Results 1 to 13 of 13

Thread: MXV wont idle

  1. #1
    apriliaforum Member
    Join Date
    Sep 2014
    Location
    Portugal
    Posts
    249

    MXV wont idle

    Hi,

    Rebuilt my MXV after a catastrofic failure (broken rod). After rebuild it was running fine, did about 1h of slow pace track time and shut the bike off.
    After an oil change, the bike doesn't want to start. It starts if I hold the throttle open but won't idle without throttle.

    I'm suspecting it's the stepper motor that controls the idle.
    Today connected the bike to the computer and only had this error: (Haven't checked this for a long time, could also be a old error)

    CERR_P0505 - Bypass Valve Malfunction - ERROR

    Bypass valve refers to the stepper motor? Should I replace the motor itself (part #
    855771), is it fixable or do I need something else?

    Curiously when shutting down the bike I get some white smoke slowly comming out of the exhausts (both cylinders)
    Replaced both sparkplugs, front was dark, rear was dark and wet.
    Engine has been resealed, stator and flywheel replaced.

    Let me know what you guys think of this
    Thanks

    Note: For the fun it, here goes a photo of the bike.

    Click image for larger version. 

Name:	1.jpg 
Views:	11 
Size:	100.6 KB 
ID:	378828

  2. #2
    apriliaforum expert levisik's Avatar
    Join Date
    Sep 2014
    Location
    Poland
    Posts
    1,569
    is there a different TBs than in SXVs ? In our SXV iddle is cotrolled manually via screw. I don't know how it is made in MXV, but maybe similar ?
    2006 Aprilia SXV 450
    Tuneboy Cable available in Poland

  3. #3
    apriliaforum expert SXVINWA's Avatar
    Join Date
    Feb 2009
    Location
    Tri-Cities, Washington
    Posts
    5,295
    MXV is very different. ECU and idle circuits are nothing like the SXV.

    As I understand it having never seen an MXV, the stepper motor is the bypass valve. When the engine is shut off the ecu uses the voltage present from the stator to drive the stepper motor open to be prepared for a future cold start, which could explain the change in exhaust. When the engine is stopped unexpectedly (stall, dropped clutch, etc) the first few kicks are used to drive the stepper motor open. Maybe check connections in the airbox? It seems the stepper is doing something, but maybe not fully connected?

    Sorry I don’t have better suggestions.

  4. #4
    apriliaforum Member
    Join Date
    Sep 2014
    Location
    Portugal
    Posts
    249
    Quote Originally Posted by levisik View Post
    is there a different TBs than in SXVs ? In our SXV iddle is cotrolled manually via screw. I don't know how it is made in MXV, but maybe similar ?
    Its different. On the MXV the TB flap closes completely and the idle is controller by a stepper motor between the TB.

    As an update, I've removed the stepper motor, it was a little greasy but nothing obvious. Tested the resistance between the A-D and B-C pins and got around 50ohms which is OK.
    Checked the continuity of the connector until the ECU and all 4 pins are OK.

    Could it be broken and still get the right resistance values? Any way to test the actual stepper motor?

  5. #5
    apriliaforum expert SXVINWA's Avatar
    Join Date
    Feb 2009
    Location
    Tri-Cities, Washington
    Posts
    5,295
    You should be able to use jumpers to simulate inputs to the stepper motor and drive it open and closed. Plenty of info about stepper motors on the internet to teach you how to pulse the coils, but remember that every pulse only moves the rotor a tiny bit. It will most likely take many pulses to see a noticeable change in opening.

    As I said earlier, what you observed in exhaust tends to indicate that the stepper motor is changing positions. You may have just viewed an old error code as you suspected and your true issue is elsewhere.

  6. #6
    apriliaforum Member
    Join Date
    Sep 2014
    Location
    Portugal
    Posts
    249
    Thanks for your inputs SXVINWA, do you have any sugestions where to look next?

