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Fuel System Cleaner Q


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Greetings.

 

To make this story short:

 

Went to service a different vehicle (2011 Mazda 3). The dealer stated I might need a "Fuel injector and throttle body service" that comes up to $245, due to some carbon build up.

 

I really doubt I will do that...

 

Now, why I post here? Well, my Legacy 2013 - no issues or nothing, but (here goes the Q), is it recommended to use some kind of fuel system cleaner (like the chevron techron or something)? If so, what is recommended (brand and such)?

 

I've had my Legacy for about 2.5 years now (purchased it at ~34K odometer), and never used any additives or done anything to it other that the recommended service (oil/filter). I do my own cabin and engine air filter changes. (I'd do my oil changes, but living in NYC there is no place to do it on your own).

 

I'm at ~49K miles odometer - drive less than 10K/yr city, with the usual road trip of 300/m round trip.

 

PS - my wife drives this car, and every now and then she's the one filling it up for gas, so god only knows what she uses, likely the cheapest, might be non-brand...

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Fuel injector cleaner can be used now and then to clean up the injectors but then it's a good idea to check the injectors too when the car has been driven some distance, but it should be done by someone specialized on injectors. If I were to keep the car I would probably have that done for the 50k mile mark. The reason is that if injectors starts to go bad it can later result in valves and cat also suffering and then the price of the injector service may be a lot cheaper.

 

As for cleaning the throttle body - that's usually not too complicated for anyone used to work on cars. Also clean the MAF when you are at it.

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I've been using Chevron with Techron for probably 15-20 years now and will continue to do so every 10-15,000 miles or so.

I had a 91 Honda Prelude that for over 17 years and 200,000 miles and NEVER had a check engine light or any fuel issues. period. Just normal oil changes, spark plugs, wires, cap & rotor every few years, 1-2 valve adjustments for good measure, etc.

 

So, yes, it's cheap insurance and peace of mind I suppose.

 

Now, for actual heavy carbon buildup, you may want to get aggressive with Seafoam. You can google/youtube best methods for that.

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thank you all for the replies.

 

I'm looking into Lucas / Techron / Liquimoly / Royal Purple fuel cleaners to see which one convinces me the most. I reckon they all work, as they all have positive reviews and are recomended...

 

Now ehsnils, can you suggest some documentation/tutorial/video as to DIY cleaning the throttle body - I've familiarized myself with the MAF and I'm very likely capable to do it myself (as I do change the air filters myself), but I've never dwelled that deep into things...

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I've always used BG 44K. Every 15K miles or so. A few years back I wanted to save some $ and use the Subaru brand fuel additive but my dealer parts department said it's crap, stick with the BG, lol. (Since the dealer said it, it has to be true!)
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This is just a bit of info for general knowledge. The Mazda induction service made me think of it. All the newer cars with direct injection suffer badly from carbon on the valves. I have seen cars with as few as 50k on them with misfire issues due to carbon on the valves. If any of you or your spouses own one of these cars then you need to do a full induction service every 15-20k miles. It is pricey, but seems to keep the carbon at bay. I have seen cars that have to have a full valve job just because of the carbon buildup. Oddly enough, the only new car with DI that does not suffer from this is the new Subaru DI engines. Not sure if it was intentional or not, but Subaru added a cold start injector. This initial spray of fuel seems to keep carbon from forming. Again this is just an educational tidbit. Not directly related to this thread.
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Its only not a problem on the BRZ/FRS/FT86 FA which has a dual PI and DI setup.

The FA16DIT and FA20DIT still suffer from DI carbon buildup on the valves and valve channels thats so common with most DI engines.

 

Some WRX, FXT and Levorg owners make use of BMW or custom walnut blasting machines, others add water/meth port injectors and couple them with AOS or catch cans, others still do nothing and start to see buildup issues as early as 10-20K miles!

 

CRC supposedly has a new cleaning tech/kit specifically designed for DI engine woes, but mechanical (walnut, etc) removal seems to work best thus far.

 

For our older PI engines, most of the cleaners or fuel additives mentioned above should work well.

 

Personally, I'm biased toward Lukasoil and Berryman products.

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Not sure what your US dealers do, but here in the land of Oz, the 6monthly service usually includes a Sea-foam like top engine clean SA459 (into the intake), fuel system cleaner into the tank and another bottle of fuel system cleaner to add yourself 3 months later to maintain the combustion chamber carbon free. Never having seen it though I wouldn't know!

 

The Boxer engines are sensitive to combustion chamber deposits, leading to misfire and pre-ignition so I have read. Not that our engines are DI, but still that seems to be a issue for some of them.

 

One thing I do notice that immediately after a good highway run of at least 30 mins, the engine seems to run a lot smoother and throttle pick up is quite sharp, as if any build up of carbon has been burnt out with the continual lean running at light load.

 

Prevention of carbon build up by using high octane high detergent fuels and putting an AOS on the car will stop most of it unless you only ever do short trips in a cold climate.

 

Can't believe that walnut blasting is a thing, but obviously works.

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Scotty Kilmer says to put a catch can on the DI engine to greatly reduce the amount of oil vapor going into the intake on a DI engine. This will greatly reduce the amount of buildup

 

To keep carbon off of the valves you will have to regularly spray fuel injection cleaner down the intake manifold.

 

here is a video that explains it in detail

 

for regular SMPFI engines regular use of a fuel injection cleaner will suffice...

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After seeing my plugs, I took Perscitus' suggestion for fuel cleaner. Half a bottle of Berryman B12 for half a tank before a long trip then the other half in a 1/4 tank. Also ran some Lucas not too long ago. That and new plugs definitely helped a ton. I'm curious about the Amsoil P.I. and if it's any good.
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Now ehsnils, can you suggest some documentation/tutorial/video as to DIY cleaning the throttle body - I've familiarized myself with the MAF and I'm very likely capable to do it myself (as I do change the air filters myself), but I've never dwelled that deep into things...

 

Here's one video at least:

[ame=http://www.youtube.com/watch?v=7DCTDMDo3JU]How to Clean a Throttle Body and Idle Air Control ( IAC ) Valve - Quick and Easy - YouTube[/ame]

 

And when you have done everything, disconnect battery and push brake pedal for some 20 seconds, then reconnect battery to clear the ECU of old history with the dirty stuff. Notice that it will have to re-learn so the idle would be crappy initially but just take out the car for a nice fine slow drive where it can warm up and re-learn. Mixed type of traffic is best.

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I have cleaned various throttle bodies at 40-60K miles and they have been pretty clean at that mileage. The only ones I have seen as dirty as the video is the vehicle with 150k miles. I will probably clean mine when I do the timing belt at 105k.

 

I have never used any injector cleaners additives, but its is probably good preventative maintenance. I have had a couple sets of stock injectors clean with 45-100k mileage and they all flow better after cleaning. The ECM has the ability to compensate for evenly dirty injectors but not in the instance of one injector being clogged much more than the other.

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