Page 4 of 4 FirstFirst ... 234
Results 31 to 40 of 40

Thread: 100,000 mile compression test/spark plug replacement!

  1. #31
    Senior Member
    Join Date
    Aug 2017
    Location
    SW, WI
    Country
    United States
    Posts
    7,402
    Thanks
    594
    Thanked 2,688 Times in 2,106 Posts
    Quote Originally Posted by Fummins View Post
    I've never indexed spark plugs except for in diesels.
    I find that very interesting!



  2. #32
    Senior Member
    Join Date
    Apr 2018
    Location
    Atlanta Metro
    Country
    United States
    Posts
    3,523
    Thanks
    37
    Thanked 1,389 Times in 1,007 Posts
    Note to self: Remove the antenna...

    My Cummins is always fouling spark plugs so I have to change them freqently.

        __________________________________________

        click to view fuel log View my fuel log 2020 Mirage ES 1.2 manual: 42.4 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.9 mpg (Imp)


  3. #33
    Senior Member
    Join Date
    Aug 2017
    Location
    SW, WI
    Country
    United States
    Posts
    7,402
    Thanks
    594
    Thanked 2,688 Times in 2,106 Posts
    Quote Originally Posted by 7milesout View Post
    No, I haven't done it to the Mirage yet. I figure out how much rotation it takes to bend the metal gasket thingie to reach set torque. And if it's out of position when I meet the metal gasket thingie before bending it, I swap it to the next cylinder. It will be more difficult to do it right on a Mirage since we only have 3 cylinders. In the end, it's not worth it. But I can't help being a friggin nerd about it.
    I think a person would need a set of washers with different thicknesses to pull it off. They would act as shims, but then you may have the risk of not having your spark plug seated down far enough (creating a whole new problem).

    Fummins - So rockauto.com list factory OEM NGK spark plugs for $6.16/plug, but you can only buy them in pack of 4 for that price. You can't change your checkout cart to 3 plugs. I find that a bit stupid, but that doesn't bring up my questions here.

    As I look at the plugs in the checkout cart (wanted to see what shipping would have been), this notice comes up -

    "Manufacturers recommend replacing Spark Plug / Coil-On-Plug Boots when replacing Spark Plugs."

    Spark plug boots for a Mirage are $3.57/boot @ rockauto.com.

    Have you or anyone seen this manufacturer suggestion?

    Have you or anyone had an issue their coil-on-plug boots?

    Seems like a notice I would ignore, but wonder if this has been an issue for anyone? I don't see myself doing my first plug change for another 4 years or so.
    Last edited by Mark; 05-17-2021 at 08:48 PM.

  4. #34
    That's dumb. We sell individual spark plugs at work.

    I've only replaced plug boots if they're cracked,torn or soaked in oil. I've never had to replace any on the Mirages yet. But...one of the shops that services our cars out of town claimed a Mirage needed spark plug boots. So I sent them a set from an engine I had on the floor and asked for the old ones back. I didn't see anything wrong with them at all. No cracks, not dried out. Just a waste of time and money I guess.

        __________________________________________

        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)


  5. The Following User Says Thank You to Fummins For This Useful Post:

    mohammad (07-22-2022)

  6. #35
    Quote Originally Posted by 7milesout View Post
    Note to self: Remove the antenna...

    My Cummins is always fouling spark plugs so I have to change them freqently.
    Glow plugs too, they're always plugged with blinker fluid.

        __________________________________________

        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)


  7. #36
    Senior Member
    Join Date
    Apr 2018
    Location
    Atlanta Metro
    Country
    United States
    Posts
    3,523
    Thanks
    37
    Thanked 1,389 Times in 1,007 Posts
    I had a set of spark plug boots crack immediately upon changing spark plugs on a 1990 Toyota Celica. I didn't know what the problem was, as the boots seemed fine during the spark plug change. Took it to a shop, they told me the boots were arcing to the head / valve cover. Luckily, they didn't charge me just to find the problem. I took it home and put 4 new spark plug wires / boots on it and back to running like a champ. Course ... it did have probably close to 200k miles on it at that time. Not a drop of oil down in there. It just stayed dry and cycled from ambient to hot for 200k miles. Guess it dried out the boots and made them brittle.

    I can see why a manufacturer might recommend such a thing. But I think it could just be monitored and replaced as needed.

        __________________________________________

        click to view fuel log View my fuel log 2020 Mirage ES 1.2 manual: 42.4 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.9 mpg (Imp)


  8. #37
    Member
    Join Date
    Feb 2022
    Location
    Holden Beach North Carolina
    Country
    United States
    Posts
    46
    Thanks
    4
    Thanked 32 Times in 12 Posts
    Quote Originally Posted by Cobrajet View Post
    Well, 97,516 miles to be exact.

    I always wondered how this engine was holding up to what I was subjecting it to, and decided that if I was going to have the plugs out for replacement anyway I might as well do a compression test. Technically, the plugs are not due for replacement until 105,000 miles. But I also decided that if I was going to check the condition of the engine it should be done just before the warranty expires, not just after.

    You will need:

    1) Compression tester. These can be rented at any auto parts store.
    2) Ratchet.
    3) 10mm socket.
    4) Spark plug socket (the smaller one of the two).
    5) 6" ratchet extension
    6) Replacement spark plugs. I went with the Denso IKH16TT.
    7) Silicone dielectric grease.
    8) That's it!



