What's a throttle body.?

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Burning Petard
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What's a throttle body.?

Post by Burning Petard »

I have a Toyota Corolla 2018 bought new in August of 2018. It was assembled in Canada on Jan 4 2018. It sat on a dealers lot in New Jersey until the local Toyota dealer in New Castle county, Delaware took it off their hands in July. I have no idea why they could not sell it in NJ. I have now put 55K on the odometer with no problems. I did put a new set of Michelins on it at about 50K. The factory recommends an oil change annually. I have been doing it my self at about half that interval. The other half at the dealer. The last time I did it disposal of the used oil in an environmentally proper way was a real hassle. I think never again. So after an oil change and tire rotation at the dealer this week, they presented me with a recommendation for lots more service -- nothing actually required, but it would keep me going with such a nice, trouble free ride.

Among other things, a throttle body cleaning for about $150 and fuel injector cleaning for another $175. "We recommend this every 30k miles to get best fuel efficiency". Now the only engine work I have done on a car with no carb was a spark plug change on a Ford Focus. I was thinking (perhaps erroneously) that a throttle body was an engineer's compromise between a carb and real fuel injection. If you have one, you don't have the other?

Does this nice little Japanese people mover, made in Canada, really have both? And if I use 'top tier' gas all the time and occasionally throw in a can of injector cleaner into the fuel tank, do I actually need dealer cleaning at 60K and more than $300?

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datsunaholic
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Re: What's a throttle body.?

Post by datsunaholic »

Yes, it has both.

The throttle body controls the amount of air going into the engine. The injectors control the amount of fuel. Your engine is port injected so the 2 are separate. Throttle Body Injection was the one that was basically a carb replacement.

Generally they don't need cleaning, but the throttle body can get gunked up since no fuel goes through it to help clean it. Some cars route the pcv through the throttle body and those get dirty in a hurry, and I've heard throttle body fouling is common in some Chrysler products.
Death is Nature's way of telling you to slow down.

Burning Petard
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Re: What's a throttle body.?

Post by Burning Petard »

I checked it out on you tube and the throttle body looks pretty simple to clean. The big thing is to remember just how the box air box hooks up so some other hoses can go in the right place. The electric control means the cleaning need to be sort of conservative -- DON"T spray cleaner on everything because you can mess up the electronics. Just put the cleaner on a clean cloth or paper towel and wipe it gently And use the right spray product, not just a can of gunk or WD40. A less than 5 minute job. The injectors looked to be a job that is worth what the dealer is charging.

Perhaps the price for the throttle body is to cover the risk of somebody getting in a hurry or sloppy and it takes a couple of hours to re-program the sensor and control. So far I have no symptoms of a problem. Acceleration and fuel milage is essentially that same as when I had just 10k on the clock.

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BoSoxGal
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Re: What's a throttle body.?

Post by BoSoxGal »

My 1999 Toyota RAV4 is still going strong at 210k miles and beyond regular oil changes did not get all that kind of stuff. I actually had a mechanic who told me it wasn’t really necessary. Was he wrong? I always did wonder which recommended stuff was really necessary v not - clearly a bunch of it is not, because my Reva is still reliably kicking after 23 years without a throttle body cleaning. I may have put one or two of those fuel injector additives to the gas tank over the years but not often at all wouldn’t need all my fingers to count them.
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Joe Guy
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Re: What's a throttle body.?

Post by Joe Guy »

I've learned that it's best to use the maintenance schedule that came with your car (if you have the schedule). Dealers and some mechanics will recommend unnecessary and sometimes costly services that you may not really need.

Burning Petard
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Re: What's a throttle body.?

Post by Burning Petard »

While I was there on you tube I looked at fuel filter change. On older Toyotas like that RAV4, it is messy and easy to get a face full of gasoline. On my car it is easy to get at the filter. One could do it without even getting your hands dirty. I really like it. Pull out the back seat and there is an access plate right there on top. A big unit, just pull right out. Take it to the bench, Remove a bunch of hoses, wires, fiddly bits, lots of little plastic clamps to open without breaking. And remember where it all goes. Take things out and wipe some with clean oil, blow off other stuff with air hose. Open replacement part kit and check carefully to be sure it is the right kit and put it all back together. And no parts left over. (that is always the hardest part for me)

I think I would rather deal with the gas in my face and leave the newer model fuel filter systems to the dealer. I am beginning to actually believe one could perform a DYI appendectomy with guidance from you tube

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MGMcAnick
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Re: What's a throttle body.?

Post by MGMcAnick »

They make spray cleaners for the throttle body that will clean the throttle butterfly area in the throttle body. I've only needed to clean a couple in my career. They were sticking in the closed position. When the butterfly let go, the car would lurch forward. You don't want to get that cleaner on the Mass Air Flow (MAF) sensor. That requires a special cleaner.
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Burning Petard
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Re: What's a throttle body.?

Post by Burning Petard »

Yep, MAF sensor was on their list too. I don't remember whether it was clean or replace, Is the MAF the new version of O2 sensor? That one seemed to go bad frequently on Fords in earlier decades. At least it sure liked to come up on the engine code reader.

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datsunaholic
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Re: What's a throttle body.?

Post by datsunaholic »

No, the MAF sensor and O2 sensor do different things. Your car will have both, as well as a host of other sensors (knock sensors, cam position sensors, crank position sensors, etc), plus variable valve timing, which is why cars nowadays can get 30+ MPG with engines capable of 200HP, whereas in the 70s you were lucky to get double-digit MPGs with 150 HP.

The MAF is what tells the ECU (Engine Control Unit) how much air is flowing in order to indicate how much fuel to deliver via the injectors. Gasoline engines have a very narrow range for the air/fuel mixture so the computer needs to know how much air is flowing (throttle position isn't good enough because more air flows at say 3500 RPMs vs 800 rpms even at the same throttle position). The O2 sensor is there to detect how much oxygen is exiting via the tailpipe... in most vehicles it's to fine tune the fuel amount and engine timing for the best efficiency, and also to monitor emissions (modern cars have o2 sensors before and after the catalytic converter) and tune for that as well.

Since O2 sensors live in the exhaust system, they're subject to extreme heat ranges which is why badly designed ones failed quickly. They still have a limited lifespan but we are talking 10 years or more now.
Death is Nature's way of telling you to slow down.

Jarlaxle
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Re: What's a throttle body.?

Post by Jarlaxle »

If you need an O2 sensor, I recall that all Toyotas have at least a 10/100K emission warranty, and maybe longer.

Surprisingly, some cars still do not use a MAF sensor. (My Challenger was speed-density.)

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