    This would take a lot of work, but I'm about to take the hole airbox from the other mxv and place it into this engine. This would determine if its engine fault or electronic.
    Then replace part by part. The problem here is that the airbox is designed in a way that its very hard to replace something without pulling out the engine

  7. #7
    apriliaforum expert SXVINWA's Avatar
    Join Date
    Feb 2009
    Location
    Tri-Cities, Washington
    Posts
    5,295
    I’m sorry, but I have almost no experience with the mxv.

    Maybe try just exchanging the stepper assembly first.

  8. #8
    apriliaforum Member
    Join Date
    Sep 2014
    Location
    Portugal
    Posts
    249
    Will try that.

    Found this topic, appears to be a similar issue:

    https://www.apriliaforum.com/forums/...V-Idle-problem

  9. #9
    apriliaforum expert SXVINWA's Avatar
    Join Date
    Feb 2009
    Location
    Tri-Cities, Washington
    Posts
    5,295
    Do you have the ability to observe engine coolant and air temp values with the MXV software?

  10. #10
    apriliaforum Member
    Join Date
    Sep 2014
    Location
    Portugal
    Posts
    249
    From what I remember it does not, however I'm not sure.
    Maybe connecting it to XVTuner might give that information.

    Read what you told about the temp sensor, that would make the stepper work fine even with a broken temp sensor right?

  11. #11
    apriliaforum expert SXVINWA's Avatar
    Join Date
    Feb 2009
    Location
    Tri-Cities, Washington
    Posts
    5,295
    A bad temp sensor would make an ECU send a stepper motor to the incorrect position, which would throw off engine performance.

  12. #12
    apriliaforum expert daws's Avatar
    Join Date
    May 2009
    Location
    Sunshine Coast, Aus
    Posts
    1,067
    Quote Originally Posted by SXVINWA View Post
    Do you have the ability to observe engine coolant and air temp values with the MXV software?
    Yes, the MXV software (ServiceOem564.exe) console shows Air temp and engine temp.

    Did you remove the throttle body link when you rebuilt the engine or synced the throttle bodies? The MXV Throttle body link has a slot and a hole for the rear throttle body. The rear throttle body should be driven by the slotted part of the linkage, the rear starts to open once the front reaches 10%.

    Do you have a copy of the MXV Service manual? I can email you a copy.


    #314 - Aprilia SMXV450
    Snap Fitness Caloundra - www.snapfitness.com.au/caloundra
    Übermoto Custom Graphics - www.uber-moto.com
    M2R helmets - www.made2race.com.au/
    Duke Racing Represent!


  13. #13
    apriliaforum Member
    Join Date
    Sep 2014
    Location
    Portugal
    Posts
    249
    Quote Originally Posted by daws View Post
    Yes, the MXV software (ServiceOem564.exe) console shows Air temp and engine temp.

    Did you remove the throttle body link when you rebuilt the engine or synced the throttle bodies? The MXV Throttle body link has a slot and a hole for the rear throttle body. The rear throttle body should be driven by the slotted part of the linkage, the rear starts to open once the front reaches 10%.

    Do you have a copy of the MXV Service manual? I can email you a copy.
    Thanks daws.
    I haven't messed with the TB on the rebuild.
    The fact that the bike ran ok the whole afternoon and only later had trouble starting up makes me think it might not be directly related to the rebuild.

    Regarding the TB linkage, I have it infact on the sync position rather than async, however I also have a suitable sync map that ran great for the last two years (also runs on my other mxv). I use 40mm TB and not the 38mm.

    Will check again the MXV software for the temps.

Similar Threads

  1. bike wont idle
    By i_am_tim in forum RS125 Euro-archive
    Replies: 9
    Last Post: 10-16-2007, 12:37 PM
  2. bike wont idle
    By aprilia_rick in forum RS125 Euro-archive
    Replies: 16
    Last Post: 03-29-2007, 04:09 PM
  3. needthe help wont idle
    By rsvApril in forum RSV1000 Mille, Mille R, and Mille SP (1998-2003)
    Replies: 9
    Last Post: 03-21-2007, 10:19 AM
  4. Replies: 31
    Last Post: 04-09-2005, 07:26 AM
  5. Wont Idle
    By Henderson in forum RS50 Technical
    Replies: 1
    Last Post: 05-11-2003, 04:57 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
  •