Spark plugs

Discussion in 'Honda Hybrids' started by Alansr, Nov 23, 2014.

  1. Alansr

    Alansr Member

    I was thinking of upgrading the spark plugs on my HCH because it is an 08 and I have put 13,000 miles on it since I bought it.

    Do you guys have any suggestions?
  2. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    I would just use the stock spark plugs. There's two spec'd in the Owners Manual:

    ILFR6J-11K (NGK)
    SK20HPR-L11 (DENSO)

    Some instruction from the Service Manual:

    There are 8 plugs to be replaced, and if I recall correctly, to access to the rear bank of plugs you're pretty much forced to remove the lower windshield cowl. I did that for a valve tappet inspection, here:

    When I first had a look at ours I discovered there were four Denso's and four NGK's in there. When I replaced I used just NGK. Also, if you ever opt to clean and re-install them, don't use sandblast, they're somewhat fragile. I used carburetor cleaner and an old toothbrush.
  3. S Keith

    S Keith Well-Known Member

    "upgrading"? Heck no.

    Have you checked the prices on the OEM units? They'll run you about $14 each from a parts store or $20 from the stealership. Hard to spend more than that. :)

    The consensus is to stick with the OEM plugs. They're already premium Iridium, platinum and unobtainium :)

    Don't bother replacing them until you have 100K miles.

    If your '08 HCH2 is like my '06 HCH2, I didn't have to remove the lower windshield cowl; however, the rear coil pack closet to the driver was a bit tricky to get out.

    Two of the ~3" ratchet extensions are about perfect. Put your plug socket on one, lower it into the chamber, add the extension and seat the socket on the plug. Attach the ratchet, and you're good to go.

    I had a similar situation as Mendel - 4 denso in the rear, 4 ngk in the front. Replaced with NGK only on both HCH2 I own.
  4. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    If S Keith managed to avoid cowl removal, I'd retract my suggestion then.

    What's your Odometer showing, what's the total miles (or kilometers) on it? The simplest way to make decision is to just follow the Maintenance MInder, I believe it prompts to change plugs and valve clearance at the same time. Then I believe you will need to remove the cowl, but for spark plugs alone I guess not. FWIW, cowl removal is not that hard. The Prius requires similar cowl removal, even for simple spark plug removal, and it is a bear!
  5. S Keith

    S Keith Well-Known Member

    Method of cowl removal wasn't obvious to me after an ADHD 5 seconds of effort, so I skipped it. It was a very tight fit, required careful positioning, rotation and very slight bending to get the coil pack out and in (only the one rear, leftmost from driver seated position).
  6. Alansr

    Alansr Member

    Thanks for the info.
    Since mine only has 38K on it I'll wait for a while before spending that kind of money without any gain.
  7. S Keith

    S Keith Well-Known Member


    I just did the math... you have a 6 year old car with only 38K miles on it... a little over 6K miles per year. I know you're driving the snot out of it now, so that's good. My concern is that the low amount of driving prior to your ownership contributed to cell imbalance.

    I have a very strong opinion about the HCH IMA system. It is NOT like any other car system that can just be ignored. As far as Honda is concerned, all you do is don't let it sit too long and then come in for a battery replacement when the IMA light comes on. The IMA battery is like your car's oil. It is an important part of the drive system that requires maintenance.

    You are covered by the 9 year, 92K miles warranty (unless you're in one of the other states that offers a greater warranty), so you have a lot of warranty left, but with your commute, you'll probably hit the mileage limit before you pass the 9 year mark.

    At that time, I would encourage you to engage in regular battery maintenance. This can be done by using a grid charger - a homebuilt ($100) or commercial ($400) charger powered by the grid that slowly tops off your pack (over a 24 to 32 hour period). The best of the aftermarket new pack suppliers recommend quarterly grid charging to top off the battery, which balances all the cells at a true 100% state of charge (SOC). This practice can extend the life of the battery for years.

  8. Alansr

    Alansr Member

    The original owners bought it to drive around town to save gas on their SUV's. Then their son drove it to school and around town. So it was used on a fairly regular basis just all in stop and go traffic and only a very few long trips of 100+ miles. Now, I'm putting 1000 miles a week on it.
    I'm very good with the preventative maintenance so I feel pretty good about the car. Especially, since I've read such great reviews on the car.
    Also the original owners had the hybrid batteries replaced about 2 months before I bought it.

    Does the warranty transfer since I'm not the original owner?
  9. S Keith

    S Keith Well-Known Member

    I believe it does, and the fact that it was replaced this early in its life supports my suspicion that the battery was in a bad state of imbalance.

    You must have missed the massive number of reviews slamming the battery performance... :)

    Preventative maintenance is what I'm talking about. There isn't any on the IMA battery. There should be. Even with your driven miles, I still encourage you to start doing quarterly grid charges after your warranty is out.

    I may sound negative, but keep in mind that I have two '06 HCH2 and 4 battery packs between them... I'll be running these things into the ground, and I'll be happy the whole time :)

  10. HCH2007

    HCH2007 Journeyman Hypermiler


    Exactly how would I build the homemade grid charger? I'm all about saving money especially on a fixed income (Veteran Disability Compensation). I'm very handy at building electric and electronic devices and would like to give this a shot.
  11. S Keith

    S Keith Well-Known Member

    Probably want a fuse on the A/C side. I have found that these supplies don't have any issue with being connected to a live pack before energizing.

    You'll need to build or buy a PWM controller for the 12V IMA fan. Guy on eBay has one for $50 or Peter Perkins over at Insight Central sells a blank PCB for $20 shipped from UK with another $13 or so in bits from digikey. Peter also has fully assembled ones, but with shipping they're over $65 IIRC. If you go the blank PCB route, you'll need to be able to program a controller. If not, Peter can sell you a USB dongle that can program the PIC with his code.

    Since my prior recommendation, I've embraced deep discharging:

    1. Do a triple 12V reset to have the car max out the pack
    2. Grid charge to peak voltage (do not charge in-car without running the IMA fan).
    3. Discharge with 2X 200W bulbs in series to 120V
    4. switch to 2X 60W bulbs until you flatten the pack, <2V.
    5. Grid charge for just a few minutes until the pack will hold >120V
    6. Repeat the triple 12V reset to have the car charge the battery 3 times. First one will take a long time, third one almost none.
    7. Grid charge to peak V.
    8. Drive.

    Discharger can simply be a couple of cheap ceramic lamp holders from home depot screwed to a 2x6 with a HF DVM in parallel for voltage and another in series on the 10A setting to view current. You can video the discharge and compute your mAh capacity.

  12. S Keith

    S Keith Well-Known Member

    Okay. Third time is a charm. Reported.
  13. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi SKeith:

    He is gone. :)

  14. S Keith

    S Keith Well-Known Member

    Thanks Wayne.

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