Terrible engine sound prius 2008 (fault code: P0304)

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by subhash, Mar 11, 2022.

  1. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    Two weeks back my 2008 Prius engine started to make crazy noise and vibration in the middle of a drive. I saw the check engine light flashing. I did not know what that meant then so i drove last 3 miles very slowly to reach my home. Google top result for the symptoms is engine misfiring. So i replaced all the spark plugs i was very careful and i think the replacement went alright. I turned on the engine unfortunately the problem is not fixed. The video included is after the spark plug change.





    I bought a OBD scanner the error codes are

    P0304 (fault code): cylinder 4 misfire
    P0138 (pending code) : O2 sensor issue.
    Most of the comments on the video posted on r/prius subreddit were "engine broke". What do you think? Is the engine really broke? The car has 140K miles on it. I really hope the engine is not broke.

    Suggestions from reddit were:
    1. Swap the ignition coils see the code changes to a different cylinder. If yes replace the ignition coil
    2. Clean the fuel injectors
    3. Replace the head gasket and PCV valve

    I am trying to do most of the things i could possibly do before i get a mechanic to fix it. Do you think this problem is fixable?
    Any suggestions are appreciated.
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    101,159
    45,865
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    does the car burn any oil?
     
  3. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    I am not sure. How will i know that?
    It consumes more oil. I have one quart spare just in case if the level goes below. But its not to a absurd amounts.
     
  4. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    8,809
    3,609
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    What is the oil level at? Has it been low for a long time?
    Let us know what happens after moving around ignition coils to determine if misfire moves to different cylinder or not?
     
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    101,159
    45,865
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    if the oil level drops on the dipstick between oil changes, it is burning oil. you can track it if you wish by googling the dipstick measurement from high to low and how many quarts it equals
     
    PriusCamper likes this.
  6. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    8,809
    3,609
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    Always love it when you start preaching about dipsticks!
     
    bisco likes this.
  7. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    101,159
    45,865
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    let's not get thrown into the politics thread :p
     
    PriusCamper likes this.
  8. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    I erased the logged fault codes swapped the coils 1 and 4. Restarted the engine had to run it for 2 to 3 minutes for the check engine light to show up. Once i saw the blinking check engine light i stopped the car. Then checked the fault codes again. This time it showed all the 4 cylinders misfiring [P0300, P0301, P0302, P0304]. This is really weird how swapping 1 and 4 caused this. I thought i may have done something wrong when i installed the spark plugs but the hybrid got charged during this time. If the issue was with spark plugs that should not have charged the hybrid battery correct?
    What do i do now? Check fuel injectors?

    It never dropped below the lowest dot. Recent oil change was on the last week of December 2021. Right now the oil level is little over the maximum dot on the dip stick. Also i added reply what happened after swapping the coils. Please have a look at that.
     
    #8 subhash, Mar 12, 2022
    Last edited by a moderator: Mar 12, 2022
    bisco and PriusCamper like this.
  9. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    8,809
    3,609
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    Maybe next step is doing a compression test in maintenance mode?
     
  10. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    Thanks, I will look into it. How do i know compression is good or bad? Do you know the numbers for prius gen2?
    If it turn out bad can it be fixed or engine is broken?
     
  11. BuyJapanese

    BuyJapanese Member

    Joined:
    Jun 12, 2019
    61
    28
    0
    Location:
    Wisconsin
    Vehicle:
    2005 Prius
    Model:
    II
    I don't know if there are factory spec numbers for compression on a new engine, but that wouldn't matter anyway. Piston ring and valve seal wear over time will always reduce compression but the engine will still run well if all cylinders are wearing pretty evenly, so on a compression test you're looking for consistency between the cylinders. Get yourself a compression tester (I have this one), unplug and pull all the ignition coils, pull all the spark plugs. This also gives you a chance to make sure they were installed well, make sure you put some dielectric grease inside each coil boot before reinstall if you didn't before.

    Ideally you will also unplug each fuel injector to save gas and prevent explosions, but as there's no spark with the coils unplugged it shouldn't actually matter. This is an extra safety measure.

    Then you handtighten your compression tester into cylinder 1. On a normal car, you would then go crank the key for a 5-count so the starter will turn the engine over and build pressure. Write the number down, repeat again on cylinder 1 and write that down, then cylinder 2x2, cylinder 3x2, cylinder 4x2.

    The cranking procedure is different on a Prius. You have to put the car in inspection mode (ICE always running) to do the test. Then you hold the start key for a 5-count to crank it.

    So with your compression gauge all set up, sit down in the driver's seat, the procedure is:
    1. Press start once, then twice, with foot off brake to enter ready mode
    2. Now press and hold brake with your LEFT foot
    3. Press gas twice
    4. Shift to neutral
    5. Press gas twice
    6. Put it back in park
    7. Press gas twice. Now you are in inspection mode and ready for the compression test.
    8. Now with foot still on brake, press & hold start button for 5 seconds. After about 1-2 seconds it will start cranking. After 5 seconds it will stop cranking and your dash will light up with error lights, but that's fine. Test is done!
    9. Record your compression, release pressure, repeat on same cylinder. Now do the same 2x test on all cylinders.
    10. Your two tests on each cylinder should be roughly the same. If you're getting different results between tests, repeat as many times as needed on each cylinder until you know you're getting it right.

