Page 2 of 2 FirstFirst 12
Results 26 to 37 of 37

Thread: 1998 540 throttle response not instantaneous, too much lag

  1. #26
    Join Date
    Jun 2008
    Location
    Atlanta, GA
    Posts
    4,176
    My Cars
    E53, E38, E34, E39T
    Things to check:

    Motor Mounts
    Throttle Cable
    Worn accelerator pedal linkages
    Carbon buildup on valves
    Spark Plugs
    Trans mounts





    Some Places remain unknown because no one has ventured forth. Others remain so because no one has ever come back......

  2. #27
    Join Date
    Jan 2005
    Location
    Central NJ
    Posts
    298
    My Cars
    02 540 Touring, 2010 650
    I had purchased 98 540 a few years ago for $800, because the owner at the time was told car need engine rebuilt, it was smoking at start up, had little power.

    When I got the car home, I replaced the valve behind the intake manifold. This correct the problem.

    I would suggest to check the gaskets both front and back, you don't have to remove the intake the remove these parts.

    Sent from my Pixel 3 XL using Tapatalk

  3. #28
    Join Date
    Nov 2016
    Location
    NY
    Posts
    2,665
    My Cars
    750IL/540iT/R53/E46Vert
    CSB is the Center Support Bearing on the Driveshaft - last on the list of Driveline mounts - and the most painful to change. Motor and Trans mounts are not bad. Guibo is a bit of a pain, but if he is cracked, or split, you will need to do it.

  4. #29
    Join Date
    Jan 2010
    Location
    Sonoma Whine Country
    Posts
    1,767
    My Cars
    E12, E12, E36, E39
    Quote Originally Posted by pietern740il View Post
    I had purchased 98 540 a few years ago for $800, because the owner at the time was told car need engine rebuilt, it was smoking at start up, had little power.

    When I got the car home, I replaced the valve behind the intake manifold. This correct the problem.

    I would suggest to check the gaskets both front and back, you don't have to remove the intake the remove these parts.

    Sent from my Pixel 3 XL using Tapatalk
    OK, for us I6 guys, WTF is that?
    98 328is
    02 525ita
    80 528i
    81 528ia
    and decades of owning and driving BMWs

  5. #30
    Join Date
    Oct 2016
    Location
    Atlanta
    Posts
    392
    My Cars
    2001 540iT
    Thats a crankcase vent part. The diaphragm loves to go kaplooey. You need Dooneese hands to replace it.

    Sent from my SM-G970U using Tapatalk

  6. #31
    Join Date
    May 2018
    Location
    Rockford
    Posts
    120
    My Cars
    1998 540
    I have finally gotten back to this-did some research on fuel trims and 02 sensor v/trim...confusing. MAF shows 5.15 to 5.45. Seems good, was replaced by prior owner a few yrs ago. I replaced my air intake temp unit also as it was bad. I have a K&N filter, non oiled type. Car is throwing p0170/p0173. I did just order a purge valve as that is throwing a P0443 also but I don't think that would affect running.
    02 S1 Bank 1 volts varies from .1 to .7
    02 S2 Bank 1 volts varies from .1 to .3

    02 S1 Bank 1 trim varies from -1.5 to +2
    02 S2 Bank 1 trim shows nothing

    02 S1 bank 2 volts varies from .7 to .1v
    02 S2 bank 2 volts is real stable around .1v

    02 S1 Trim Bank 2 varies from -2.4 to 0
    02 S2 trim Bank 2 shows nothing

  7. #32
    Join Date
    May 2018
    Location
    Rockford
    Posts
    120
    My Cars
    1998 540
    Update-I replaced the throttle body gaskets after a simple cigar smoke test revealed a leak at the top. Fuel mix codes are gone...

  8. #33
    Join Date
    May 2018
    Location
    Rockford
    Posts
    120
    My Cars
    1998 540
    Still doesn't have instant response like I think it should. Saw a post about the 2nd butterfly, didn't realize there was one. On a v8 is there a 2nd one, and it's a bear to get the inner throttle body off, can't remember now when the outer one comes off, is the butterfly in that, or in the inner portion?

    Is there a 2nd butterfly?

  9. #34
    Join Date
    Apr 2016
    Location
    the great pacific n.w.
    Posts
    1,216
    My Cars
    540it, 540sedan, 540-6 s
    The second butterfly or throttle plate is in front of the main throttle. It is normally open and is only closed by the asc or traction control system.
    Not likely to be involved in any way to your problem.
    Vacuum leaks, followed by a dirty throttle position sensor would be my guess.
    Then fuel pump pressure, vacuum leak to the fuel regulator, (also a pressure related thing), then you are getting down to small stuff.
    Is it just your perception? Test drive another 97-8.

  10. #35
    Join Date
    May 2018
    Location
    Rockford
    Posts
    120
    My Cars
    1998 540
    I did clean the TPS, did wonder about the fuel pump pressure, or vac leak. I need to check that...I've literally never seen another 540-8...I live in MI. Mine was stored, maybe they all rusted out, but they're not seen around these parts. Thanks for the tip. The fact that the car idles low and has an audible stumble at idle, and as it gets colder, it'll be some worse, are all symptoms that I can't figure out. Will try the fuel issue. I did suspect a pressure sensor issue also...

  11. #36
    Join Date
    Dec 2006
    Location
    West of Boston, MA
    Posts
    726
    My Cars
    2001 BMW 540iT/6
    Vacuum leak would get worse when cold.


    Sent from my iPhone using Tapatalk

  12. #37
    Join Date
    May 2018
    Location
    Rockford
    Posts
    120
    My Cars
    1998 540
    Checked on the tubing at the fuel pressure reg, seemed good. Couldn't do my custom cigar smoke test (lol), no cigars! May remove the PVC if I get time and see how that all looks.

Page 2 of 2 FirstFirst 12

Similar Threads

  1. 1998 540 v8 - Not as responsive as I'd like
    By Eriklane in forum 1996 - 2003 (E39)
    Replies: 22
    Last Post: 04-12-2019, 08:30 PM
  2. Replies: 18
    Last Post: 08-23-2016, 09:04 PM
  3. 1998 m3 throttle not working
    By capnhook in forum 1992 - 1999 M3 (E36)
    Replies: 7
    Last Post: 09-14-2009, 09:34 PM
  4. Throttle Body not responsing 100%
    By MitEclipse3G in forum 1999 - 2006 (E46)
    Replies: 1
    Last Post: 03-23-2009, 01:16 AM
  5. Increasing Throttle Response on a 540
    By gsibble in forum 1988 - 1996 (E34)
    Replies: 15
    Last Post: 07-20-2005, 02:33 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •