Page 2 of 4 FirstFirst 1234 LastLast
Results 26 to 50 of 90

Thread: 745i: No boost at all :-(

  1. #26
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Quote Originally Posted by timgal1234 View Post
    If you put a plate over the hole where the wastegate bolts down you are not going to do anything but seal the exhaust leak the valve must be seated inside the manifold to keep exhaust from bypassing the turbo hotside when the valve is pushed/pulled up it allows the exhaust to bypass turbo hotside thereby reducing boost. Blocking off the hole at the top of the manifold leaves the bypass passage wide open.

    Thanks a lot you for your help, but I did not understand everything ....I placed the plate here:
    wastegate.jpg
    Last edited by gigi; 10-08-2017 at 04:17 AM.

  2. #27
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello,
    Some tests doing this week-end with refurbished turbo, free exhaust and closed wastegate....
    The same thing, no boost...
    I don't anderstand anything...

  3. #28
    Join Date
    Dec 2012
    Location
    topanga CA
    Posts
    483
    My Cars
    84 728i,325Ci, 77 R100RS
    Have you got the turbo mounting clearance correct? If it's too far out the boost will drop off radically.

  4. #29
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Quote Originally Posted by andyleonard View Post
    Have you got the turbo mounting clearance correct? If it's too far out the boost will drop off radically.
    You mean the turbo shaft play? Axial and radial ?

  5. #30
    Join Date
    Dec 2012
    Location
    topanga CA
    Posts
    483
    My Cars
    84 728i,325Ci, 77 R100RS
    No. Mounting clearance of assembled turbo into clamp.

  6. #31
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Quote Originally Posted by andyleonard View Post
    No. Mounting clearance of assembled turbo into clamp.
    Sorry I don't understand...which clamp ?

  7. #32
    Join Date
    Dec 2012
    Location
    topanga CA
    Posts
    483
    My Cars
    84 728i,325Ci, 77 R100RS
    Have you checked the impeller to case clearances in the turbo? I rebuilt one and set the clearance too high and it lost half the boost.

  8. #33
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello,
    No I doesn't check this....but...it is not possible to adjust this clearance, isn't it ?

  9. #34
    Join Date
    Dec 2012
    Location
    topanga CA
    Posts
    483
    My Cars
    84 728i,325Ci, 77 R100RS
    http://forums.pelicanparts.com/911-9...o-rebuild.html

    Scroll down in this article and see some of the links from turbo shops. A couple of them have troubleshooting sections.

    You sound like a smart guy and you're doing everything right. There has to be something wrong with the turbo itself for your application.

    QUESTION: Have you ever driven this car successfully with this turbo installed? Is it possible it's the wrong turbo for the car or that it has the wrong parts inside?

  10. #35
    Join Date
    Jun 2010
    Location
    TX
    Posts
    4,487
    My Cars
    1983/84/85 745i

    Thumbs up

    What is your hot idle air fuel ratio on the wideband? Spec is around 800rpm and 13.7-14.2:1

    What rear differential is in this car?

    Check for continuity of throttle switch. Pins 1 and 2 should make circuit at idle from memory. Pins 2 and 3 at wide open. Hell, does the throttle even open 100%?

    What ECU? Early Ljet is -124, should be until 09/81. From 09/81 to 05/83 is the -127 ECU.
    I make E23 parts.
    09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
    10/1984 745i
    11/1984 745i
    11/1984 735i (10:1-265/6)
    Ford, MB, and GM round out the pack.



  11. #36
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello all :-)

    @ andyleonard, I looked at the links of of the article you quoted, and find troubleshooting sections, thanks a lot, but no results after differents testing.

    @ Hit Man X, My fuel ratio at idle is a little lean, approximatly 15.5-16:1.
    But 13.7-14.2:1 is quit rich, no? Normally it's musn't be 14.7:1?

    Diff is 3.25 open, but what is the relationship with boost?

    Continuity at throttle switch is ok, 3 pins are numbered 2 - 18 - 3.
    2 and 18 make circuit at idle, and 18 and 3 at WOT (and yes throttle open 100% ;-) )

    The ECU is 0230001124 (the car was made in 05/81)


    Thanks a lot for your help ;-)
    Last edited by gigi; 11-05-2017 at 02:44 PM.

  12. #37
    Join Date
    Jun 2010
    Location
    TX
    Posts
    4,487
    My Cars
    1983/84/85 745i
    Factory spec is 0.5-2% CO at idle. That is 13.7-14.2:1 with a wideband.

    Car has no ECU O2 sensor feeback, it will never achieve 14.7:1 which is an emission number. Tune car for 14:1 hot idle

    It will cruise off boost in mid 15s. TOTALLY NORMAL. Full power should be mid 12s.
    I make E23 parts.
    09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
    10/1984 745i
    11/1984 745i
    11/1984 735i (10:1-265/6)
    Ford, MB, and GM round out the pack.



