Results 1 to 14 of 14

Thread: 98 750IL running on one bank

  1. #1
    Join Date
    Nov 2018
    Location
    Virginia
    Posts
    35
    My Cars
    1998 750IL

    98 750IL running on one bank

    Ok guys, lets see who has some ideas on this. 1998 750 IL, V12 of course, 162,000K miles. Ive been driving it for about 8 months. Never had any issues, always started right up and ran like a top. Last November I returned home from a 4 hour trip, parked her in the driveway and retired for the night. I then went to start her the next morning, nothing, no crank, no start. Had the common symptoms, had power, lights, dash, etc.. but no crank. So after researching here and checking everything I could at home, off to my local BMW indie for help. This was in the December time frame.
    Indie then left for a church mission trip and the car sat at his place until end of January. After his diagnostics he determined failed EWS module, and now, of course, dead battery. He ordered a replacement EWS and installed it and a new battery as the other one was quite old.
    Now the odd parts start.... His software at this time would only show one DME. Bear in mind guys I am just relating what was communicated to me. Also, his software would not let him establish and link the EWS to the DME/car. The car would now spin over, but not start. He had another guy close by that used to work on older BMW's and had more diagnostics and software than he did, so off to the other guy on the wrecker my car went.
    So a week ago, I get the call that the EWS is linked, the car starts and runs. Joyed that my car is ready, off to pick her up I go. When I get there the place is very busy and I grab the indie for a moment to ask him if everything is good before I leave. He says yes, she starts and cranks, but.... seems to be low on power, doesn't run like a V12 should. He determined this when he picked my car up from the other guy and drove it back to his shop. His reasoning was maybe since it sat for a few months, it could be old gas. Or maybe, it could be a clogged cat, resonator or muffler, and I had asked him to get it running, not to figure out the low power thing now. He said maybe its something to do with his software only showing the one DME, and the other guy he took it to said the same thing, and he had to dig back to some older BMW software he had to get the EWS to link, because all the newest versions he had wouldn't allow it to link.
    SO I said OK I'm taking and off I go.... DANG!!! WEAK WEAK WEAK.... wont hardly pull a small incline.... mash the pedal down and it takes forever to pick up speed! I stop at a gas station as I had between 1/4 and 1/2 tank, and filled up with premium. SO I finally get it home, about a 30 mile drive, and just park it for the night and do some research here.
    The next morning I started her up, sounded dead, let here warm up a few minutes then hit the down tubes of the manifold with my IR gun, right bank about 300 degrees and climbing, left bank, 80 degrees. More research....
    So now at this point, below is listed what I have done, and its still dead on the left bank. Before I take it to the dealership, I was hoping for some ideas here to try that I haven't. Thanks guys for any help.
    So far to date:
    • Cleaned both MAF
    • Checked all fuses, under hood, trunk and pass floorboard, all good, none blown
    • Swapped MAF's to different sides
    • Unplugged TB's cleaned connectors
    • Pulled distributors, all contacts and rotors looked good, swapped rotor buttons side/side
    • Pulled off left rear plug wire, inserted a spare plug, grounded while starting, no spark
    • Unplugged MAF's while running, left side stalled engine, right side no change in engine
    • Unplugged TB's while running, left side stalled engine, right side no change in engine
    • Unplugged and inspected coil wires, nothing odd seen
    • Pulled left MAF/airbox cover off while running, stalled engine
    • Pulled right MAF/airbox cover while running. no change in engine

    So that's where I'm at now. She will start and run, but just on the right bank. So I'm open to all ideas!!

  2. #2
    Join Date
    Jan 2017
    Location
    nj
    Posts
    55
    My Cars
    2001 740i Sport
    check the main fuses in the dme box

  3. #3
    Join Date
    Nov 2018
    Location
    Virginia
    Posts
    35
    My Cars
    1998 750IL
    I have checked all the fuses with a meter... including the engine control fuses in the under hood fuse panel where the DMEs are located.... all were good.

  4. #4
    Join Date
    Feb 2009
    Location
    KC North, MO, USA
    Posts
    11,153
    My Cars
    1996 740iL
    I'm not a V12 guy but I would start by swapping coils to see if it changes which side is dead. There is also a procedure to calibrate the TB's that has worked for some in this case. I'm told it often takes several tries for it to work.

    1. Turn ignition to position 2, wait 3-5 seconds
    2. Push the throttle pedal all the way down and activate kick down switch, hold it for 3-5 seconds
    3. Let off the pedal completely, wait 3-5 seconds
    4. Push the throttle pedal all the way down and activate kick down switch, hold it for 3-5 seconds
    5. Let off the pedal completely, wait 3-5 seconds
    6. Turn off ignition, wait at least 10 seconds.

  5. #5
    Join Date
    Dec 2016
    Location
    Springfield, VA
    Posts
    1,005
    My Cars
    2001 750iL DD74441
    Check your relays for the DMEs
    https://www.newtis.info/tisv2/a/en/e...il-lim/UrzaiZ0

    Sounds like the DME isn’t getting power so check the connections etc.
    also one is a “slave” and the other the “master”. Not likely but if pulled and switched it can cause issues. Might try a swap.



