OUR VIDEOS GALLERY MEMBER SPONSORSHIP VENDOR SPONSORSHIP

User Tag List

Page 2 of 4 FirstFirst 1234 LastLast
Results 11 to 20 of 33

Thread: limp mode??

  1. #11
    Patrol God threedogs's Avatar
    Join Date
    Jun 2012
    Location
    Melb
    Posts
    31,634
    Thanks
    10,350
    Thanked 9,963 Times in 7,394 Posts
    Mentioned
    113 Post(s)
    Tagged
    2 Thread(s)
    not doubting just needed some clarification, I run 19psi max boost and mine never goes into limp mode.
    The longer we have these motors seems the more we find out about them.
    Whats a voltage modifier look like out of interest and is it a big mod or fairly simply.
    I have my ECU-Talk in view when I drive I'll see what readings the MAF says
    04 ST 3lt auto, not enough Mods to keep me happy, but getting there

  2. #12
    Advanced Mud Gecko's Avatar
    Join Date
    Aug 2013
    Location
    Darwin NT
    Posts
    66
    Thanks
    9
    Thanked 42 Times in 25 Posts
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Mate if you don't get limp mode that's great! I wouldn't worry about it then. But for those that do you'll need this-

    http://www.jaycar.com.au/productView.asp?ID=KC5490

    and this-

    http://www.jaycar.com.au/productView.asp?ID=KC5386

    and a degree in electronics to put it all together lol

    or check out this thread- http://www.patrol4x4.com/forum/zd30-...difier-102192/

  3. #13
    Expert Rickie3's Avatar
    Join Date
    Jan 2014
    Posts
    226
    Thanks
    206
    Thanked 54 Times in 37 Posts
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I just went out and removed the blanking plate and put back in the original gasket, and test drove it has stopped the limp mode issue and appears to be running spot on

  4. #14
    Patrol God threedogs's Avatar
    Join Date
    Jun 2012
    Location
    Melb
    Posts
    31,634
    Thanks
    10,350
    Thanked 9,963 Times in 7,394 Posts
    Mentioned
    113 Post(s)
    Tagged
    2 Thread(s)
    Quote Originally Posted by Mud Gecko View Post
    I have a Di, according to the Nissan manual, MAF voltage should be 1.6v-2.0v. With a blocked EGR and no modifier, MAF voltage at idle is 2.2v-2.3v. Without my modifier and running 18psi of boost I will get limp mode at 2500rpm and just under 3000rpm @ WOT in 3rd and 4th. Limp mode is a combination of high boost and high MAF voltage. Usually if you go over 3.98v under 3000rpm you'll get limp.

    With my modifier, I have tuned my MAFv at idle to 1.7v-1.8v. I no longer have that "fuely" smell at idle and I can tune out limp mode by raising or lowering the MAF voltage around those limp points.


    If you don't believe me there is plenty of info on the "other" site, lots of guys doing it now.
    My MAF reads up to 3.9 and a bit driving along normally, with no limp
    04 ST 3lt auto, not enough Mods to keep me happy, but getting there

  5. #15
    Patrol Freak BillsGU's Avatar
    Join Date
    Jul 2010
    Location
    Thurgoona
    Posts
    1,224
    Thanks
    40
    Thanked 601 Times in 389 Posts
    Mentioned
    7 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Mud Gecko View Post
    Mate if you don't get limp mode that's great! I wouldn't worry about it then. But for those that do you'll need this-

    http://www.jaycar.com.au/productView.asp?ID=KC5490

    and this-

    http://www.jaycar.com.au/productView.asp?ID=KC5386

    and a degree in electronics to put it all together lol

    or check out this thread- http://www.patrol4x4.com/forum/zd30-...difier-102192/
    Sounds good. Never knew it existed.

  6. #16
    I am he, fear me the evil twin's Avatar
    Join Date
    Jun 2010
    Location
    W.A. (wandering aust)
    Posts
    6,208
    Thanks
    904
    Thanked 6,642 Times in 3,288 Posts
    Mentioned
    44 Post(s)
    Tagged
    1 Thread(s)
    Well, I bow to popular opinion but something doesn't gel to me.
    I think you are effectively detuning the engine by reducing fuel

    If a MAF is serviceable and its temperature and airflow output voltages are "in spec" then they are proportional to the airflow.

    If you "reduce" the voltage then the ECU is being told "you are getting less air".

    Anyway, no biggee. I'm guess I'm lucky mine runs fine with out the need for a modifier
    Dolphins are so smart that within a few weeks of captivity, they can train people to stand on the very edge of the pool and throw them fish.

  7. #17
    Expert
    Join Date
    Jun 2013
    Location
    Central West NSW
    Posts
    100
    Thanks
    10
    Thanked 24 Times in 17 Posts
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by the evil twin View Post
    Well, I bow to popular opinion but something doesn't gel to me.
    I think you are effectively detuning the engine by reducing fuel

    If a MAF is serviceable and its temperature and airflow output voltages are "in spec" then they are proportional to the airflow.

