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First throttle body cleaning on new-to-me 2008

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by George W, Aug 24, 2018.

  1. George W

    George W Active Member

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    I'm into my fourth month of ownership on a 2008 Touring Prius. Mileage is 127,000. Have been working my way down the tune-up checklist, because gas mileage is low, about 36 mpg.

    So far I've replaced tires, battery, air filter, cabin filter, and cleaned MAS. Today I took on the throttle body.

    I took several pictures, except for the 'before' past the valve.

    [​IMG]

    After spray and brushing, there was TBCleaner at the bottom of the assembly. I went after this with paper towels.

    [​IMG]

    When the paper towels came back mostly white, I couldn't see any more to soak up.

    [​IMG]

    I'm hoping this will contribute toward improved fuel economy. Next tune-up item will be spark plugs.
     

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  2. audiodave

    audiodave Active Member

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  3. George W

    George W Active Member

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    The tires were purchased from a national tire chain, so I'm hopeful they align, after replacing all 4. The car drives straight.
     
  4. audiodave

    audiodave Active Member

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    It's a extra charge for alignment. Usually 80 bucks. Mine with badly worn suspension parts killing my tires because of alignment issues still drove straight. Milage went up to 46-47 after I replaced lower control arm, struts and alignment.

    Posted via the PriusChat mobile app.
     
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  5. audiodave

    audiodave Active Member

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    You also have a 10 year old battery and living in a warm climate. Assuming using the AC a lot?

    Posted via the PriusChat mobile app.
     
  6. George W

    George W Active Member

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    The HV battery was supposedly re-conditioned as a part of my purchase. It occasionally gets a single green bar, even in this hot summer
     
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  7. bisco

    bisco cookie crumbler

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    there's your problem. what tire model?
     
  8. audiodave

    audiodave Active Member

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  9. edthefox5

    edthefox5 Senior Member

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    You don’t use paper towels to clean a throttle if a big piece fell off you would not be able to get it. Plus they don’t clean well.

    You cut old t shirts or cloth up into 2 inch strips Hold the throttle blade open and shove one down the bore. Soak it in carb cleaner and then with it now in the bore and wet use it to scrub the bore. Then pull out and discard.
    Repeat.

    You cannot clean a tb very well with paper towels. Must use cloth then when you pull the cloth out no carb cleaner gets into the intake.

    Also You Did not pull off the 2 pcv hoses and flush out the inlets. These tb inlets are clogged with gunk.

    Then when done spray lubricant on the blade return spring. And make sure the 10mm bolt hose clamp under th air cleaner box is tight or air will sneak by the maf.

    You need to replace the plugs. You will probably find one spark plug well has oil in it. That’s a leaky valve cover gasket. Very common.

    My car has the same mileage. When I replaced my plugs I found the 2 PCV hoses were shot too. the ends were all dried up and cracked. They have tight special right angles was not able to find auto parts store hoses to fit. Had to buy oem new ones online. They were not bad like $15 each,

    So get ready to change the plugs look in the plug wells and since that area is all apart the pcv hoses are right there to pull off and replace.

    Also since you live in a god awful hot place Like me 11 years ago when I bought mine I bypassed the throttle body coolant loop. They run rad radiator coolant through the tb for winter deicing. My car has never seen a winter. Car runs much better with a cooler tb and taking 200 degree heat off the tb increases the life of the tb motor.
    This is an old throttle body mod done on many cars that live in the south.
    I just use a pex 3/8 barrel I bought at Lowe’s and 2 small hose clamps to connect the hoses back together. That was 11 years ago never an issue and car runs great.
     
    #9 edthefox5, Aug 25, 2018
    Last edited: Aug 25, 2018
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  10. audiodave

    audiodave Active Member

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    Any change in milage after by passing the coolant to the throttle body?

    Posted via the PriusChat mobile app.
     
  11. edthefox5

    edthefox5 Senior Member

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  12. audiodave

    audiodave Active Member

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    Can you post a pic? Just a link to the two lines?

    Posted via the PriusChat mobile app.
     
  13. George W

    George W Active Member

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    They are the House brand carried by the national chain, supposed to be the same size as OEM. I say this because when I took the car to them I specifically asked for the correct tires for this make and model. I thought that's what I had received. Yet when I look at the receipt, the fine print says that I have chosen a tire that is different from the OEM for my vehicle. I I have to go back and ask Wth. if they didn't have the OEM tire they should have informed me prior to taking my money.
     
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  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Nice work on the TB cleaning. I would not expect the TB cleaning would help fuel economy. However it may avoid an engine no-start situation.

    Replacing the iridium spark plugs may help fuel economy. Keep the tires inflated at 42/40 psi to encourage even tire tread wear and optimize mpg.

    The default tire size is 185/65R15. If your Touring model has 17" wheels then the tire size is 215/45R17. See what the tire size actually is before you get upset about the fine print.

    Because the Touring tire size is wider than the Base tire size, that will not help fuel economy. However you hopefully will experience improved handling.
     
  15. George W

    George W Active Member

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    This Touring has 195/55R16 . The maximum rated psi is 51 (House brand tire), but the handbook says 35 is recommended. I've seen in other threads where members have also increased to 40+ psi. When my tires are just sitting on hot pavement, they get up to near 40 on their own.
     
  16. Mendel Leisk

    Mendel Leisk Senior Member

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    I'd speculate you pull off the two highlighted hoses and splice them together. Looks like a couple of 90 degree elbows and short section of hose would do it. What's the ID, 3/8"?

    upload_2018-8-26_9-30-46.png

    Maybe plug the pipes on the throttle body too?
     
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  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    OK, then you have the right tire size for 16” wheels.
     
  18. Naurill

    Naurill Junior Member

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    Acetone is less expensive than carb cleaner to clean the throttle body (check the hazard data sheets to make your own decision).
     
  19. edthefox5

    edthefox5 Senior Member

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    Thanks for the diagram Mendel. Once you pull them off you can cut off the 90 degree ends and under the tb they will then meet each other just connect them with a barrel I used a Pex plumbing barrel I think it was 3/8. Can’t remember it’s very small ID. Bought at Lowes or Home Depot. You lose a tiny bit of coolant when you pull the hoses. Drive it a little let it cool down and then open the rad cap not the overflow and check level.
    Maybe half a cup. No air lock induced though.

    Pex barrel and 2 small hose clamps. That was 11 years ago still going strong. I left the ports on the tb open never bothered covering them. Nothing to seal really. Even on the coldest day of any winter we have had never a problem. But I would be hesitant to do this in any northern state.

    The tb goes from 200+ degree heat to once coolant removed to really very cool much less than the outside temp as all the air going through there is at a pretty good velocity and that has big cooling effect. It will greatly extend the life of the throttle motor and improve combustion.

    Car runs great.
     
    #19 edthefox5, Aug 28, 2018
    Last edited: Aug 28, 2018
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  20. edthefox5

    edthefox5 Senior Member

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    I agree but they do not make a spray acetone. You must use a spray to unclog the pcv ports. They are pretty gunked up. Actually one is gunked up the other is always clean.

    Carb cleaner at Walmart is pretty cheap. Buy 2 cans. Do a thorough job and it will last years if you run synthetic oil. Dino oil has much worse sludge and fumes that cause more sludge in the pcv system.

    My car has always run synthetic and sludge was not bad. The pcv valve at 130000 miles was in good shape
    Could hear it rattle when shook very minor sludge. The sludg collects at the tb inlet.
    Replaced it anyway since I was in there.
     
    #20 edthefox5, Aug 28, 2018
    Last edited: Aug 28, 2018
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