    The compression test should be done with the engine HOT OR WARM, since this is it's normal operating condition. So warm the car up.

    The first thing you will remove is the baffle on the side of the air cleaner housing. There is one 10mm bolt that holds it on, and you should be able to wiggle it out of the side of the housing by pulling it to the left.



    The next thing you will remove is the air cleaner housing. There is one bolt on the left side..



    ...and one on the back.



    The air cleaner housing can be separated and the filter removed. The rear section of the housing is secured on the bottom to the top of the valve cover by a rubber grommet. Wiggle it up and out.



    The PCV hose is clipped onto the right side of the air cleaner housing. Simply pull it free.



    The intake hose can be removed with the 10mm socket by loosening the lower clamp. Pull it free.



    There is one electrical connector to disconnect at the housing for the Intake Air Temp Sensor...



    The front of the air filter housing can be swiveled out of the way and rested on the battery, or you can disconnect the PCV hose with pliers and remove it completely. The coil packs should now be visible. Each is retained with one 10mm bolt, painted orange.



    Remove the coils by removing the bolts and disconnecting each of them. Wiggle them up and out. I would keep them in the order they were removed so they can be reinstalled on the cylinder they came off of.



    Removing the spark plugs is pretty self-explanatory. Just unscrew them. If you are planning to replace them they can be discarded. If you are going to reinstall them, keep them in order so you can put them back into the appropriate cylinder.

    Once all have been removed, disconnect each fuel injector connector at the fuel rail. This will keep the PCM from fueling the cylinder, as excessive fuel in the cylinders during the test will wash the cylinder walls and affect the readings.



    Okay, you are ready to start the test! Screw the tester securely into the #1 spark plug hole. Get into the car, FLOOR THE ACCELERATOR, and crank the engine over about ten times. You need to floor the accelerator to allow the throttle body to open wide and allow as much air to enter as the cylinder needs.

    You should get a reading like this on the tester...



    ...and #2...



    ...and #3.



    And there you have it! On my motor the results are read as:

    Cylinder #1: 195 psi
    Cylinder #2: 195 psi
    Cylinder #3: 190 psi.

    Factory specs are 205 psi for a new motor. The readings here indicate that at the end of my powertrain warranty this is still a healthy motor! This engine got no Superman maintenance...just by the book. Mobil 1 0w-20 AFE full synthetic every 7,500 miles...religiously. Plugs looked like you would expect 100,000 mile plugs to look.



    Reassembly is the reverse of disassembly. My coils were sticky coming off, so I put some dielectric grease in the ends when reinstalling them.

    When I started the car after reassembly, the check engine light was on. It gave me a code P0113, which is for the disconnected IAT sensor. I am not sure if this code will self-resolve over time, but I just reset mine with an OBDII reader. Any auto parts store will reset the code for free.





    And there you have it. Please post up your readings if you do a compression test. Let's see how tough these little three-holers are.
    Bought a 2015 ES automatic at auction on Tuesday, had 105,000 miles, spark plugs looked the same as pictured, so I assume that they had never been changed. Did compression test
    1. 155psi
    2. 150psi
    3. 160psi

    Not close to your 190s but minimum according to mitsubishi is 138psi so I guess I can't be too sad.

    According to carfax service history was regular. I started this because I drove the car today delivering pizza and only got 27mpg and all my other mirages get 40+, so I suspected a spark plug or compression problem, not sure if new plugs will help but we will see.

  9. #38
    Senior Member Cobrajet's Avatar
    Join Date
    May 2015
    Location
    Olympia, WA
    Country
    United States
    Posts
    3,126
    Thanks
    1,197
    Thanked 1,848 Times in 1,101 Posts
    Quote Originally Posted by hkpotts1 View Post
    Bought a 2015 ES automatic at auction on Tuesday, had 105,000 miles, spark plugs looked the same as pictured, so I assume that they had never been changed. Did compression test
    1. 155psi
    2. 150psi
    3. 160psi

    Not close to your 190s but minimum according to mitsubishi is 138psi so I guess I can't be too sad.

    According to carfax service history was regular. I started this because I drove the car today delivering pizza and only got 27mpg and all my other mirages get 40+, so I suspected a spark plug or compression problem, not sure if new plugs will help but we will see.
    Did you check the compression with the engine hot?

  10. #39
    Member
    Join Date
    Feb 2022
    Location
    Holden Beach North Carolina
    Country
    United States
    Posts
    46
    Thanks
    4
    Thanked 32 Times in 12 Posts
    Quote Originally Posted by Cobrajet View Post
    Did you check the compression with the engine hot?
    Yes the engine was still warm I delivered pizza all night then came home and waited 30 minutes then did the spark plugs and compression test.

  11. #40
    Senior Member
    Join Date
    Nov 2015
    Location
    Festus, Missouri
    Country
    United States
    Posts
    120
    Thanks
    22
    Thanked 62 Times in 39 Posts
    Adding some data on these cars. 2015 DE with cvt transmissions 172,000 miles on odometer. #1 182 psi #2 179 psi #3 185 psi. Regular oils changes per manufacturer (with some extended runs due to laziness).


        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 automatic: 46.2 mpg (US) ... 19.6 km/L ... 5.1 L/100 km ... 55.5 mpg (Imp)


  12. The Following 4 Users Say Thank You to jbarr For This Useful Post:

    Cobrajet (08-21-2022),davidricardo86 (04-14-2023),inuvik (08-22-2022),Wil B (08-20-2022)

Posting Permissions

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