1. Join the Community!

    DSMtuners is a massive archive of DSM information - but more importantly, it's a COMMUNITY! Join in and participate with other DSMers, and invite all of your DSM friends to make this place their home. Chat with others, create a build thread, post questions and answers. Get involved! Logging in will also remove many of the advertisements, along with this notice. ;)

420A Hesitation/rough idle

Posted by 609DSM, Jan 14, 2020

Please Support ExtremePSI
Please Support Southbay Fuel Injectors
  1. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    My idle is extremely rough when car is at temp. It goes from 950rpm and will drop down to 600 and as low as 500, does this when I come to a full stop at a light. Then it has trouble getting going, I have to really get on the gas to get the rpm to 1.5k to 2k for it to leave a stopped position.

    I cant even go full throttle or what happens is it picks up speed then the torque just dropped and it revs a lot slower and gets a little quieter and all power it had comes to a halt, then randomly it kicks back in and has full power.

    So I cleaned my intake and throttle body, replaced the MAP sensor and the throttle positioning sensor along with my broken coolant temp sensor. I've also checked for vacuum leaks as well and havent been able to find any from my inspections.

    Could this be a fuel issue?
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  2. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    Sounds like the IAC
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.
  3. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    I have a new one but the tip is much shorter than the one that I already have in it. I was thinking of just switching it out and seeing just to try it but havent yet
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  4. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    The tips just unscrew. Unscrew the tip from the old one and put it in the new one. Just be sure you measure the length before doing so or you could take that thing out 15 times to adjust it right. I have spent the last couple of days doing so myself...
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.
  5. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    Okay I'll have to check this out. I tried fiddling around with it but the only movable part I found was the sleeve of the tip
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
    BLACK'98DSM likes this.
  6. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    It is on there pretty tight. I covered it with a towel to keep it from scratching and twisted it off with some pliers. Once you break it loose it should unscrew easily. Just be careful not to damage the tip, hence the towel.
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.
  7. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    Okay. Did what you said. Measured and screwed it down to where the stock one was. Hopefully this works
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
    BLACK'98DSM likes this.
  8. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    Took me like 20 tries to get the car started. Doing the idle relearn now. Running for 5 minutes, shutting off. Nice easy drive for 20 minutes then shutting off
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
    BLACK'98DSM likes this.
  9. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    It's odd that it wouldn't start. I've started the car without an IAC at all. Let me know how that process goes and the results.
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
  10. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    It seems to have helped some, still having rough idle after the relearn. Keeps dipping down. The hesitation under load isnt present anymore but I wasn't WOT since I was on back roads
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  11. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  12. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    Looks like you have a vacuum leak somewhere. Have you inspected all of the hoses and ports?
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.
  13. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    The only one I haven't checked is evap, I believe that is what it is. The one on the top by the throttle body. I do have a large evap leak code. I'm thinking I can just cap off that port and see if that helps? I have no idea where that line is leaking at
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  14. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    I deleted the egr. Got some block off plates from the junk yard, I despise that system
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
    BLACK'98DSM likes this.
  15. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    Try just putting a vacuum cap on the port and then starting the car to see if it helps.
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
  16. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    Neither did I. That's why I deleted the system. It is nearly impossible to find a small leak in all this mess:

    EVAP - Edited.jpg
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.
  17. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    I have. No idea where this leak is coming from but I hear it behind the intake mani
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
    BLACK'98DSM likes this.
  18. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    Did you use a gasket or some sealant when you put the egr blockoff plate on the rear of the intake mani? if not, it is leaking.
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.
  19. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    Yes but the threading is stripped on the bottom bolt, I dont hear it or feel it leaking. Tried blowing smoke around and didnt see anything being sucked up
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  20. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    Does your car have cruise control? If so, check that little black reservoir that sits under the upper intake manifold. Mine was cracked and leaking vacuum. You can delete that by running the hose straight from the intake mani to the cruise control servo.
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.
  21. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    Yes it does. Maybe that's what I'm hearing
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  22. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    The biggest vacuum line on that tri-port is also cracked at the end. I think I need a new line for whatever that is
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
  23. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    Checked my vac lines from the mani, looks like it's the FPR vac line that has hardened and is splitting. Going to buy a new line today and replace it, see if that fixes my issue. Starting to make sense that is the source of the issue since it is responsible for monitoring my fuel pressure
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
    BLACK'98DSM likes this.
  24. 609DSM

    609DSM Proven Member

    183
    100
    Joined Aug 13, 2019
    Princeton, New Jersey
    So after seeing which vacuum line was the issue by unplugging one at a time and putting my finger on the port to see how it effected the engine, to my surprise it had no effect. It sounds as though the vacuum leak is from the egr port (the bottom threading has been really hard to get the bolt into since I started tinkering around).

    After doing all that I went to drive my car home and it was running surprisingly well, had full power and felt like a new car! I was confused though, didnt know what was going on. Soon after it just took a dump, when I came to a stoplight it wanted to stall out and was idling extremely rough and sounded like the exhaust was leaking.

    Not sure where I'm gonna go from here, cant realistixly drive it around...
     

    Street Build 224  1

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM
    Loading...
    BLACK'98DSM likes this.
  25. BLACK'98DSM

    BLACK'98DSM Proven Member

    1,312
    450
    Joined Feb 9, 2019
    Hoover, Alabama
    So the only CEL is for evap?
     

    Road Race Build 2K  23

    1998 Mitsubishi Eclipse N/T
    fwd · manual · 2G DSM

    496  5

    2012 Murray Explorer Dune
    rwd · automatic · Misc Vehicles

    388  4

    2009 Troy Bilt Bronco
    rwd · automatic · Misc Vehicles
    Loading...
    609DSM likes this.

Share This Page

Support Vendors who Support the DSM Community
Archer Fabrication ECM Tuning ExtremePSI Feal Suspension Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications OHM Racing RixRacing RockAuto SouthBay Fuel Injectors STM Tuned Track Decals Track Sculptures VR Speed Factory WheelWell.com