    If you "reduce" the voltage then the ECU is being told "you are getting less air".

    Anyway, no biggee. I'm guess I'm lucky mine runs fine with out the need for a modifier
    And I think that is where the problem is, when we block EGR more air is dragged past the MAF increasing the the voltage hence increasing the fuel. Restoring the correct voltage ensures the correct amount of fuel and not an increased amount of fuel.
    It would also make wonder though if the ECU has two fuel maps, EGR open and EGR closed. In which case by modifying the voltage it upsets the fuel mapping at times when the EGR is supposed to be closed, eg off idle and not at cruise.

    Just my thoughts?

    Lemo.
    http://www.nissanpatrol.com.au/forums/image.php?type=sigpic&userid=16293&dateline=137569  2513
    2006 GU IV ST 3.0L TD Di
    Autron Boost and EGT, Dual Bat, Dawes & Needle Valves, ARB Alloy rack, more to come.

  8. #18
    I am he, fear me the evil twin's Avatar
    Join Date
    Jun 2010
    Location
    W.A. (wandering aust)
    Posts
    6,208
    Thanks
    904
    Thanked 6,642 Times in 3,288 Posts
    Mentioned
    44 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by Lemo79 View Post
    And I think that is where the problem is, when we block EGR more air is dragged past the MAF increasing the the voltage hence increasing the fuel. Restoring the correct voltage ensures the correct amount of fuel and not an increased amount of fuel.
    It would also make wonder though if the ECU has two fuel maps, EGR open and EGR closed. In which case by modifying the voltage it upsets the fuel mapping at times when the EGR is supposed to be closed, eg off idle and not at cruise.

    Just my thoughts?

    Lemo.
    That is where it doesn't quite work with me as well.
    I think it is a hide the symptom versus cure the problem but Pffft, both will stop a limp mode.
    I guess it is only needed for MAF's that have a 'higher' output for a given airflow.

    I want more air so my ECU and Chip can feed more fuel so I get more herbs.
    The MAF sensor is saying you are now getting more air so have more fuel.
    I modify the signal to say you are getting less air.
    The ECU then takes fuel so I get less grunt.

    ... and to make it more complicated the EGR valve control is different between the Di and CRD
    AFAIK CRD's aren't an "open/close" valve, they are a stepper motor.

    Anyway, the OP has a Di so I'll bow out and stop confusing the issue with my CRD gibberish.
    Dolphins are so smart that within a few weeks of captivity, they can train people to stand on the very edge of the pool and throw them fish.

  9. #19
    Patrol Freak BillsGU's Avatar
    Join Date
    Jul 2010
    Location
    Thurgoona
    Posts
    1,224
    Thanks
    40
    Thanked 601 Times in 389 Posts
    Mentioned
    7 Post(s)
    Tagged
    0 Thread(s)
    ET - Just kicking around some thoughts. With the ERG unblocked the engine would be getting air from two sources (the normal air intake and the air supplied via the EGR). The ECU would supply fuel proportional to this amount of air. The only metered portion is via the normal air intake, where the MAF senses the amount of fresh air supplied. I would imagine that the ECU would compensate for the air that is also supplied via the EGR.

    When the EGR is blocked the ECU would not know that this amount of air is now shut off and the engine would be getting less air than it should have for the amount of fuel supplied. This device would allow the adjustment of the correct air / fuel ratio by making the ECU think there is less air entering the engine than there actually is.

    Does this makes sense ...................................... ?

  10. #20
    Advanced Mud Gecko's Avatar
    Join Date
    Aug 2013
    Location
    Darwin NT
    Posts
    66
    Thanks
    9
    Thanked 42 Times in 25 Posts
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by the evil twin View Post
    That is where it doesn't quite work with me as well.
    I think it is a hide the symptom versus cure the problem but Pffft, both will stop a limp mode.
    I guess it is only needed for MAF's that have a 'higher' output for a given airflow.

    I want more air so my ECU and Chip can feed more fuel so I get more herbs.
    The MAF sensor is saying you are now getting more air so have more fuel.
    I modify the signal to say you are getting less air.
    The ECU then takes fuel so I get less grunt.
    You are correct. I don't have a chip. I only reduce MAF voltage at idle, above idle I actually increase the voltage thus increasing fuel (sort of a poor mans chip ). I only need to reduce the voltage at particular points in the upper rev range when I get limp, it can be a surprisingly small amount that makes all the difference.

    If you don't have issues with limp mode then I wouldn't worry about it. It seems these cars each have their own idiosyncrasies...

Page 2 of 4 FirstFirst 1234 LastLast

Posting Permissions

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