Intake Valve Cleaning---GDI Engines

[graygun]

Are any of the liquid/spray cleaners effective at this? I used the Sea Foam with the long,curved straw on my 20126 Civic 2L (naturally aspirated) engine about two months ago but don't know if it did any good. I just saw a video where a guy used the CRC equivalent and his pictures showed almost no cleaning results.

Are there any non-mechanical cleaning methods that work well ?

 

[graygun]

Engine has 103K and runs well but mpg is down to 28 from about 33 or so.

 

[Dave P.]

No personal success story but know people who think Techron fuel additive may actually do something if added to a few tanks of
fuel

 

[MHtractorguy]

Mr.Gasket Cataclean will clean everything that the fuel touches. It even cleans the catalytic converter and the inside of the muffler.

In order to clean GDI valves, nothing you can spray in the intake will work. Either add something to the fuel tank, or disassemble the engine.

30+year ASE Master Tech here

 

[RC44Mag]

My 135i N54 has direct injection and popular on the boards is walnut blasting. I had It done on mine about 4 years ago. Made a world of difference. Amazing how much gunk it removed and improved performance and mileage. It’s not cheap but it sure does work.

 

[GasGuzzler]

Why wouldn't something delivered through the intake help clean the intake valves? It would. It would not clean the injectors but that's not what the OP asked.

I would look elsewhere for your MPG. Unless that engine is a known carbon trap (like a GM 3.6), it's not the cause of your issue.

ASE Master
GM World Class
30 years experience

 

[Mobuck]

Marvel Mystery Oil is what I use. I try to use it once every 5-6 tanks of gas. Sometimes when I'm running hard, I don't meet this schedule and will see a slight MPG loss but another treatment brings the MPG back to 'normal'.
This is fairly easy to see when driving same roads to same areas time after time. I just got back from a longer trip that involved a wide variety of driving conditions and roads. 17.5 MPG. May not seem like very good but this is a 20 year old full size pickup running everything from county gravel roads, to 4 lane @ 70 mph, to an hour of stop and go city traffic.
MMO is my choice based on what I perceive as acceptable improvement in actual use.

 

[Dan in MI]

Years ago there was an issue with dirty fuels overseas causing a large build up on the back of intake valves. (I worked in export markets) This build up would absorb fuel and after a certain amount of time cause an intake backfire. That would clean it up for a little bit (hours) and then the cycle would repeat. We tried many different things to find an easy fix including many different cleaners introduced into the air induction system. Some helped, some didn't but none really cleaned the valves. The final fix was walnut shell blasting.

 

[Dave P.]

Not sure on the Honda engine asked about but some are set up with the valve timing to allow a bit of blowback if you want to call it
that into the intake tract to possibly help wash the valve stem area. The high detergent fuel additives might/might not help in this
situation. With out bore scoping the port and valve area and then driving the car a few thousand miles with additive in it you'll
never know. Higher mileage engines may have more oil blow-by which would also contribute to the buildup.
As posted by Dan above, right now only one sure quick solution.

 

[Hvymax]

Marvel Mystery Oil is what I use. I try to use it once every 5-6 tanks of gas. Sometimes when I'm running hard, I don't meet this schedule and will see a slight MPG loss but another treatment brings the MPG back to 'normal'.
This is fairly easy to see when driving same roads to same areas time after time. I just got back from a longer trip that involved a wide variety of driving conditions and roads. 17.5 MPG. May not seem like very good but this is a 20 year old full size pickup running everything from county gravel roads, to 4 lane @ 70 mph, to an hour of stop and go city traffic.
MMO is my choice based on what I perceive as acceptable improvement in actual use.

And it's minty fresh!

 

[RC44Mag]

Marvel Mystery Oil is what I use. I try to use it once every 5-6 tanks of gas. Sometimes when I'm running hard, I don't meet this schedule and will see a slight MPG loss but another treatment brings the MPG back to 'normal'.
This is fairly easy to see when driving same roads to same areas time after time. I just got back from a longer trip that involved a wide variety of driving conditions and roads. 17.5 MPG. May not seem like very good but this is a 20 year old full size pickup running everything from county gravel roads, to 4 lane @ 70 mph, to an hour of stop and go city traffic.
MMO is my choice based on what I perceive as acceptable improvement in actual use.

MMO wouldn’t help in the OP‘s case. His engine has direct fuel injection which shoots fuel directly into the combustion chamber so no fuel( or inj cleaner) at all touches the valve stem, intake ports or backside of valve.

