EGR/Intake Manifold Cleaning...Then It Happened...

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by FlyboyTR, Sep 10, 2019.

  1. FlyboyTR

    FlyboyTR Member

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    A few weeks ago I did the full EGR valve, cooler and intake manifold cleaning. The cooler was about 70% occluded. I did a gravity water flow test to determine this between dirty and clean. First I used the pressure washer which did great at blowing things out. The next day I sprayed straight Purple Power cleaner inside the cooler and suddenly thick dark tar like substance started running out. Purple Power did an AMAZING job of removing all the buildup on the three components. Super pleased. While I was cleaning these parts my helper asked if I wanted him to clean the intake ports on the engine (head). Sure.... This is where things may have went downhill...

    I instructed him to push blue paper towels down into the ports to prevent liquid and stuff from falling/running towards the valve seats, etc. I also provided him with two cleaners, one being the Purple Power. He was working like a mad-man and when he stepped away to get more towels I took a look and was very pleased with the progress. Until... I happen to step over while he was cleaning the last one. He had a small stainless steel brush and was using it and the cleaners to remove the carbon, suet residue. Still not a bad thing as he was very careful with keeping things clean. However, It was then that I noticed that he was also scrubbing the TOP of the intake port, including the fuel injectors which sits right there! ............sigh.......

    I stopped him and he confirmed that he had cleaned the other three the same way. I packed fresh blue towels into the intake and sprayed the tips of the injector (best I could) with carb cleaner. Everything was reassembled with new gaskets and the engine started right up and was a little rough for about 5 seconds, then smoothed out. Actually idled much better than before the cleaning. An Oil Catch Can was also installed.

    I noted over a couple of weeks while driving around town my MPG's seemed a bit low. This past weekend we did a 600 mile trip. Typical load and speeds. I normally average out between 40 & 42 MPG For the first hundred miles I got 32 mpg per the computer. I stopped and bought a bottle of Techron Fuel Injector cleaner, dumped it in and topped of the gas. Over the remainder of that tank the MPG's got close to 35. When I refilled I added a bottle of Techron Fuel Cleaner. The last 220 miles of the trip I averaged 36 MPG.

    So.....While I can't see a clean EGR/Manifold system causing this, I am left to believe that the injector tips (that were scrubbed with a stainless brush) may have been damaged and has caused this sudden drop in MPG performance. The engine seems to actually run stronger but the MPG's are WAY off!

    I would welcome your input and suggestions regarding my situation. Thanks!
     
    #1 FlyboyTR, Sep 10, 2019
  2. tankyuong

    tankyuong Senior Member

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    Car would throw a code if injectors were damaged, I think you’re fine
     
    #2 tankyuong, Sep 10, 2019
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  3. ChapmanF

    ChapmanF Senior Member

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    The car doesn't have any kind of sensor that would tell it directly about the condition of the injectors. You could get a system-lean or system-rich code if they were far enough out of spec to trigger one. Not that far out of spec, you might still get some information by reading out the long-term fuel trim.

    The real tests of an injector are to take it out and verify that it flows the right amount of fuel in the right stopwatch time, and that the fuel spray pattern is a nice well-atomized cone. Problems there might not be reported by any code, but could still affect the engine performance. I could see grunging the nozzle with a wire brush possibly leading to a funky spray pattern.
     
    #3 ChapmanF, Sep 10, 2019
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  4. FlyboyTR

    FlyboyTR Member

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    Chapman,
    Thanks for the info...appreciated. I really want to pull the injectors and check them before leaving on my 4 week, 7K mile trip...but my departure time is too close. Thankfully no codes and it is running good/better than before the EGR cleaning. I just hope the MPG's continue to improve. I will certainly report on this after my trip. Thanks again! :)
     
    #4 FlyboyTR, Sep 10, 2019
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  5. ASRDogman

    ASRDogman Senior Member

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    A wire brush to clean the injectors? NOT a very good idea!
    There are several methods to clean them with carb cleaner.
    The tips could have been damaged and are not spraying a mist.
     
    #5 ASRDogman, Sep 10, 2019
    Last edited: Sep 11, 2019
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  6. Rebound

    Rebound Senior Member

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    The car’s computer is not a good indicator of MPG. Here’s how you should do it:

    1) Fill the tank until click-off. No further
    2) Reset trip ODO
    3) Drive until empty. Or half full. Whatever.
    4) Fill tank until click-off. Ideally, same pump as before.

    Now you have miles driven and gallons consumed.

    Miles / Gallons = MPG

    300 miles / 7.42 Gallons = 40.43 MPG. Easy!
     
    #6 Rebound, Sep 11, 2019
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  7. frodoz737

    frodoz737 Top Wrench

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    Stainless brush scrubbing injectors means you need new injectors. While it may run better due to the maint. performed, the spray pattern will never be right and result a less efficient burn...more gas for same power. While I make this statement sight unseen, your initial results would indicate the damage done. Injectors are precision parts.
     
    #7 frodoz737, Sep 11, 2019
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  8. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    +1
    If the car is running strong and not spitting codes I'd wait to see what your tank averages are before trying to solve a problem that may not yet exist. @frodoz737 could very well be right (he fixes planes, I fix phones) but I would want some hard data before ordering the new injectors.

    Good Luck!

    Give us a SITREP when this sorts itself out.
     
    #8 ETC(SS), Sep 11, 2019
  9. FlyboyTR

    FlyboyTR Member

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    Thanks for the info. I really do feel like some damage has been done... I have to give my friend kudos for doing such an amazing job of cleaning the intake ports...and at the same time wish I had been watching closer! While I use the onboard computer for quick MPG's I do track every tank of fuel, miles and MPGs figured by math...not computer! :)

    I really hate that I don't have time to pull the injectors before leaving on our trip next Wednesday...the clock is ticking! I will be watching everything closely.

    LOL...glad to hear that @frodoz737 fixes planes...I do the same...well...I fix my homebuilts! ...and I do need a phone repaired! ...can't touch that! LOL

    Thanks again for the support and info...sincerely appreciated!
     
    #9 FlyboyTR, Sep 11, 2019
  10. Daniel Richard

    Daniel Richard Member

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    My mpgs dropped after I cleaned my EGR system as well. They did come back after about 500 miles. I think the computer has to adjust to the EGR system functioning properly again.
     
    #10 Daniel Richard, Sep 12, 2019
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  11. johnHRP

    johnHRP Active Member

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    I would check the injectors by pulling it out. If you can see obvious damage, than you replace it if not, I would wait for 2000 miles and see if the whole ECU complete the Re-Learn cycle of the fuel air and exhauts EGR air ratio in close loop. If you gave OBD2 scanner with graphic monitoring of O2 reading, it will tell you if you have rich or lean mixture. If it is rich, your sparkplugs will be darker and more shoot but you feel the car has more power. If it is lean, the ceramic is white clean and brownish color on the electrode. As you can see in my profile picture, That's normal sparkplugs color on the left after 60k miles.
     
    #11 johnHRP, Jun 10, 2020
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