Page 1 of 2 1 2 LastLast
Results 1 to 10 of 13
  1. #1

    Join Date
    Jul 2009
    Location
    WA USA
    Posts
    148
    +1
    1

    MSX 150 Sometimes doesn't power up, randomly

    I've got an msx150 that will randomly not fire up.

    The machine will work one day but randomly not work out of the blue.

    What I mean is that the fuel pumps, computer won't turn on allowing no spark to the system. Is this early failure of the SIFB?

    Battery is brand new so I'm getting proper voltage.

    Any ideas?
    Last edited by K447; 09-08-2014 at 03:51 PM. Reason: Is MSX 150, not MSX 140


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,587
    +1
    1,272
    This is MSX 140 or MSX 150? Very different engines.

    With lanyard in place, what happens when you press Start?
    Does the digital display 'wake up' from sleep when the engine starts cranking?

  3. #3

    Join Date
    Jul 2009
    Location
    WA USA
    Posts
    148
    +1
    1
    Sorry It's an MSX 150. I'll put the key in. Gauges and everything turn on engine will crank but no start. Then I can try an hour or two later, I'll put the key in and the systems will turn on and make noise for initial startup as its supposed to do (Fuel pump, computers etc). It just gets no spark like the computers aren't turning on.

  4. #4
    ripcuda's Avatar
    Join Date
    May 2010
    Location
    Newman Lake, WA
    Posts
    2,389
    +1
    166
    I've seen similar symptoms with a bad SIFB.

    I'd pop the fuel injectors off (still on the rail) and crank it to see if they're spraying. Then pull the plugs and put the coil packs on them and ground the plug and see if it's sparking. Betting it's lack of spark causing your issue. Which would point to weak battery (probably not your issue)... with SIFB being the next thing to check.

    Thankfully they are more affordable now.

    Cheers!

  5. #5

    Join Date
    Jul 2009
    Location
    WA USA
    Posts
    148
    +1
    1
    ?Anyone have a link on where to buy these aftermarket SIFB's?

  6. #6

  7. #7
    GGG's Avatar
    Join Date
    Sep 2009
    Location
    Jersey Shore
    Posts
    2,830
    +1
    258
    if you unplug the SIFB and jump the purple to the blue/white, it will over ride the box and it will start. Im just not sure if you will get a check engine light from doing that. also you will no longer have a reverse limiter

  8. #8

    Join Date
    Jul 2009
    Location
    WA USA
    Posts
    148
    +1
    1
    So should I just remove it all together and jump those wires? or leave it plugged in with the wires jumped? I'm going to try this first.

  9. #9
    ripcuda's Avatar
    Join Date
    May 2010
    Location
    Newman Lake, WA
    Posts
    2,389
    +1
    166
    I would be curious if this "bypass" works. The SIFB powers down the ignition system. So do you have to disconnect this bypass to power down? Sounds like you would need to. If you don't power down, you'll drain the battery.

    Also the reverse rev-limiting done by the ECU that gets the reverse switch input from the SIFB... is very useful for starting out of the water... where the Weber is known to rev sky high (out of the water... no pump load).

    Cheers!

  10. #10
    GGG's Avatar
    Join Date
    Sep 2009
    Location
    Jersey Shore
    Posts
    2,830
    +1
    258
    Leave the sifb disconnected and removing the lanyard will power down the system
    Putting 12v to the green with yellow tracer will enable the reverse limit. All the SIFB does for the reverse circuit is swap the signal because the reverse switch supplies 12v when in forward and disconnects when in reverse. This can be done with a simple transistor circuit or a relay.

    I would test the over ride on a working ski if I had one here. Unfortunately the one here is not running properly to begin with and I do not have the diagnostics to figure it out

Page 1 of 2 1 2 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Replies: 9
    Last Post: 06-24-2015, 03:55 PM
  2. MSX 150 revs out of control up to 7900 rpms...wont stop
    By Rhett in forum Polaris Open Discussion
    Replies: 8
    Last Post: 09-27-2014, 12:46 PM
  3. MSX 110/150 - insert lanyard... system power up?
    By ripcuda in forum MSX/Matrix
    Replies: 7
    Last Post: 04-22-2013, 05:32 PM
  4. MSX 150 Sudden Problem - No Power
    By rcsscraig in forum MSX/Matrix
    Replies: 17
    Last Post: 07-01-2011, 09:25 PM
  5. MSX 150 won't start back up
    By Todd in forum Polaris Open Discussion
    Replies: 20
    Last Post: 04-28-2007, 07:26 PM

Posting Permissions

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