406 Hdi 2800rpm rev limit ???
  • Register
  • Help
Results 1 to 11 of 11
  1. #1
    Member
    Join Date
    Jun 2001
    Location
    Adelaide, SA ,Australia
    Posts
    42

    Default 406 Hdi 2800rpm rev limit ???

    Most peculiar behaviour from an otherwise reliable car, 'till now. Two things happened (I think) at once : a delay in shutdown once the key was turned to "off" developed, and on the same day, a complete refusal to pass 2800 rpm, regardless of load, ie it pulls to there in each gear, but no further even in neutral. It's rather as if the cruise control is working through the rev counter rather than the speedo.
    At 3pm today when first driven, it was normal, then having been parked for a while, the fault returned. it's certainly improving the economy!! Another fault which has occasionally occurred over the last 3 months, is that the tacho drops to zero while driving, accompanied by some loss of power. Does anyone have any ideas? Someone suggested a blocked filter, but surely that would limit power, not revs . . Jon Hardy

    Advertisement
    Currently own '69 404, '72 504 (V6), '72 504 cpe 4cyl (unrest), '74? 504 ti x2, '76 504 auto, '76 504 ti on gas, '80 604SL '81 505(ti) ba10/5 '83 505 (ti) ba7/5 fam,
    '84 505 Sti ba7/5, '86 505 Sli ba7/4 fam (project), 405GRI auto. Too many....

  2. #2
    1000+ Posts Capago's Avatar
    Join Date
    Oct 2010
    Location
    Hornsby, NSW
    Posts
    1,012

    Default

    whatever it is, it sounds expensive...

    if your tacho is dropping off (along with other systems perhaps, radio, lights?) check the battery terminals and any nuts holding the lot together, probably a 13mm nut. (if fitted, not all have it). something quick and easy you can do at home. check for any corrosion or signs that it may have/is loose and arcing out and burning the terminal.

    the other one I dont think can be explained without having a search of fault codes logged. dont bother chasing something like that the old fashioned way, you'll be wasting time and money.
    The wrong oil is better than no oil at all.

  3. #3
    con
    con is offline
    Fellow Frogger!
    Join Date
    Jul 2001
    Location
    sydney, nsw, australia
    Posts
    521

    Default

    Quote Originally Posted by jonhardy View Post
    ... Another fault which has occasionally occurred over the last 3 months, is that the tacho drops to zero while driving, accompanied by some loss of power. Does anyone have any ideas? Someone suggested a blocked filter, but surely that would limit power, not revs . . Jon Hardy

    This could be the gearbox speed sensor or the speed control unit (Bitron - part no: 1929.SJ).

    Should be described in the Aussiefrogs archives, somewhere.



    con....

  4. #4
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,432

    Default

    Quote Originally Posted by jonhardy View Post
    At 3pm today when first driven, it was normal, then having been parked for a while, the fault returned. it's certainly improving the economy!!
    Jon, you are clearly a man who can see the positive in every situation.

    Jo

  5. #5
    Fellow Frogger! gromzx's Avatar
    Join Date
    May 2011
    Location
    melborne
    Posts
    364

    Default

    have you had any other oddities with the car like:
    Hard starting or starting and stalling straight away if you try to start it straight away without leaving the key on the on position for a few seconds?
    Strange acceleration when cold? (surging or hesitation)
    Engine light coming on?
    Stalling?
    Does everything else work as normal? (gauges, lights...)

    Also
    have you changed the fuel and air filters?
    is it an auto or manual?

    Sorry about all the questions but when it comes to these engines, there are so many things that could cause problems like this.
    (any one faulty sensor could send the computer into limp mode)
    If you can have the computer checked for fault codes, this would be vary helpful as it should tell you if there is a faulty sensor, or at least point you in the right direction.