    2001 750iL DD74441
    Stock

    RIP: 2003 540iA Sport GS56111
    H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

  6. #6
    Join Date
    Nov 2018
    Location
    Virginia
    Posts
    35
    My Cars
    1998 750IL
    Quote Originally Posted by Mayorchuck View Post
    I'm not a V12 guy but I would start by swapping coils to see if it changes which side is dead. There is also a procedure to calibrate the TB's that has worked for some in this case. I'm told it often takes several tries for it to work.

    1. Turn ignition to position 2, wait 3-5 seconds
    2. Push the throttle pedal all the way down and activate kick down switch, hold it for 3-5 seconds
    3. Let off the pedal completely, wait 3-5 seconds
    4. Push the throttle pedal all the way down and activate kick down switch, hold it for 3-5 seconds
    5. Let off the pedal completely, wait 3-5 seconds
    6. Turn off ignition, wait at least 10 seconds.
    I don't understand "activate kick down switch"????

    - - - Updated - - -

    Quote Originally Posted by vyper202 View Post
    I don't understand "activate kick down switch"????
    Wait.. just googled it lol

  7. #7
    Join Date
    Oct 2008
    Location
    Mclean, Va
    Posts
    1,335
    My Cars
    2000 Bmw 750il
    The only thing I believe you didn't do was check the ignition coils. When my v12 lost power on one bank. The right side ignition coil died. Swap them then the check the exhaust pressure on each side. If its the coil replace both.

  8. #8
    Join Date
    Nov 2018
    Location
    Virginia
    Posts
    35
    My Cars
    1998 750IL
    Well relays are good, they energize and send voltage out. Looks like I'm switching coils in the morning to try that.

  9. #9
    Join Date
    Nov 2018
    Location
    Virginia
    Posts
    35
    My Cars
    1998 750IL
    Relays are good.... Looks like I'm going to try switching the coils in the morning.... Would love for that to be it....

  10. #10
    Join Date
    Nov 2018
    Location
    Virginia
    Posts
    35
    My Cars
    1998 750IL
    Well swapping coils and crank sensors didn’t do it..., looks like may be a trip to the dealer...

  11. #11
    Join Date
    Feb 2009
    Location
    KC North, MO, USA
    Posts
    11,153
    My Cars
    1996 740iL
    You really need a proper diagnosis. If you live in an urban area, a good German indy shop could scan the car. The KC area has mobile mechanics that will come to your house and run a diagnostic scan as well.

  12. #12
    Join Date
    Nov 2018
    Location
    Virginia
    Posts
    35
    My Cars
    1998 750IL
    Chuck,
    There is only 2 in my area and they have both had their turn at it....

  13. #13
    Join Date
    Oct 2013
    Location
    Waldorf, MD
    Posts
    8
    My Cars
    2001 BMW 750iL
    I am having a similar problem. Jim here, long term lurker, first time posting. My situation started much like the thread of user '1999750il', but that thread never had a resolution. DME 2 seems to be in limp mode with a fixed throttle position sensor reading, and no long or short term fuel trim. All new MAF and all new O2's, smoke tested and all vacuum leaks corrected. Running gutless on one bank, just really sad to drive. It all started with a new Schwaben scanner. After I first used it, it seemed like bank 2 DME just decided to pout and not play. I'm going to try to re-sync the throttle bodies and check the relays as noted above, but frankly the other thread had a line of thought that rebooting the DME's and then synching DME/EWS might do the trick. I am in MD and am picking the brain of a NOVA indy, but haven't heard from him if he's up for the job. Will post if he is. I also considered just calling Passport up in Clinton MD and just telling them to try that specific task and see how it goes. Frankly I'd rather just do it myself, but there is a steep learning curve with DIS and INPA, whatever those actually are (computer programs, black magic, arcane mystical powers only a true initiate may wield, not a noob like me).

  14. #14
    Join Date
    Mar 2011
    Location
    Greenville, NC
    Posts
    506
    My Cars
    2001 7-S62, 2002 X5 S2,
    I had this issue on a 7.98 750iL that I once owned. The issue was a dead/bad DME. Swap the DME's and see if the other side wakes up. If it does, there's your problem. The only solution is to find a matching batch/serial number on eBay and send them off to be cloned. DUDMD was able to do this with mine.
    2001 | DINAN 7 Sport | S62 Swapped 6-Speed
    DINAN Springs & Exhaust | 750 Brakes | M-Pars | Monsoons | NBT Nav/Radio
    Dual Pane Glass | Black & Sand Int.

    2001
    | 750iL | AlpineWeiss III

    @scotthduke on Instagram


Similar Threads

  1. 98 528i running hot! please help
    By wildman378 in forum 1988 - 1996 (E34)
    Replies: 5
    Last Post: 09-24-2004, 10:40 AM
  2. Lightweight flywheel install in Project X ('98 750iL/6)
    By Rob Levinson in forum 1995 - 2001 (E38)
    Replies: 10
    Last Post: 08-14-2004, 11:32 AM
  3. EBC red pad update on '98 750iL/6
    By Rob Levinson in forum 1995 - 2001 (E38)
    Replies: 2
    Last Post: 09-01-2003, 02:40 AM
  4. New dyno results on my '98 750iL/6
    By Rob Levinson in forum 1995 - 2001 (E38)
    Replies: 5
    Last Post: 06-18-2003, 01:30 AM

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
  •