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. ;)

Running on cylinders 3 and 4. All possible causes?

Posted by v8s_are_slow, Aug 2, 2013

Please Support JNZ Tuning
Please Support STM Tuned
  1. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    Just spent from the end of May to yesterday trying to figure out why my AEM wideband wasn't showing the proper voltage on Link. It was a bad wideband and ended up trashing it and getting an Innovate DB gauge. Finally got it up and running yesterday, idling real good, then I shut it off. Come back to fire it up and do more tuning and it's only running on cylinders 3 and 4. Well, after disabling injectors 1 & 2 and no change, then both 3 &4, both of those made a difference in how the car ran.

    I really don't wanna spend forever on THIS problem too just to try and diagnose the issue. Wanna make this quick cause I wanna be driving my car again next week. So I'm wondering what all could cause the problems, and how to test each item to narrow it down. Please dumb it down some for the electrically stupid.

    Items I know of so far would be coil pack, power transistor, cas (maybe?) and cps (maybe, again?), bad wiring, and ecu. Thanks for any input into this.
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  2. killercolt

    killercolt Proven Member

    294
    20
    Joined May 23, 2008
    Acworth, Georgia
    If you have a black cas, that might be your problrm
     
  3. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    I don't. It's the stock, non-adjustable cas for a 98.
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  4. boost97gst

    boost97gst Proven Member

    2,803
    128
    Joined Apr 2, 2012
    st jacob, Illinois
    So the plugs are wet right? I mean, do you know for sure its not getting spark? Im having a sort of similar problem right now. Traced it down to what i believe is the injector drivers in the ecu. Its just self-punishment owning one of these cars right? LOL.

    No spark is going to be cas,cps,ptu, coil, wires, plugs. Thats pretty much it
     
  5. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    Didn't think about that. I guess when I get home in about an hour, I'll be pulling the plugs and try and fire it up. I've usually just had all the fuel shoot out the spark plug holes when there's no plugs installed. So guess that'll tell me. May just need a volunteer to watch the motor for me while I'm doing it though.

    Sure hoping it's not the ecu though. I JUST sent it off to Tom and Dave at Ecmlink to have it checked out for me since my wideband was all screwy. I was checking EVERYTHING!!! Would hate to have to send it back....again. I'll post an update though. Crossing fingers.
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  6. boost97gst

    boost97gst Proven Member

    2,803
    128
    Joined Apr 2, 2012
    st jacob, Illinois
    Dude, tell me about it. I have had random injector problems on inj #3 since i sent mine off to get socketed. Coincidence? Probably. DSM luck? Definitely.

    Way i see it: The cas/cps send signals to the ecu which in turn sends signals to the gate(s) in the ptu thus applying primary voltage to the coil pack. It would seem to me if either the cas or cps wasnt functioning you wouldnt be getting spark OR fuel on all 4. Id be leaning towards ptu or coil. Just my 2 cents.
     
  7. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    Okay, all cylinders are getting fuel. So I guess it's not the ecu. Swapped out the plugs and the miss stayed with the same cylinders, so that rules out the plugs. I had a spare coil pack and transistor so swapped those out but still the same problem....unless the parts I used are bad as well.

    I read this thread (http://www.dsmtuners.com/forums/articles-electrical-wiring/229419-how-test-power-transistors.html) but I have no clue what he's saying about the batteries. Hook them both up to pin 3 on the harness side? Transistor side? One battery one the harness side, and the other battery to the transistor side? I have no clue what he's saying to do, so have no idea how to test it.

    Cas and cps is still to be determined as well.
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  8. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    Anyone with any info on how to test the cas/cps, or a better explanation on testing the transistor than the link above?
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  9. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    Anyone???

    I've read that you can turn the cas by hand and listen for the injectors pulsing, but I didn't hear crap. However, I dunno if that test works on a 97-99 type cas or not. Who knows.
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  10. Night devil

    Night devil Proven Member

    61
    0
    Joined Apr 12, 2013
    Windsor, ON, Canada
    Check if your getting spark on all of them. If your only getting spark on two not four most likely its one of your sensors. I could be mixing up with this, left side of the coil pack is for crank sensor and right side is for your top left (cas) sensor. Check if these two sensor are not broken or a wire cut off.
    To test which side it is:
    Unplug the cas clip see if theres a change, if there is then its good. If not then that sensor needs to be changed. For crank sensor (no timing cover has to be off) unplug the crank sensor clip on the right side if your looking at the motor behind the timing belt cover. Try to turn on the car and see how it goes. Samething if it changes then its working fine if not needs to be changed .
    Good luck and let us know how it goes
     
  11. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    I sure feel like an idiot. This is too easy and have no clue why I didn't think of it. I'm sitting here thinking, "Use multimeter or test light and probe this pin or that pin or what?" Ugghhh, I feel dumb, but thanks for pointing out my dumbness ;)

    So I disconnected the cps while running and it died. So cps is good.

    Disconnected the cas a few times. Sometimes it'd have no effect. Sometimes it'd hesitate slightly but keep running. So guess the cas, or power transistor. Only wonder because when disconnecting the cas, it'd hesitate. I'll post up results when I have the problem fixed though. Hopefully later today.
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  12. Night devil

    Night devil Proven Member

    61
    0
    Joined Apr 12, 2013
    Windsor, ON, Canada
    It's not dumbness, sometimes you think of big stuff and forget the simple stuff. It happens all the time LOL. Best of luck and let us know how it goes :)
     
  13. v8s_are_slow

    v8s_are_slow Proven Member

    2,236
    104
    Joined Sep 30, 2002
    Panama City, Florida
    Okay, no luck with anything yet.

    Changed both the transistor and cas, and no change. I have a spark tester that I put between the wire and the plug. All cylinders are getting spark. I even pulled all the plugs and each one is wet but I decided to get new plugs anyway. All gapped at .028 with BR7ES plugs, still the same problem.

    I flipped the cas 180 just to be sure. Still the same problem. When I disable injectors 3 and 4 in Ecmlink, the car dies. 1 and 2, no change.

    So odd.

    Figured it out. I had changed the coilpack and when I did, I used the stock firing order, when I'm suppose to use the non-95/96 cas with 95 ecu. Duh me. But so happy it works properly now :)
     

    2K  20

    1998 Mitsubishi Eclipse GST
    10.949 @ 129.77 · 2G DSM
    Loading...
  14. Night devil

    Night devil Proven Member

    61
    0
    Joined Apr 12, 2013
    Windsor, ON, Canada
    Good to hear you figured it out. Thanks for posting the solution.
     

Share This Page

Support Vendors who Support the DSM Community
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