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Need advice on doing engine cleaning

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by abubin, Jan 6, 2021.

  1. abubin

    abubin Member

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    I can see that lots of people tried the Seaform spray way to cleaning the engine through the air intake hose.

    I wanted to try using Liqui Moly intake valve cleaner instead of Seaform. This cleaner is in liquid form and need to use bottle spray to slowly spray into the throttlebody. This idea comes from a famous youtuber called Nates Interactive Auto.

    Anyway, last weekend I tried to do it but failed. I open up the air intake host joint after the MAP sensor, after the 90 degree bend. Then I activated Maintenance Mode and started the car. However, the engine died after a while. It is not getting enough air? Or maybe the MAP sensor is not accurate thus causing fuel/air mixture to be too low to sustain the engine running.

    I need big hole to cater for the spray bottle. Any idea how I can have the ICE engine idling while I spray the cleaner into throttle body?

    prius-airintake-throttle.jpg
     
  2. mjoo

    mjoo Senior Member

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    I see two ways of doing that:

    1. Open only the air box and spray before the MAF sensor.
    2. Tee into the PCV hose and, using a needle valve and 2 long hoses, dip the hose end into the cleaner and slowly add cleaner (crack the needle valve).
     
    #2 mjoo, Jan 6, 2021
    Last edited: Jan 6, 2021
  3. ChapmanF

    ChapmanF Senior Member

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    You don't mean the MAP sensor, you mean the MAF sensor. (You're in the Gen 3 forum, so your car has both. The MAF sensor is mounted up on the air box, and the MAP sensor is mounted down on the intake manifold, beside the throttle body.)

    I think I once succeeded in doing that sort of treatment (on a Gen 1) downstream of the MAF sensor, but I don't remember how I did it exactly. The ECM might say "hmm, bogus MAF reading" and fall back to open-loop defaults and that might be enough to keep lumping along, as long as you're not spraying the gunk in too fast.
     
  4. mjoo

    mjoo Senior Member

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    Yeah it's the MAF sensor. Sorry my brain copy-and-pasted
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Ok, apologies for being grumpy, but you’re saying:

    internal combustion engine engine

    Anyway, 2 cent opinion about your quest: don’t do it. If you want to clean something, remove intake manifold and clean completely (especially Exhaust Gas Recirculation passages), plus throttle body and MAP sensor. No need to disconnect coolant hoses for the throttle body removal. I can post torque value info in a bit.

    Consider Oil Catch Can install?
     
    #5 Mendel Leisk, Jan 6, 2021
    Last edited: Jan 6, 2021
    Paul E. Highway and Ed Beaty like this.
  6. abubin

    abubin Member

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    Done cleaning EGR, intake manifold, throttle body, MAF sensor and installed OCC too. Only part need to clean now are the pistons and cylinder heads which short of doing an top overhaul, I want to try something simple first.
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    I’m curious why the need: oil consumption, mpg dropping, start-up knock, something else?
     
  8. abubin

    abubin Member

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    Yes, there are oil consumption issue. But this is common in Prius. Cause cleaning the internals are good for engine maintenance?
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    I don’t think an intake spray cleaner will do much (if anything), besides creating a big cloud of smoke. Mr Lube is big on this service near us, I think the benefit is mostly psychological. I don’t think it can screw anything up, being downstream of the MAF sensor.
     
    mjoo likes this.