Cylinder 1misfire...fixed

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by steamroller, May 21, 2025 at 1:39 AM.

  1. steamroller

    steamroller Junior Member

    Joined:
    Jun 8, 2007
    7
    3
    0
    Hi Everybody...long time lurker...

    I have Four Gen 2 Priuses all 200k+ miles... used to have five...first one lasted 306k miles... bought it brand new 0 miles in 07

    I've gotten lots of information from this forum over the years so I thought I'd give something back...

    I had a check engine light with a code of cylinder 1 misfire ....couldn't get rid of it... change the plugs.... and the coils ...went through about four bottles of fuel injector cleaner .....nothing would get rid of it...

    and I couldn't get a smog check because in SoCal and the check engine light was still lit

    New fuel injectors are $100 a piece at O'Reilly and $200 a piece from the dealer...

    The O'Reilly's guy suggested... why don't you just clean them.. good idea!

    Took the car home... only took about 5 minutes to pull them out.. got to be really careful and have a vacuum cleaner with a small hose ready to suck out any crap dust debris before it drops into the cylinder

    They were REALLY dirty!

    Scraped them with some wooden popsicle sticks split in half... and blasted it with throttle body cleaner and shop rags....And they look good as new

    Installed them back in the car...turned it on and the check engine light went away all by itself.. drove the car 200+ miles and no problems.... feels like a RACINGPrius now!... checked it with OBD II...itll pass smog check no problem
     

    Attached Files:

    Danno5060 and Brian1954 like this.
  2. saneesh8

    saneesh8 Member

    Joined:
    Jul 5, 2024
    129
    26
    0
    Location:
    Allen, TX
    Vehicle:
    2009 Prius
    Model:
    One
    Clean the others also. I cleaned them on my old bmw while back. Fill the port with brake fluid, apply 12V power and blow threw it with compressed air. Immediate difference.

    Did you replaced the O-Rings?

    You could get it professionally cleaned also.
     
    steamroller likes this.
  3. steamroller

    steamroller Junior Member

    Joined:
    Jun 8, 2007
    7
    3
    0
    Yup I cleaned all 4 injectors...

    Bought 2 sets of replacement Orings because thats all they had...but the stock ones looked good so decided to leave them in...hopefully not leaking but will check later

    Is THAT how they work!?...hit it with 12 volts and blast it with compressed air...See!...thanks again!...I was almost certain I had jammed some gunk into the little holes and wasn't sure how to clear them out...ok will try that too!...awesome
     
  4. pasadena_commut

    pasadena_commut Senior Member

    Joined:
    May 2, 2019
    2,168
    642
    0
    Location:
    Southern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    Out of curiosity, has the OP been using something other than "top tier" gas?

    Interesting that 4 bottles of injector cleaner didn't help. Techron or something else?

    Did I read this right, only the outside was cleaned? As in the outlet holes were clogged right at the surface but (apparently) not the innards?
     
    Danno5060 likes this.
  5. steamroller

    steamroller Junior Member

    Joined:
    Jun 8, 2007
    7
    3
    0
    Yes ran through 4 smaller bottles of Lucas fuel.injector cleaner...thats.2 bottles each in 2 tanks of gas...92 octane from chevron and shell...

    Only the outside was cleaned...sprayed with throttle body cleaner and scraped with wooden popsicle.sticks...im almost certain i jammed some gunk into the little holes...but now that I know how to clean the inside I'm going to try the compressed air method next...
     
  6. steamroller

    steamroller Junior Member

    Joined:
    Jun 8, 2007
    7
    3
    0
    Always use 92 octane from whatever gas station I go to
     
  7. Hayslayer

    Hayslayer Member

    Joined:
    Nov 6, 2024
    165
    89
    0
    Location:
    USA
    Vehicle:
    2009 Prius
    Model:
    Touring
    You are wasting money. Octane rating is merely a measurement of a gasoline's ability to resist detonation/early ignition, not a measurement of a fuels ability to keep the fuel system clean or a measurement of how "good" a fuel is. This resistance to detonation is achieved by additives and some say it's designed to burn more slowly. I think that's always going to be debated. A Gen 2 engine is designed to run perfectly fine using 87 octane fuel and will likely run better on 87 than 92. You'd likely be much better off using an 87 octane fuel from a top tier rated supplier. Even Costco is top tier.

    Is The Top Tier Gas Myth A Scam Or Is It Worth The Extra Cost?

    Top Tier gas isn’t just a marketing ploy or a myth – it’s backed by scientific research proving that it helps keep your engine cleaner and running more efficiently. Unlike regular gasoline, Top Tier gas contains a higher concentration of detergent additives that actively reduce carbon buildup inside your engine, improving fuel economy and extending engine life.
     
  8. ColoradoCrow

    ColoradoCrow Senior Member

    Joined:
    Sep 2, 2019
    1,073
    441
    1
    Location:
    Leawood, KS
    Vehicle:
    2008 Prius
    Model:
    I
    Whats the best way to add 12 volts to the injector when it is out of the car? I have a 12V sleeve power supply.... and a compressor... clean with what? then blow out?
     
  9. Hayslayer

    Hayslayer Member

    Joined:
    Nov 6, 2024
    165
    89
    0
    Location:
    USA
    Vehicle:
    2009 Prius
    Model:
    Touring
    Keep in mind an injector is not 100% duty cycle. I think injectors usually have 12v applied at all times and the ecu just connects the ground when it needs to be activated. I also don't know if the ecu acts as a current limiting device. I've always heard being energized "long term" may damage the coils. I've never had the need to find out, so I can't speak from experience. Regardless, good luck and let us know how it goes.
     
  10. saneesh8

    saneesh8 Member

    Joined:
    Jul 5, 2024
    129
    26
    0
    Location:
    Allen, TX
    Vehicle:
    2009 Prius
    Model:
    One
    What i did is,
    1. Add brake cleaner to the port.
    2. Have the 12V connection ready. I used a 12V dc adapter. Less amps than a car battery.
    3. Blow through it and on/off of 12V. Kind of simulate the pulse from the ECU.

    I did this like 20k miles and few years back on the bmw. Never had issues. What i know is, ECU sends pulses to the injector to turn it on/off matching with timing and all.

    Safe way is to send it for professional cleaning. They do much more.
     
    ColoradoCrow likes this.
  11. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    26,072
    17,047
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Rich Jensen at Cruzin Performance, who used to do the injector restorations when this forum had an injector exchange going for a while, used to suggest using an ordinary 9V battery for testing (short of having an injector test rig that makes proper 12V pulses). 9V was enough to test the injector, and less likely to damage the coil in a manual, non-pulsed test.
     
  12. pasadena_commut

    pasadena_commut Senior Member

    Joined:
    May 2, 2019
    2,168
    642
    0
    Location:
    Southern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    Sam's Club isn't, unless they have changed recently.