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Does "throttle body cleaning" help milage?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by cosgrove, Aug 12, 2012.

  1. cosgrove

    cosgrove Junior Member

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    About 1yr ago while getting an oil change in our '10 Prius III Mod 5, a service rep came into the waiting room and announced a special on Prius "throttle body cleaning" for $100.00. This was supposed to improve milage, etc., but since our milage was just fine (51-52 mpg overall in summer) I figured it was a typical dealer scam and passed.

    About a month ago, no changes in car tires, etc., the milage suddenly dropped to 48-49 mpg. We have been having an unusually hot summer, but that is the only difference in driving conditions I can think of. We have about 70000 miles on the car, mostly highway driving on pavement.

    My questions: has anybody out there had this throttle body cleaning done and did it help the milage any? Also, has anybody had milage drop when temperatures rise from the 80's to the 90's? Thanks-
     
  2. fuzzy1

    fuzzy1 Senior Member

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    Higher temperatures often mean more AC use, which will reduce MPG.

    After hearing reports of catalytic converter failures shortly after throttle body cleanings, I'd exhaust the other possibilities for lower MPG before allowing such a cleaning on my car. And since every fuel injected nonhybrid in my household has driven far greater distances without ever needing such a cleaning, I'd also want a better explanation of why a Prius would need it.
     
  3. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    I recommend my version of throttle cleaning ($40-$60 for Prius) every 60K. Many dealerships, repair shops and quick lube places like to up sell lots of unnecessary procedures we call wallet flushes, as in your wallet. I doubt that $100 service is half as good or thorough as mine. If a throttle body gets dirty enough it will start to cause problems and by that time it will usually be a pain to clean. Cleaning it, as well as the MAF sensor, before they are troublesome and difficult to clean is best. Where my cleaning involves scrubbing, some places just spray some cleaner into the throttle body (not very effective), throw a can of cleaner in the gas tank and send you to the cashier.

    On the MPG, higher temperatures will defiantly effect MPG if the A/C is being used. If you were to keep the A/C on the same setting it will have to work harder to keep up.
     
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  4. phoenixgreg

    phoenixgreg Senior member

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    +1 to AVI's post. I used to clean my TB plate on my prior car and you'd be surprised how gunked up it can get even using the best fuels. Don't use sprays or tank additives...make sure your tech removes the plate cover, cleans the plate with proper solvents and then does the same with body itself. MAF = mass airflow sensor.
     
  5. edthefox5

    edthefox5 Senior Member

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    Not sure about the Gen3 but G2 gets very sooty. Most modern cars do. Soot turns to gunk and if really bad rusts the brass butterfly plate.
    Its very easy to clean the TB. My method does not put the Cats at risk and really you would have to spray a huge amount in the TB to effect the cats. Carb cleaner burns quite nicely.

    All you need is a can or 2 of carb cleaner. 2 old t shirts you rip into 2 inch wide long strips. Shove a strip down the throat of the TB with tail hanging out. Shove past butterfly while holding throttle open. Wear surgical gloves. Soak the strip with carb cleaner. Scrub the soaked strip against the wall and butterfly. I used a wooden drum stick to scrub low past the butterfly. Pull the strip out and it will be black with soot and it takes all the cleaner out with it leaving tb dry. Repeat.
    let it sit for 10 minutes before starting to make sure its dry. Then spray some lubricant on the throttle spring.
    Done.

    If your not sure it needs it or not just take air cleaner cover off and with a flashlight look down the throat of the TB.
    You can reach around the side of the TB and turn the throttle valve by hand and open butterfly and look all the way down. If you see soot or black spots on the brass butterfly it needs a cleaning.
     
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  6. ETC(SS)

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

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    +1 to the above posts, with some additions/caveats.
    Caveat: I've not done this on a Prius.
    Additional info (TIFWIW): If you go to the average Toyota dealer? You don't have to worry about your catalytic converter. They'll use the "spray and pray" method, and they'll just barely do that. I've heard from wrenches that just pour a can of "tb cleaner" in the gas tank, and then knock the customer on the head for 100 bones.....AFTER they've made sure that there are no rough idling conditions that are usually the first signs of a MAFS or a TB gunking.
    Sometimes? They'll get out a wand and try to spray some more aggressive cleaning agent into your car, and your cat doesn't necessarily like it, but unless you're having this procedure done bi-annually, or you're one of those people who are always pouring cans of miracle juice into your tank, then one dealer cleaning isn't going to hurt an otherwise healthy cat.
    The only trouble is......it's probably not going to help your TB all the way either.

    I recently cleaned the TB on our spare vehicle (06 Envoy @ 120k) which was stumbling a little @ idle. My flashlight said the TB was clean, and so I presumed that it was and proceeded to replace a few other things and clean the MAFS---I use fiber cleaner, but many other things will work if you don't feel like paying $9 for a can of MAFS cleaner @ AutoZone.
    I was to the point of investigating the injectors when I received, and heeded a little itch on my backside to further investigate the throttle body assembly.
    It was clean...on the FRONT side! When I removed it from the vehicle it was VERY dirty on the other side!!
    It took two cans of carb cleaner and some brush work to remove said deposits, but that did it.

