Page 1 of 6 123 ... LastLast
Results 1 to 10 of 57

Thread: Massive misfire cylinder 1 -- SOLVED (wire corrosion)

  1. #1
    Senior Member Rkt Ship's Avatar
    Join Date
    Jan 2014
    Location
    Mansfield, Oh
    Country
    United States
    Posts
    384
    Thanks
    22
    Thanked 188 Times in 79 Posts

    Massive misfire cylinder 1 -- SOLVED (wire corrosion)

    I ran into an issue last night. I was on cruise control going down 71 and I started getting a massive misfire. It felt like I lost a cylinder. I immediately pulled over and had the car towed home. I was flying blind as my Bluetooth obd reader was in my wife's truck so I started checking things that could cause misfire. I pulled spark plugs. They looked pretty beat so figured why not replace. No fix. I took the spare could that were known good at one time and swapped them in. No dice. I then moved to injectors. Once I swapped out the newer injectors from when I bought the engine. Everything seemed fine. Then this morning I went to leave it felt ok then about a mile from my house I lost power and lost a cylinder again. Check the one reader and I have misfire cylinder 1. Now I checked the Injector resistance and they were at about 12.5 ohms across the board. I then checked the wires to see of there was any voltage drop. I found 12v on one side and 2.5v on the other across the board. I think with the key on it's "priming" the injectors which is why there's 2.5 on one side. If you pull a connector and check codes you'll get a pending injector low voltage code. If you plug it back in it goes away. After coming up what seems to be good there I moved to the scary stuff. Draining the oil to look for bearing material. I had no bearing material in the oil nor any metal shavings stuck to my drain plug magnet. Just to play it safe I ran the oil through a paper towel to try and find some material. No material. I also ran a magnet through and cut open the oil filter to check for stuff and nothing. Now I'm confused as to where to go from here. I guess I could pull the valve cover and see if there are any valves stick open. That's a pretty quick check. Other than that I'm lost. Any advice would be great. Thanks in advance.



    Quote Originally Posted by Rkt Ship View Post
    Now onto the real problem. It was corroded wiring. Like really corroded. The wire had chaffed in the tab that holds the injector harness to the intake manifold.
    Quote Originally Posted by Rkt Ship View Post
    Another wire that had rubbed through on the plastic connector that mounts the harness to the manifold. This one had rubbed through completely when I opened up the harness it was in 2 pieces.



    Last edited by Eggman; 07-19-2021 at 07:47 PM. Reason: Added solution

  2. #2
    Senior Member Top_Fuel's Avatar
    Join Date
    Feb 2016
    Location
    Ohio
    Country
    United States
    Posts
    3,699
    Thanks
    2,582
    Thanked 2,537 Times in 1,471 Posts
    Quote Originally Posted by Rkt Ship View Post
    ...I started getting a massive misfire.
    ...It felt like I lost a cylinder.
    Was the check engine light flashing when this happened?

    Check the one reader and I have misfire cylinder 1.
    You didn't mention anything about checking ignition coils?

    Try this... Swap the coil from cylinder #1 to another cylinder, reset the codes, and drive it. If the misfire code moves to another cylinder, you have a bad coil.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 52.2 mpg (US) ... 22.2 km/L ... 4.5 L/100 km ... 62.6 mpg (Imp)


  3. The Following 2 Users Say Thank You to Top_Fuel For This Useful Post:

    Cobrajet (11-16-2017),Daox (12-21-2017)

  4. #3
    Senior Member Rkt Ship's Avatar
    Join Date
    Jan 2014
    Location
    Mansfield, Oh
    Country
    United States
    Posts
    384
    Thanks
    22
    Thanked 188 Times in 79 Posts
    Quote Originally Posted by Top_Fuel View Post
    Was the check engine light flashing when this happened?



    You didn't mention anything about checking ignition coils?

    Try this... Swap the coil from cylinder #1 to another cylinder, reset the codes, and drive it. If the misfire code moves to another cylinder, you have a bad coil.
    Yeah the scary blinking check engine light happened.

    I swapped in a good set of coils. Autocorrect changed it to could.
    Just checked compression. I have 180 across the board. Ugh.

  5. #4
    Senior Member Rkt Ship's Avatar
    Join Date
    Jan 2014
    Location
    Mansfield, Oh
    Country
    United States
    Posts
    384
    Thanks
    22
    Thanked 188 Times in 79 Posts
    Im following mitsubishis protocols in the fsm and it says if its not the ignition components or the compression then its the ecm. It doesnt even take you through fuel stuff to check. Does that seem weird to anyone else?

  6. #5
    Senior Member Top_Fuel's Avatar
    Join Date
    Feb 2016
    Location
    Ohio
    Country
    United States
    Posts
    3,699
    Thanks
    2,582
    Thanked 2,537 Times in 1,471 Posts
    Assuming the misfire is always on cylinder #1...

    Swap the #1 injector to cylinder 2 or 3...clear codes...test drive. Does the misfire code now indicate another cylinder is now misfiring?

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 52.2 mpg (US) ... 22.2 km/L ... 4.5 L/100 km ... 62.6 mpg (Imp)


  7. #6
    Senior Member Rkt Ship's Avatar
    Join Date
    Jan 2014
    Location
    Mansfield, Oh
    Country
    United States
    Posts
    384
    Thanks
    22
    Thanked 188 Times in 79 Posts
    Quote Originally Posted by Top_Fuel View Post
    Assuming the misfire is always on cylinder #1...

    Swap the #1 injector to cylinder 2 or 3...clear codes...test drive. Does the misfire code now indicate another cylinder is now misfiring?
    I swapped 3 good injectors in. Then Just in case I moved them around. Cylinder 1 has been the problem the whole time.

  8. #7
    Senior Member Rkt Ship's Avatar
    Join Date
    Jan 2014
    Location
    Mansfield, Oh
    Country
    United States
    Posts
    384
    Thanks
    22
    Thanked 188 Times in 79 Posts
    it even got to a point where I was questioning which cylinder is #1.

  9. #8
    Senior Member
    Join Date
    May 2014
    Location
    Country is Europe, state is Germany
    Country
    Germany
    Posts
    1,713
    Thanks
    234
    Thanked 1,158 Times in 670 Posts
    Often its the small stuff that gets overseen and gives you a hard time.

    If you want to check if a valve isn't closed, you could pull out the injector and stick a litte USB endoscope down the injector hole.
    On the other hand, if a valve is not closed, compression is gone. If it starts OK and suddenly don't run right, it doesn't look like an open valve.

    It could be something simple, like a corroded plug/socket in a cable assembly inside, on the left side and below the dash. The wires from the ECU go from there via another plug/socket to the injectors.

  10. The Following User Says Thank You to foama For This Useful Post:

    MightyMirageMpg (11-17-2017)

  11. #9
    Sorry to hear your having problems! Do you have a constant missfire at idle or does it go away when revved up or does it only miss under load?
    Mirage videos:

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  12. #10
    Senior Member Rkt Ship's Avatar
    Join Date
    Jan 2014
    Location
    Mansfield, Oh
    Country
    United States
    Posts
    384
    Thanks
    22
    Thanked 188 Times in 79 Posts
    Quote Originally Posted by Fummins View Post
    Sorry to hear your having problems! Do you have a constant missfire at idle or does it go away when revved up or does it only miss under load?
    It's all the time.



Posting Permissions

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