  13. #38
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello :-)

    Thanks a lot :-)

    OK, so I have to adjust AFR richer.
    Do you think I can tune it with the AFM bypass screw or I have to adjust the AFM spring wheel?
    AFM_picture.jpg hqdefault.jpg

  14. #39
    Join Date
    Dec 2012
    Location
    topanga CA
    Posts
    483
    My Cars
    84 728i,325Ci, 77 R100RS
    Try a couple of clicks on the spring wheel if you want to change the entire mixture range. Then try tuning the idle with the allen screw. At some point the AFM screw won't lean out any further.

    If you are careful, you can tune further by loosening the little set screw and moving the pointer arm. Be very careful to mark everything where it is now as you will make yourself crazy if you lose the base settings.

    Unfortunately I don't think this fine mixture tuning is keeping your turbo from boosting.

  15. #40
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Ok thanks a lot.

    I'll try this in few days because now I have changed entire engine, this time it is a M106 motronic...but currently I'm very unlucky because this engine don't start at all...no spark and no injection.
    I will received 2 news crankshaft position sensors this week, and I hope this is the cause of the problem...

    Thanks

  16. #41
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello!
    Some (good) news!
    I replaced the 2 crankshaft position sensors on the bellhousing and the M106 start! :-)
    So now I have to test it on road....but a lot of snow now...I have to wait...
    :-)

  17. #42
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello!

    Some news...
    I drove the car on track this week end, with the M106 engine...and the problem is still here!
    No boost!
    I don't understand anything :-(

  18. #43
    Join Date
    Mar 2004
    Location
    las vegas
    Posts
    338
    My Cars
    85 745
    Quote Originally Posted by gigi View Post
    Hello!

    Some news...
    I drove the car on track this week end, with the M106 engine...and the problem is still here!
    No boost!
    I don't understand anything :-(
    Where are you located? It looks like you been chasing the same problem for some time now.

    Email me at devin1205@gmail.com

  19. #44
    Join Date
    Oct 2007
    Location
    Valley Village, CA
    Posts
    624
    My Cars
    1985 745i
    Quote Originally Posted by gigi View Post
    Hello!

    Some news...
    I drove the car on track this week end, with the M106 engine...and the problem is still here!
    No boost!
    I don't understand anything :-(
    Are you running Motronic from the m106 as well?


    Sent from my iPhone using Tapatalk
    When your enemy is making a mistake, do not interrupt him.

  20. #45
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Yes, motronic with knock box.
    The engine start well, idle is good, no smoke or suspect noise....
    But the boost gauge never exceed 0 bar...
    And at idle, boost gauge indicate approximately -0.6 bar, it seems good...

  21. #46
    Join Date
    Jun 2010
    Location
    TX
    Posts
    4,487
    My Cars
    1983/84/85 745i

    Thumbs up

    You have a boost leak or exhaust leak somewhere probably. I guess your wastegate may not be seated correctly and the valve is off the seat bleeding exhaust off. Even a Motronic wastegate with direct signal will make about 0.1 bar of boost. The system requires the boost solenoid to work correctly.

    LJ had this issue once, turbocharger was bad. The CHRA had seized and snapped the shaft...he swore up and down it could not be that as the compressor wheel spun fine. I made him drop the exhaust and hold the compressor wheel stationary while trying to spin the turbine wheel. Guess what? He was able to do that. Swapped K27s and off the car went.
    I make E23 parts.
    09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
    10/1984 745i
    11/1984 745i
    11/1984 735i (10:1-265/6)
    Ford, MB, and GM round out the pack.



  22. #47
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello!

    I have installed the LJ Wastegate...without boost solenoid to simplify the system and avoid the causes of additional breakdowns...
    I have used the metalic pipe to connect turbocharger to wastegate directly, like LJ
    Turbocharger shaft is not broken, I rebuilt it with new parts and it turn freely

  23. #48
    Join Date
    Jan 2012
    Location
    Vancouver, BC Canada
    Posts
    94
    My Cars
    1985 Mercedes 300SD
    Have you confirmed that your boost gauge works?

  24. #49
    Join Date
    Dec 2012
    Location
    topanga CA
    Posts
    483
    My Cars
    84 728i,325Ci, 77 R100RS
    Quote Originally Posted by dude99 View Post
    Have you confirmed that your boost gauge works?
    And where is it connected?

  25. #50
    Join Date
    Mar 2009
    Location
    fr
    Posts
    54
    My Cars
    e9,e28,e30,e36 and e46
    Hello!
    Boost gauge works (I'll post some pictures tomorrow...) And it is connected underside the intake manifold

Page 2 of 4 FirstFirst 1234 LastLast

Similar Threads

  1. Oxygen sensor or no snesor at all.
    By BIMMERBOYZ in forum 1983 - 1991 (E30)
    Replies: 19
    Last Post: 01-12-2007, 03:52 AM
  2. I'm tellin ya, no respect at all!
    By Jetter2 in forum 1983 - 1991 (E30)
    Replies: 128
    Last Post: 06-28-2006, 03:16 PM
  3. No electrical at all - Cars dead
    By 99FiveFortyMike in forum 1988 - 1996 (E34)
    Replies: 2
    Last Post: 01-18-2006, 06:25 PM
  4. No Sound At All!
    By ///MDriver in forum Car Audio & Electronics sponsored by Bavsound
    Replies: 6
    Last Post: 04-15-2003, 06:14 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
  •