a rough idle and would also hesitate when moving off. I noticed a loud hissing sound from the engine bay which lead me to believe it would be a vacuum leak somewhere, hence why i bought it. I found that the rubber boot going into the throttle body has another pipe going off it had perished (i think it leads up to the idle control valve). But im guessing here - if you had that problem your car may have been alot worse and throw up countless errors linked with improper burn across your cylinders and dodgy lambda readings. but worth a shot anyway mate. mines a 2000 528i by the way m52tu

Posted Image

#35 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 11 December 2011 - 11:50 PM

That wasn't too hard to diagnose eh! lol

I have previously checked all the pipework and changed the ccv, cleaned the idle control valve, ensured the DISA valve is tightly sealed etc etc. I even had the inlet manifold gasket changed. I think its a very slight air leak somewhere as it never flings a code, its not even a major prob but its now starting to annoy me.
Ideally i need someone with a bit of inpa knowledge to tell me what values i should be checking that would indicate a leak.....

#36 alpinaman

alpinaman
  • LocationHigh Peak

Posted 12 December 2011 - 07:22 AM

What about lambda control and AFM readings..?

Have they been checked ?

Understeer is when you hit the wall with the front of the car. Oversteer is when you hit the wall with the back of the car. Horsepower is how fast you hit the wall and torque is how far you send the wall across the field once youve hit it.


#37 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 12 December 2011 - 02:45 PM

I've never had these readings checked (by anyone other than me that is, and i dont know what im looking for lol) but i will pop out just now and plug in the laptop then report back my findings. This morning i went out and stripped out the airbox and checked the hoses for perishing and splits, couldn't see anything wrong, and i've now put everything back together ensuring its properly sealed. Even sprayed highly flammable propellant around the whole inlet area to see if i could get the revs to rise but no, nothing.

Its either me being too hyper sensitive or its a fault elsewhere so i'll go and take a note of all the readings and post them up

cheers alpinaman

#38 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 13 December 2011 - 07:20 PM

Righto, i plugged in the laptop earlier today and took a look at the engines analogue readings.

engine @ 750rpm, about a minute after being started from stone cold, temp needle sitting just off the blue.

Total air consumption; 13.5kg/h
lambda probe before catalyst bank 1; 0.32V lambda probe after catalyst bank 1; 0.78V
lambda probe before catalyst bank 2; 0.73V lambda probe after catalyst bank 2; 0.72V

TV probe heating before kat bank 1; 99.31% TV probe heating before bank 2; 99.31%
TV probe heating after kat bank 1; 99.31% TV probe heating after kat bank 2; 99.31%

Does this seem normal for an M54 2.5?

Anything else i need to be checking the readings of on inpa?

Edited by jamesno1, 13 December 2011 - 07:21 PM.


#39 sixspeed

sixspeed
  • LocationHampshire
  • Occupation:Highway design
  • Current Car:540i/6

Posted 14 December 2011 - 01:00 AM

Your symptoms sound familiar to me (although mine is a V8). It was only a minor complaint, and for ages I couldn't figure it out and just lived with it. Then one day my airflow mass meter packed up big style. When I replaced it the difficulty pulling away was gone, it felt brilliant! I concluded that it must had been slightly off since I got the car, just not enough to flag an error.

It's not cheap enough to take a punt on, but if you've tried everything else it might be worth it.
Posted Image
540i Touring manual (with LPG conversion)

#40 viran_e39

viran_e39
  • LocationNW London
  • Current Car:2000 528i Sport

Posted 14 December 2011 - 10:40 AM

Your symptoms sound familiar to me (although mine is a V8). It was only a minor complaint, and for ages I couldn't figure it out and just lived with it. Then one day my airflow mass meter packed up big style. When I replaced it the difficulty pulling away was gone, it felt brilliant! I concluded that it must had been slightly off since I got the car, just not enough to flag an error.

It's not cheap enough to take a punt on, but if you've tried everything else it might be worth it.


OP, you could try give it a clean rather then replace it, see if it helps?

http://www.powerenha...-sensor-cleaner

#41 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 14 December 2011 - 03:55 PM

The other day when i pulled all the airbox and pipework out to re-check, I sprayed the MAF with electrical contact cleaner and very VERY gently used a cotton bud to ensure it was clean/dry. I was actually going to go to a scrapyard and buy one but they wanted £25 and to be honest it could be in the exact same state as mine so i didnt see the point in wasting the £25.

Looking at the figures i posted above, the pre-cat lambda sensor in bank 1 is different to the other 3 by a fair margin so i wonder if that may have something to do with it. This is the trouble with these things, i don't have any experience electrical fault finding so i don't know whether i'm pissing into the wind. And these days money is an issue so i can't afford to fling new parts at it willy nilly........ah the joys eh

#42 jamesno1

jamesno1
  • LocationGlasgow
  • Occupation:Engineer
  • Current Car:w204 mb c320 cdi

Posted 15 December 2011 - 08:49 PM

Any technical whizzes out there??

#43 gar525i

gar525i
  • Locationireland
  • Current Car:bmw 525i

Posted 18 December 2011 - 10:02 PM

id strongly recommend taking the cdv out as mentioned earlier, i picked up a 525i 6 months ago and couldn't get a decent take off or a correct shift between 1st and 2nd i felt like a learner when taking off it was getting embarrising and annoying , it will cost you nothing to remove it just half an hour of you time the difference to me was like night and day http://www.zeckhausen.com/cdv.htm
in 1996. BMW introduced the E39 .The car designed by Joji Nagashima, inventor and designer born (1955.) in Tokyo and educated in the US, employee of BMW since 1988. Because of its timeless design and superb engines performance, the model was known as 'the best sedan ever made. In 2001 a facelift was done, and since then E39 became a timeless ultimate driving machine with true fans all over the world.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users