Results 1 to 12 of 12

Thread: M50 E85 ethanol turbobuild issue

  1. #1
    Join Date
    Apr 2006
    Location
    Frankfurt / Germany
    Posts
    169
    My Cars
    '91 E30 330i turbo

    M50 E85 ethanol turbobuild issue

    Hi guys,

    I'm really struggling with my M50 ethanol build.
    Main issue is that the engine wont start the first time even at higher temperatures.

    I tried a lot of settings for weeks in order to achieve an acceptable cold start performance. Nevertheless the best I could achieve is a setting, where I need to crank for more than 10 seconds before engine starts running. Firstly, I thought is was related to low air temperatures (below 15°C) however the issue exists also at higher temperatures (more than 25°C) as we had the last weeks.

    If the engine decided to idle finally, I can switch off the engine an re-start without any issues. (Engine starts normal)

    I added my cranking table and my fuel table… maybe someone has an idea what could be wrong.
    cranking.JPGfuel-table.JPG

    I'm running a MS2 on a 2,8l M50 engine with 120lbs injectors.

    Thanks
    Torsten

  2. #2
    Join Date
    Jun 2011
    Location
    Vancouver, BC Ca
    Posts
    3,255
    My Cars
    1993 325is
    Try simply turning on the key to the run position (do not start the engine) and leaving it there for a few seconds, then shutting it off and doing this again to see if this improves the starting performance. Once you've cycled it once or twice, then attempt to start it. It is possible that your fuel system is not maintaining any residual pressure and this on/off key actuation before attempting to start the engine will raise pressure to a normal level (if this is your problem).

  3. #3
    Join Date
    Apr 2006
    Location
    Minnesota eh?
    Posts
    6,155
    My Cars
    86 325es
    Most likely need to mess with the cranking table some more. Make sure the setting for cranking rpm is higher than your actual rpm when cranking. The symptom you describe sounds like it does not have enough fuel but your settings look really really high. Do you have a fuel pressure gauge?

    Also the air temp is not a problem. E85 will start just fine at -30 C with the correct settings. I’ve tried.


    86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
    best time 9.06 @ 151.8 mph, best 60 foot 1.30

  4. #4
    Join Date
    Apr 2006
    Location
    Frankfurt / Germany
    Posts
    169
    My Cars
    '91 E30 330i turbo
    Thanks guys for your reply.

    Fuel pressure gauge is installed and shows 43psi directly after go into run position. So I assume no issues with the fuel system.

    @someguy2800: I understood the cranking table as an percentage increase (over 100%) or decrease (below 100%) of the actual values in the fuel-table while cranking. Is that correct?

  5. #5
    Join Date
    Aug 2010
    Location
    NY/FL
    Posts
    2,725
    My Cars
    '08 G35S, '98 M3/4/5
    The last time I had this issue with a car, it was the actual injectors bleeding off fuel pressure when the car sat. I looked at EVERYthing else beforehand because they were brand new and I had them cleaned and flow tested. Went through 14 crank table revisions, new FPR, LPFP, etc, back to more maps. Replaced the injectors on a whim and boom, cold start perfect again.
    Infiniti G35S Turbo BMW M3/4/5 Ninja ZX6R 636
    Penn State University '08...better than your school since 1855
    Sigma Lambda Beta International Fraternity Incorporated

    UTI Class of '10, BMW "STEPchild"
    Acurazine.com Mod Squad

  6. #6
    Join Date
    Aug 2007
    Location
    Vancouver, B.C., Canada
    Posts
    8,162
    My Cars
    '97 M3
    Is that 43 psi with it running and at idle with the vacuum line connected to the FPR?

    I know you are on a stand-alone but the stock fuel system pressure should be 52 psi when you turn the key to the on position without starting the engine. The off and back on trick that Jaker suggested should get you to 52 psi if the system is functioning and adjusted correctly.

  7. #7
    Join Date
    Apr 2006
    Location
    Frankfurt / Germany
    Posts
    169
    My Cars
    '91 E30 330i turbo
    43psi at idle - sorry.

    I dont know… I tried the whole afternoon "on-off-on-off-idle-off-on...…" I even missed the first half of the Germany soccer game (okay, it wasnt worth seeing and we lost - but thius is another story).
    Finally I can say, that I didn't find a better setup - I just recognized that I have heavy hot start issues if water temp is above 95°C... Engine starts barley, only with 1 or 2 Cylinders and dies after a few seconds… after starting maybe ten times, engine starts again on 5 Cylinders and after some revs above 3000rpm you can feel that Cylinders running again.
    Anyway… not a good day for tuning… maybe it is better to remove all the Ethanol again and start tuning on 100% gas. However I dont know whether I can achieve a smooth idle with such big high-resistance injectors… I assume they are already borderline even with 30% more duty cycle on E85. :-/



  8. #8
    Join Date
    Apr 2006
    Location
    Minnesota eh?
    Posts
    6,155
    My Cars
    86 325es
    Quote Originally Posted by torsten View Post

    @someguy2800: I understood the cranking table as an percentage increase (over 100%) or decrease (below 100%) of the actual values in the fuel-table while cranking. Is that correct?