      If you see something like 150-150-150-120, with lower compression on cylinder 4, that would definitely explain your symptoms. Let us know what you see. A head gasket and a head job a) might not even be indicated, and b) is NOT engine broke. Getting the head pulled, valves machined, head inspected, gasket replaced, is a huge job but it's a big step short of a shot engine. That might be like $1000-1500 at a cheapish independent shop, whereas an engine swap would be more labor and the price of a new used engine.
     
    JahT, subhash and bisco like this.
  12. JahT

    JahT Member

    Joined:
    Dec 10, 2007
    142
    71
    0
    My recent problem with my 2008 with 195k turned out to be 'bad injectors', misfire code on 1 and 3, rattle shake at idle, and it would seem to run fine at higher RPMs and idle fine most of the time. In the process I also changed plugs, coils, cleaned the MAF and throttle body. I never did the compression test or the combustion gases coolant test, but both of those are easier than changing the fuel injectors so to may want to try those tests first.
     
  13. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    How did you know it was the bad injectors? In my case the check engine light blinks which i think meant fuel getting dumped into catalytic converter. Did you also have blinking check engine light?
     
  14. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    6,580
    3,414
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    A blinking check engine light usually goes along with misfires. Reading the ECM codes will confirm whether this is the case. Maybe there will be other or different codes that can direct where your attention should be focused.
     
  15. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    I checked the coolant reservoir now the level is much lower than the min level. I am really stupid not to check it regularly. Because of the position of it i assumed it would be alright. I don't know when it went below the min level. Do you think it can cause permanent damage to the engine. Is the coolant leaking? Can i just add more coolant and check?
    What can i do now to fix the engine?
     
  16. BuyJapanese

    BuyJapanese Member

    Joined:
    Jun 12, 2019
    61
    28
    0
    Location:
    Wisconsin
    Vehicle:
    2005 Prius
    Model:
    II
    You should suspect a blown head gasket at this point. The Gen3 has an issue where the EGR valve gets plugged up, leads to overheating, leads to warped head, leads to coolant leaking into cylinders, leads to hydrolock and destroyed engine. There's no particular issue like this in Gen2. It is possible that low coolant caused overheating which caused a warped head/blown head gasket which caused low compression.

    Get yourself some Toyota coolant (Zerex is the off-brand you can get at Napa, OReilly, etc but I always order Toyota brand on ebay) and/or some distilled water, check your coolant daily. You can get a cheap tester to test for exhaust fumes in your coolant also if you want. Also, since Prii stupidly don't have a temperature gauge, it can be helpful to keep a scan tool that can read temp plugged in and showing temp while you're driving.

    Looking back at your first post, this started in the MIDDLE of a drive...that might be the drive where you lost all your coolant or your thermostat was stuck closed or something??? You may have been experiencing severing overheating and a warped head right during that drive.

    Anyway if I were you I would either a) take it to a shop or b) top off the coolant and do a SHORT drive with a temp scanner plugged in and see what happens
     
  17. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    @BuyJapanese thank you very much for the help. First i would try the option b and see if it improves. If not i will get it towed to a shop or see if i can change the head gasket by myself. Right now i use a bluetooth device with torque app as to read the codes. Do you think that can track the coolant temperature? I will also look it up. Do you have any recommendation for the scan tool?
    Also does the coolant color really matter? Right now i think the coolant is pink in my car. Should i buy the same color?
     
    #17 subhash, Mar 16, 2022
    Last edited: Mar 16, 2022
  18. BuyJapanese

    BuyJapanese Member

    Joined:
    Jun 12, 2019
    61
    28
    0
    Location:
    Wisconsin
    Vehicle:
    2005 Prius
    Model:
    II
  19. subhash

    subhash New Member

    Joined:
    Mar 7, 2022
    8
    2
    0
    Location:
    Gainesville
    Vehicle:
    2008 Prius
    Model:
    One
    Good that you mentioned it otherwise i would have just filled the reservoir.
    So first fill the radiator cap, next start the engine let the air out, stop the engine, let it cool then fill the reservoir?
    If not correct me. How long should i let the engine run?
    Also does the coolant color really matter? Right now i think the coolant is pink in my car. Should i buy the same color?
    the manual just says "toyota super long life coolant".
     
  20. BuyJapanese

    BuyJapanese Member

    Joined:
    Jun 12, 2019
    61
    28
    0
    Location:
    Wisconsin
    Vehicle:
    2005 Prius
    Model:
    II
    Pink/orange is probably OEM. I would stick with that. Get it from a local dealer if you're in a hurry. Yes, do what you described and run the car for maybe 10 minutes with the heat up all the way to reach operating temp (coolant at like 180F) so the thermostat opens and the coolant circulates through the heater core. Does the misfire go away when you rev up? If so I would top up the radiator (and reservoir to the full line) with the car off, then with the reservoir cap ON and the radiator cap OFF turn the car on in inspection mode and rev it up if needed to reduce the misfire. Keep your foot on the gas for a couple minutes. Then get out, top off the radiator, and back to the gas pedal if necessary to rev it up to keep it from misfiring as much as possible. Keep doing this for ~10 minutes, keeping radiator full.

    Eventually thermal expansion of the coolant will have it "boiling" out the radiator cap. At that point, shut the car off, get the radiator cap back on (wearing a glove, duh) and let it cool down. As the coolant cools and condenses the radiator will suck more in from the reservoir and stay full.

    Then start it up, go for a drive with your scanner plugged in, and see what happens.
     
    subhash likes this.
Loading...