 

[Dan in MI]

Not sure on the Honda engine asked about but some are set up with the valve timing to allow a bit of blowback if you want to call it
that into the intake tract to possibly help wash the valve stem area. The high detergent fuel additives might/might not help in this
situation. With out bore scoping the port and valve area and then driving the car a few thousand miles with additive in it you'll
never know. Higher mileage engines may have more oil blow-by which would also contribute to the buildup.
As posted by Dan above, right now only one sure quick solution.

The “ blowback” is a form of EGR for emissions. Inert gas to reduce combustion temperatures.

 

[noahmercy]

I think the old hot rodder's trick of using water works about as well as any of the elixers specifically designed for the task. Seems like some folks have had success with carburetor cleaner as well; vids on YT, if they're to be believed. What does emulsify carbon, but ruins O2 sensors and catastrophic perverters are the decarboners intended for small engines and two-strokes, like Engine Tuner.

 

[graygun]

My car gets the "Italian tune-up" in that I have to drive on I-10 about 55 miles to get to Kerrville,where the larger stores are. The speed limit is 80mph for the first 38 miles and then drops to 75. I drive in the 80s and 90s and might flirt with 100 or so for a few moments. I go there about two or three times a month. There's nothing much out here but prickly plants and such.

It's dropped to less than 30mpg just fairly recently.

I know BG makes a kit like the one mentioned above that involves a longer infusion,using a liquid into the intake tube,downstream from the throttle body. They also poured two cans of their costly stuff into the gas tank as part of the overall process. Car Wizard (a good Youtube mechanic with a large shop in Kansas) had some some guys there doing the process. They did not scope anything before or after. BG 44K is known to be a pretty good solvent.

I changed the plugs at 101K in June and they looked very good in color,with very little gap-widening.

 

[Dave P.]

The “ blowback” is a form of EGR for emissions. Inert gas to reduce combustion temperatures.

So with no fuel in the intake port is the buildup just caused by the crankcase blow by being evacuated into
the combustion air and building on the valve stems?

 

[Rat76]

Why wouldn't something delivered through the intake help clean the intake valves? It would. It would not clean the injectors but that's not what the OP asked.

I would look elsewhere for your MPG. Unless that engine is a known carbon trap (like a GM 3.6), it's not the cause of your issue.

ASE Master
GM World Class
30 years experience

My Honda experience is limited to '03, '07 & '11 CRVs. There a couple of non engine things that come to mind. Front transaxle fluid, changing is easy on the CRV, drain plug at front & no filter. Rear differential fluid in the case of an AWD.

The rear differential was an issue when I got the '03. The AWD on these is kinda neat. The rear end has a fluid clutch, there is a constantly spinning driveshaft from the front transaxle to the rear end, as long as the wheels are turning at the same speed the fluid has a very low viscosity. When the front or rear wheels slip causing them to rotate faster the fluid heats up, viscosity increases & the fluid clutch engages.

If your fluid is getting dirty the rearend will engage, at least part of the time, causing a drag on the engine. A grumbling growl from the rear is a good sign of this.

My '03 is actually an Element but I understand it & the CRVs are basically a Civic.

Cleaning the mass airflow sensor would be a good idea.

 

[graygun]

The older--port injection-- systems would help keep the intake valves clean by the injectors being close to and aimed at those---with the gas spray doing its cleaning action as a natural part of the operation. Yes,the crankase fumes (oily) are being sucked into the intake tube but w/o the benefit of gas being sprayed onto the tops of them as they are opening.

I've heard Toyota has newer stuff with both port and direct injection.

I'll clean the MAF sensor.

 

[sfhogman]

So with no fuel in the intake port is the buildup just caused by the crankcase blow by being evacuated into
the combustion air and building on the valve stems?

Correct.

 

[RC44Mag]

A catch can would help, think I’m adding one on my S/C’d Vette

 

[turd]

A catch can is the answer. Don't know why manufacturers can't figure this out. Easy to install, but they aren't really cheap. Pretty much around $150.

 

[RC44Mag]

A catch can is the answer. Don't know why manufacturers can't figure this out. Easy to install, but they aren't really cheap. Pretty much around $150.

My Vettes been in the shop all summer after grenading the transmission. Looks like I’ll finally get it back next week. It going to cost a pretty bundle so I’ll add the catch can next year.

 

[GasGuzzler]

A catch can would help, think I’m adding one on my S/C’d Vette

I have a catch can on my 2007 Sierra 5.3. Pretty amazing how much it catches.

 

[RC44Mag]

How often you emptying it?

 

[GasGuzzler]

2-3K miles. Probably catches 1/8 cup per 1K.