Cyl 1 Misfire Code, Mechanic recommending head work?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Fingers04501, Jan 14, 2016.

  1. Fingers04501

    Fingers04501 Junior Member

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    Howdy all! Brand new member here, so if this has been answered somewhere already, I'm sorry.I have a 2008 with about 184K miles that has consistently read a cyl 1 misfire code for a few weeks. engine shudder at startup/idle/shutdown is getting progressively worse, along with a big decrease in MPG. I went ahead and did spark plugs, and a coil pack on cyl 1, Cleaned the Mass Airflow Sensor (using MAS cleaner), have ran 2 bottles of fuel treatment/FI cleaner through 2 consecutive tanks, and have been using "name brand" gas for the last 5-7 tanks. (all at the recommendation of other threads on this site, thanks guys!) Now a mechanic that I pretty well trust is recommending a minimum of 2000 bucks worth of work to open the head and look for a problem. Based on what I've read here, injectors and Fuel Pressure Regulator may be a better thing to look into before dropping that kind of money into it. What I can't find anywhere is how difficult it is to get to the injectors? I am not a great mechanic, more in the "willing-to-learn hobbyist" category, but my father is a pretty good tinkerer and seems to think we can do this in a few hours in the garage. Thoughts? Advice?
     
    #1 Fingers04501, Jan 14, 2016
  2. bisco

    bisco cookie crumbler

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    welcome! surprising that a good mechanic wouldn't be able to do more testing before opening her up. compression test?

    before you spend $2,000. on a research trip, consider swapping for a low mile used engine. probably around the same price.
     
    #2 bisco, Jan 14, 2016
  3. Fingers04501

    Fingers04501 Junior Member

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    thats kind of what it thought too. im not really planning on doing head work until i rule out a few more things. any idea how difficult injectors are to get to on this engine?
     
    #3 Fingers04501, Jan 14, 2016
  4. Dion Kraft

    Dion Kraft Member

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    #4 Dion Kraft, Jan 14, 2016
  5. Toppcat

    Toppcat Member

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    Find a more knowledgeable prius mechanic, cut down on guess work! 1.Electronic balance test 2. Dry\wet compression and leak down test. question is weather it's worth dumpimg $2,000+ into a vehicle with high mileage?
     
    #5 Toppcat, Jan 14, 2016
  6. Dion Kraft

    Dion Kraft Member

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    Now that we know it is NOT a spark problem injector replacement is the next step. But also you need to also take in a compression check to see if the cylinder itself is not low to cause all this. If the compression is low then you need to insert some oil to see if the rings themselves are the problem or the valves are leaking. If compression goes up then rings after oil is injected in the cylinder. Another future problem that exists is damage to the Cat converter if there is a prolong time of missfire with too may hydrocarbons (too rich) streamed down to the CAT.
    If you repair this missfire early on then you can save it. For those who linger...well the end result is the cat replacement. Good luck.
     
    #6 Dion Kraft, Jan 14, 2016
  7. Fingers04501

    Fingers04501 Junior Member

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    That is super helpful. I believe that is going to be my next step. even 4 new ones will cost less than the parts alone were quoted! I think i just found my weekend project. thanks!

    yeah, its sitting now while i figure out what to do, CAT's are expensive, so its worth driving the backup vehicle for a while. are compression testers relatively cheap or is that something to get a shop to do?
     
    #7 Fingers04501, Jan 14, 2016
    Last edited by a moderator: Jan 14, 2016
  8. Dion Kraft

    Dion Kraft Member

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    You can pick them up fairly cheaply. From Harbor Freight to Snapon...you decide on the price point
     
    #8 Dion Kraft, Jan 14, 2016
  9. Fingers04501

    Fingers04501 Junior Member

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    So after replacing the injector only on cylinder 1, CEL is gone. Cautiously optimistic that we have found the problem! have driven it in several weather conditions over the weekend, runs much smoother. Thanks for the step-by-step link you sent me. It made the whole thing about an hour job.
     
    #9 Fingers04501, Jan 19, 2016
  10. Dion Kraft

    Dion Kraft Member

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    Thanks good everything ended well!
     
    #10 Dion Kraft, Jan 19, 2016
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