    No not exactly, its a percentage of the Req fuel number. Here is my cranking table.



    86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
    best time 9.06 @ 151.8 mph, best 60 foot 1.30

  9. #9
    Join Date
    Oct 2006
    Location
    Toronto, Canada
    Posts
    3,375
    My Cars
    E36 Turbo
    post your config/and logs.... nothing that you have shown or said here helps anyone enough to be able to start to help.

    for all we know your tune can be completely off the charts. Remember corrections are only to be adjust once your base tune is correct. ie. injector setup, req_fuel is correctly set, and your VE table tuned.

    If you're having issues starting your car even when your engine is warm the issue is most likely a base calibration issue and this is why you won't get a good start no matter what the temp (hot or cold) and why changing your correction tables doesn't help at all. There could be a chance also that there is a hardware issue (faulty injectors, etc). But there is less of a chance of that from right now.

  10. #10
    Join Date
    Apr 2006
    Location
    Frankfurt / Germany
    Posts
    169
    My Cars
    '91 E30 330i turbo
    @someguy2800: Thanks for sharing your cranking table. I really appreciate your help!
    I also jumped back with most of the parameters to a tune I made a couple of years before for my M52 turbo pump gas project. With that and your shared crank table I will make some trials within the next hours.

    @all: I attached my current tune - your recommendations are welcome :-)
    https://webmail.freenet.de/Cloud/?sh...d6574a1fe47e91

    ----EDIT---

    ...back from testing - well I can say… it worked :-)
    I still have a minor issue that directly after engine starts firing it would need some automatic increase of the air flow rate for jsut a few seconds in order to avoid engine starts heavy alternating between 600 and 1400prm. Anyway I can compensate this by open the throttle very slightly for the first 5 seconds after cranking - then engine idles quite smooth.
    So I would say: target for the day: achieved! :-)

    Again thanks your for great support and as I already mentioned above any recommendations regarding my setup are welcome!


    Thx
    Torsten
    Last edited by torsten; 06-19-2018 at 12:17 PM.

  11. #11
    Join Date
    Apr 2006
    Location
    Minnesota eh?
    Posts
    6,155
    My Cars
    86 325es
    Quote Originally Posted by torsten View Post
    @someguy2800: Thanks for sharing your cranking table. I really appreciate your help!
    I also jumped back with most of the parameters to a tune I made a couple of years before for my M52 turbo pump gas project. With that and your shared crank table I will make some trials within the next hours.

    @all: I attached my current tune - your recommendations are welcome :-)
    https://webmail.freenet.de/Cloud/?sh...d6574a1fe47e91

    ----EDIT---

    ...back from testing - well I can say… it worked :-)
    I still have a minor issue that directly after engine starts firing it would need some automatic increase of the air flow rate for jsut a few seconds in order to avoid engine starts heavy alternating between 600 and 1400prm. Anyway I can compensate this by open the throttle very slightly for the first 5 seconds after cranking - then engine idles quite smooth.
    So I would say: target for the day: achieved! :-)

    Again thanks your for great support and as I already mentioned above any recommendations regarding my setup are welcome!


    Thx
    Torsten
    You can do that automatically in the idle settings. You can set idle valve position while cranking and then taper that off over a set amount of time.


    86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
    best time 9.06 @ 151.8 mph, best 60 foot 1.30

  12. #12
    Join Date
    Apr 2006
    Location
    Frankfurt / Germany
    Posts
    169
    My Cars
    '91 E30 330i turbo
    Thanks for the hint. Didn't notice this parameter since it was quite well hidden. Increased to 15 sec... now engine goes from cranking into stable idle autonomous.

    Again thank you for your support.

Similar Threads

  1. The M&W is in, TPS issue, and E85 Ethanol Anyone?
    By jonesmechanical in forum Forced Induction
    Replies: 25
    Last Post: 02-25-2010, 03:12 PM
  2. '91 M50 no-start ongoing issue
    By nairmac in forum 1988 - 1996 (E34)
    Replies: 6
    Last Post: 03-12-2009, 05:43 PM
  3. Recent M50/trackpipe/exhaust install issues
    By chisau in forum 1992 - 1999 M3 (E36)
    Replies: 1
    Last Post: 08-23-2007, 01:05 PM
  4. M50 Swapped 318i performance issues
    By slowbird in forum 1991 - 1999 (E36)
    Replies: 9
    Last Post: 06-07-2007, 07:03 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
  •