    So....
    The takeaway is:
    1. If your vehicle is idling normally, you probably don't have an issue with the TB or the MAFS, but if you're at 50k+ miles, you may want to clean it, or have it cleaned. It's NOT hard to do yourself.
    Just don't expect miraculous fuel efficiency gains.
    2. If you cannot (or will not) do this yourself and you're thinking about letting the dealer do it? Go buy 100 lottery tickets. Your throttle body will get just as clean, and who knows???? You may not have to worry about it anymore.
    3. An independent repair person might be a better way to go with a proper TB cleaning, after you've explained what you want done (remove and clean.) OR you can use this as a little test. Remove the TB (or get a friend to do it) and scribe your initials into the black soot.
    Have the TB cleaned. Inspect it again. If they really remove the TB to clean it, then you know that you've found a wrench that you can believe in! :)

    Good Luck!
     
  7. Jason dinAlt

    Jason dinAlt Member

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    The Atkinson Cycle does allow some reverse flow in the intake system. This can lead to sooty deposits which are unlikely to cause any problems (it's a pretty good lubricant). The problem comes from mixing the soot with oil - it then forms what is technically known as gunk. :) There should not be any oil present. The presence of oil is a sign that there is something majorly wrong about to happen.
    Inspect the throttle body yourself. If the deposit is dry and sooty, ignore it (or clean it yourself if the cosmetics bother you.) If the deposit is oily and wet, clean it (again, something you can do yourself) and start saving your money for an engine rebuild.
     
  8. gliderman

    gliderman Active Member

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    Is there a diagram on how to remove the TB for cleaning? Thank you!
     
  9. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    This is similar to the way I do it. Another advantage is it removes any oil that has built up at the bottom of the intake manifold. I also clean the MAF while I'm in there. All this for way less than $100. Throwing in a bottle of techron concentrate as well will for sure seal the deal.
     
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  10. Former Member 68813

    Former Member 68813 Senior Member

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    I cleaned non electronic throttles before, but it is safe to move the plate manually in TBW systems?
     
  11. phoenixgreg

    phoenixgreg Senior member

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    Good question...I too have cleaned manual throttle bodies and you need to tip the plate almost 90 degrees (full open throttle) to do a decent cleaning of both the plate and the body. I think some blow-back is normal over 50K miles so don't panic if you see a bit of "gunk" on the edges and backside of the plate. Any engine will accelerate more smoothly after a TB cleaning. I doubt it will affect MPG, if at all.
     
  12. edthefox5

    edthefox5 Senior Member

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    Soot is a pretty good lubricant? Oil is usually present in the bottom of the Intake of an Atkinson. Get a flashlight and look. My 07 has had a puddle at the bottom of the intake since new.

    A sooty throttle body is not cosmetic.

    Not neccessary to remove TB to clean entire throat. Just open the butterfly by turning the spring. You can clearly see all the way down to the intake as mentioned in my last post.
     
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  13. edthefox5

    edthefox5 Senior Member

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    Sure is. Its connected to a motor and the motor doesn't mind rotating when the car is off.
     
  14. phoenixgreg

    phoenixgreg Senior member

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    Access throttle body 01.JPG Access throttle body 02.JPG Access throttle body 03.JPG Access throttle body 04.JPG Access throttle body 05.JPG
    Here are some diagrams from the manual (do this at your own risk). Once you get to the throttle body plate, edthefox5 says you can tip it open, inspect and or/clean.
     
  15. gliderman

    gliderman Active Member

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    Great pics! Thank you!
     
  16. Tbkilb01

    Tbkilb01 Active Member

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    Tooty frooty nice and sooty... 162000k... Techron additive? Seems todays 10% ethonal gas adds enough additive? I looked at MAF and looked awfull tiny to deal with. Seemed 1 small spray with cleaner would knock it off? I just left it alone. I needed a magnifying glass to see it! But throttle got my attention. Thanks for info-mation! image.jpg
     
    #16 Tbkilb01, Sep 11, 2016
    Last edited: Sep 11, 2016
  17. StarCaller

    StarCaller Senior Member

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    that's pretty much nothing for 162.000 miles/
    just cosmetic/
     
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  18. Toppcat

    Toppcat Member

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    Temperature, air density, and what in the air , fuel energy has a huge impact engine output ! Driving in death valley temperature at 120+ seen mpg and power drop up to 40℅. Throttle body cleaning is a rip off , mostly they just spray some carb cleaner and bam! Extra 100 bucks! Unless you have worn out engine with lots of blow by or problem with egr system!
     
  19. Tbkilb01

    Tbkilb01 Active Member

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    Crossing out maintenance list... Im thinking EGR system cleaning could be next... any tells?
     
  20. Raytheeagle

    Raytheeagle Senior Member

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    Rough engine transition is one. Lower gas mileage is another. I've done the front to back egr system as well as complete intake system cleaning.

    This is an older thread. What symptoms do you have or what are you experiencing?
     
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