  6. #6
    Fellow Frogger! Balki's Avatar
    Join Date
    Nov 2010
    Location
    Sheffield/Tasmania
    Posts
    631

    Default

    I think you will find the not revving past 2800rpm is (if its manual) the clutch switch under the dash is faulty or the pedal is missing the switch altogether

  7. #7
    Member
    Join Date
    Jun 2001
    Location
    Adelaide, SA ,Australia
    Posts
    42

    Default

    Thanks for all these thoughts, but very little has ever varied, other than an occasional loss of performance, as if the boost is only partly coming on. Car is a manual D9 with the earlier of the two gearboxes and the inlet tract has the pneumatic butterfly thingy "above the clutch" for want of a better description of it's location. Today in fact it went better than ever, passing 4K willingly. I changed the engine about 6 months ago (I bought it with a known blown head gasket), and did filters then and one recent oil change since. I will get the fault codes checked out and write up what I find. Jon
    Currently own '69 404, '72 504 (V6), '72 504 cpe 4cyl (unrest), '74? 504 ti x2, '76 504 auto, '76 504 ti on gas, '80 604SL '81 505(ti) ba10/5 '83 505 (ti) ba7/5 fam,
    '84 505 Sti ba7/5, '86 505 Sli ba7/4 fam (project), 405GRI auto. Too many....

  8. #8
    Member
    Join Date
    Jun 2001
    Location
    Adelaide, SA ,Australia
    Posts
    42

    Default

    Thanks for this suggestion. I will look tomorrow. The spare parts car will come in useful very soon I think. Jon
    Currently own '69 404, '72 504 (V6), '72 504 cpe 4cyl (unrest), '74? 504 ti x2, '76 504 auto, '76 504 ti on gas, '80 604SL '81 505(ti) ba10/5 '83 505 (ti) ba7/5 fam,
    '84 505 Sti ba7/5, '86 505 Sli ba7/4 fam (project), 405GRI auto. Too many....

  9. #9
    Fellow Frogger! gromzx's Avatar
    Join Date
    May 2011
    Location
    melborne
    Posts
    364

    Default

    the butterfly valve above the gearbox is for the EGR system.
    It works by choking the intake so it will suck in exhaust gasses from the EGR port (which is located after the choke and is always open).
    It operates on vacuum and sits in the open position when not energized, so it can be disconnected (and the vacuum pipe plugged) and it won't affect engine performance.

  10. #10
    Member
    Join Date
    Jun 2001
    Location
    Adelaide, SA ,Australia
    Posts
    42

    Default

    More useful knowledge. Thanks. And down to 2700rpm yetserday, and stopped twice, must be letting me down gradually.
    The spare later production car doesn't have that valve, and consequently has only 2 rather than 3 vacuum gadgets on the firewall. The turbo appears to be a different type as well.
    Last edited by jonhardy; 15th December 2012 at 08:42 AM. Reason: error in 1st line
    Currently own '69 404, '72 504 (V6), '72 504 cpe 4cyl (unrest), '74? 504 ti x2, '76 504 auto, '76 504 ti on gas, '80 604SL '81 505(ti) ba10/5 '83 505 (ti) ba7/5 fam,
    '84 505 Sti ba7/5, '86 505 Sli ba7/4 fam (project), 405GRI auto. Too many....

  11. #11
    Fellow Frogger!
    Join Date
    Jun 2011
    Location
    Tasmania, Australia
    Posts
    218

    Default

    406 HDI ISSUES

    As Capago says, check and clean battery terminals first.
    When i purchased my last 306 HDi it had the tacho needle dropping down to zero on startup with the speedo occasionally doing the same.
    The positive battery clamp on the late 306 (406 prob. the same) is a lift up lever type.
    Just lift up and twist backwards and forwards a few times with WD spray applied while pressing down on the lever (that way you wont have have to reset stereos and clocks.
    Of course if it will need a proper clean , wire brushing if in a bad way

    Alain

Thread Information

Users Browsing this Thread

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

Posting Permissions

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