Page 1 of 3 123 LastLast
Results 1 to 25 of 53

Thread: bad idle

  1. #1

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64

    bad idle

    My truck is starting to not idle. If I put it in neutral at a light and hold it at 1500 it will be fine. If I leave it in gear it misfires and then sputters as I take off. It has to Rev up to clean out.
    It reminds me of my old drag car loading up and runs better after snapping the throttle to clean it out.

    I have no idea how a fuel injected engine would do that. The idle sometimes cycle up snd down too.

    It only seems to happen in closed loop.

    Amy ideas?

  2. #2


    Array
    Status
    Offline
    Join Date
    01-16-2014
    Posts
    464
    Location

    Las Vegas, NV
    Vehicle

    1991 Mitsubishi Mighty Max
    Engine

    4G64
    When was your last full tuneup?

  3. #3

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    its all new

  4. #4

    Array
    Status
    Offline
    Join Date
    10-07-2014
    Posts
    16
    Location

    Michigan
    Vehicle

    1988 Mitsubishi Mighty Max
    Engine

    G63B
    sounds like bad spark, my 88 was doing similar and I just changed the plugs (today actually) the old ones were looking pretty old/fouled

  5. #5


    Array
    Status
    Offline
    Join Date
    01-16-2014
    Posts
    464
    Location

    Las Vegas, NV
    Vehicle

    1991 Mitsubishi Mighty Max
    Engine

    4G64
    Did you do all of it or did you just replace only a few things?

  6. #6



    Array
    Status
    Offline
    Join Date
    03-16-2011
    Posts
    3,803
    Location

    Sacramento, CA
    Vehicle

    1979 Dodge D-50
    Engine

    Chevy V6
    Have you looked for vacuum leeks? The hoses are nearly 30 years old so they do come apart. Also check for stretched timing belt. If you have never changed it. Do it now before you get stranded along the road.
    Members come and members go, But the board keeps track of them.
    Find me on FaceBook
    clicking HERE.

    Or look on YouTube Click Here.
    http://mobilemillwright.com

  7. #7

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    Wires. .cap ..rotor..new timing belt...plugs

    I'm changing the fuel filter tonight. .

  8. #8


    Array
    Status
    Offline
    Join Date
    01-16-2014
    Posts
    464
    Location

    Las Vegas, NV
    Vehicle

    1991 Mitsubishi Mighty Max
    Engine

    4G64
    The only other probable issue (other than fuel filter) is the TPS. If it's worn out, or out of adjustment, it will act like that. A fuel filter will definitely do what you are describing if it is clogged though.

  9. #9

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    Ok...I have checked the tps and it is within spec..I was thinking egr too but haven't checked it.

    Now today it drove great...and I have done nothing to it

  10. #10

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    Well I swear the filter must have been original and some of the fuel that came out of the filter looked kinda brown at first.
    The truck got pep now and actually pulls past 4000 now

  11. #11

    Array
    Status
    Offline
    Join Date
    12-10-2014
    Posts
    52
    Location

    Spearfish, South Dakota
    Vehicle

    1991 Dodge Power Ram 50
    Engine

    6G72
    Look at the Idle air control valve (IAC) on the throttle body. this is most likely your problem if not part of it. The coils in the stepper motor go out and give you bad idle and eventual burn up your ECU, been there. Is the IAC brown or black?

    fallow this video on how to test the IAC:
    https://youtu.be/KibYz21IMA0
    It is the same testing procedure for all Mitsubishis up until about 2000.

    This is where you can buy a new quality IAC motor that is improved and reliable on the cheap:
    http://www.ninjaperformance.com/mits...8e12c33664589c

  12. #12

    Array
    Status
    Offline
    Join Date
    12-10-2014
    Posts
    52
    Location

    Spearfish, South Dakota
    Vehicle

    1991 Dodge Power Ram 50
    Engine

    6G72
    Please let me know if this works for you.

  13. #13

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    I will check this out next!!!

  14. #14

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    It started misfiring in gear at stop.lights again today.

  15. #15

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    The idle is cycling up and down...I think your right..The idle control.
    It's the black one.

  16. #16




    Array
    Status
    Offline
    Join Date
    03-20-2011
    Posts
    4,851
    Location

    Pittsburgh, PA
    Vehicle

    1980 Dodge D-50
    Engine

    G54B
    it can also be the ECM - bad caps can cause this.
    Pennyman1
    The best Dodge that Dodge never made
    Living the D-50 lifestyle since 1980

  17. #17

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    http://www.ebay.com/bhp/mitsubishi-l...-control-valve

    Are they all the same?

    I can't find the part number to cross over to another brand.

  18. #18


    Array
    Status
    Offline
    Join Date
    01-16-2014
    Posts
    464
    Location

    Las Vegas, NV
    Vehicle

    1991 Mitsubishi Mighty Max
    Engine

    4G64
    They're not all the same.

    The jumpy/bouncy idle is usually caused by the TPS not responding correctly, or the ECU not knowing when the throttle is closed.

  19. #19

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    I can't get an IAC in canada for this truck.

    If I hop over the border to Autozone would anyone have a part number?

    The O'rielly's website give me a throttle speed valve not the IAC when I go on their site.

    I have found a few numbers but not sure. Any suggestions

  20. #20

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    I now see that the whole thing is a unit md614351....
    It has 2 plugs were all the replacements I've found have only one and the plugs don't match at all.

    I'm at a loss of what you could get at auto zone that could have replaced this....

  21. #21


    Array
    Status
    Offline
    Join Date
    08-31-2011
    Posts
    832
    Location

    Calgary, Alberta, Canada
    Vehicle

    1981 Dodge D-50
    Engine

    Ford V8
    I found this for a 1900 Ram50 http://www.rockauto.com/catalog/more...nid=600&jpid=6 its a 2 plug and you should be able to get it ordered from Canadian tire. I would order it from Rockauto as it will be 1/3rd the price even with exchange and shipping.

  22. #22

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    Holy crap...with exchange that's about $500 can.

  23. #23



    Array
    Status
    Offline
    Join Date
    07-24-2012
    Posts
    2,363
    Location

    Washington State
    Vehicle

    1986 Mitsubishi Mighty Max
    Engine

    G63B
    Wouldn't be better to take the ECM out and check it for burnt caps or bad solder points before you spend all that money and it isn't the problem. It sure could be the problem and they are also easy to pull out, but if it isn't and you spend that cash, you will be kicking yourself even harder when your wallet is empty. Perhaps even try one from another truck if available before pouring out that kind of money.

  24. #24

    Array
    Status
    Offline
    Join Date
    06-27-2015
    Posts
    418
    Location

    Bothwell,Ontario
    Vehicle

    1991 Dodge Ram 50
    Engine

    4G64
    Good idea..
    I have noticed that idle has improved since the fuel filter change and 4 containers of fuel injector cleaner run through the tank.

    The idle seems much less iratic.

    The tps and the motor sensor and servo checked in spec last night with the multimeter so I'm headed to the ecu

  25. #25

    Array
    Status
    Offline
    Join Date
    12-10-2014
    Posts
    52
    Location

    Spearfish, South Dakota
    Vehicle

    1991 Dodge Power Ram 50
    Engine

    6G72
    I am glad you fallowed the video I linked above and checked the coils on the IAC and did not just replace it.

    If you need a ECU rebuild send it to AV Pro, they do work for aerospace and have an excellent reputation along with a life time warranty for $190.00, or take your chances on eBay...

    http://www.avproecm.com/

    http://www.avproecm.com/mitsubishi.htm

Page 1 of 3 123 LastLast

Tags for this Thread

Bookmarks

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
  •