Can revving the engine help clean out carbon buildup?

[Ducaire]

My '02 Camry (2.4L engine) has 233k miles on it, and I've noticed it's lost a little bit of power when accelerating (it still seems to to find at road speeds), even though I just had a new air filter installed recently.

My mechanic suggested taking it out on the interstate around 70-75 mph to help get the rpms up and blow some possible carbon buildup out. The only thing is that this vehicle has spent and still spends most of its life at 55 mph with the engine at 2,000 rpms (not much stop/start driving or idling). Do you think this will help?

Another question is, if I were to drive with the overdive turned off, would this be bad on the engine or transmission as long as I were careful not to drive too fast (50-55 mph at the most)?

Ps, I'm one of those drivers who uses their big toe to accelerate; I'm careful to not let the engine get over 2,500 rpms. The execption to this is cruising on the interstate, as I believe the engines turn at 2,600 rpms at 70 mph.

[Brian R.]

I think that blowing out the carbon was a necessary fact when there were carburetors. Engines don't build up carbon with the precise fuel metering of the modern fuel injection systems.

Driving with the overdrive off will not affect anything as long as you don't overrev the engine.

Check the compression to see if you are loosing power there. There are other sensors which could lower your power if they are not doing their job as well as new, such as the engine coolant temperature sensor, knock sensor, air/fuel ratio sensor, maf meters, leaks in the intake intake, many small differences add up.

Also, consider the possibility that it is just warmer outside than when you are comparing the performance. Hotter air temperature will lower power.

[MikeCStig]

Bringing the engine to higher RPM on a fairly regular basis does help keep the engine cleaner. Once the damage is done however, I'm not sure that revving the engine higher will clean it out. At this point I'm not sure there is an easy fix.

[somick]

Originally Posted by Brian R.

I think that blowing out the carbon was a necessary fact when there were carburetors. Engines don't build up carbon with the precise fuel metering of the modern fuel injection systems.

Driving with the overdrive off will not affect anything as long as you don't overrev the engine.

Check the compression to see if you are loosing power there. There are other sensors which could lower your power if they are not doing their job as well as new, such as the engine coolant temperature sensor, knock sensor, air/fuel ratio sensor, maf meters, leaks in the intake intake, many small differences add up.

Also, consider the possibility that it is just warmer outside than when you are comparing the performance. Hotter air temperature will lower power.

What Brian said.

Plus you never mentioned the regular maintenance.

How old are your spark plugs?

Have you ever cleaned the throttle body.

What are the conditions of the ATF?

Good luck,
Sam

[Stealthee]

Originally Posted by Brian R.

I think that blowing out the carbon was a necessary fact when there were carburetors. Engines don't build up carbon with the precise fuel metering of the modern fuel injection systems.

Driving with the overdrive off will not affect anything as long as you don't overrev the engine.

Check the compression to see if you are loosing power there. There are other sensors which could lower your power if they are not doing their job as well as new, such as the engine coolant temperature sensor, knock sensor, air/fuel ratio sensor, maf meters, leaks in the intake intake, many small differences add up.

Also, consider the possibility that it is just warmer outside than when you are comparing the performance. Hotter air temperature will lower power.

I disagree that carbon buildup isn't an issue on fuel injected engines. I have torn down or been witness to several torn down engines and the carbon buildup on valves and pistons is no different on fuel injected that it is on carbureted.

The best way to clean the carbon out, without invasive procedures is to use something like Seafoam. You let it suck in through a vacuum line and let the car sit a few minutes and the white smoke show you are left with is indeed carbon burning off the valves and pistons.

[Brian R.]

Originally Posted by Stealthee

I disagree that carbon buildup isn't an issue on fuel injected engines. I have torn down or been witness to several torn down engines and the carbon buildup on valves and pistons is no different on fuel injected that it is on carbureted.

The best way to clean the carbon out, without invasive procedures is to use something like Seafoam. You let it suck in through a vacuum line and let the car sit a few minutes and the white smoke show you are left with is indeed carbon burning off the valves and pistons.

Don't ignore the fact that the engines you are talking about were in need of major maintenance. To me, that means that it was not running right in the first place and probably not driven normally. I was referring to engines which are operating normally. There is no reason for carbon to build up in the cc when the fuel/air ratio is tightly controlled by a fuel injection system. Burning oil and excessive blow-by can cause this, but it is not a normal engine if it has these problems.

If you have carbon build-up in a fuel-injected engine, removing the carbon is the least of your worries.

[Stealthee]

Originally Posted by Brian R.

Don't ignore the fact that the engines you are talking about were in need of major maintenance. To me, that means that it was not running right in the first place and probably not driven normally. I was referring to engines which are operating normally. There is no reason for carbon to build up in the cc when the fuel/air ratio is tightly controlled by a fuel injection system. Burning oil and excessive blow-by can cause this, but it is not a normal engine if it has these problems.

If you have carbon build-up in a fuel-injected engine, removing the carbon is the least of your worries.

Just because an engine is torn down, doesn't mean it was in need of major maintenance. I tore down the engine in my Stealth, just cause. I had everything else ripped out of the bay and figured I would regasket the engine while it was out. The cylinder walls were perfect, compression was normal, yet there was a large amount of carbon on the valves and piston tops.

A lot of manufacturers make their cars run a little rich as a failsafe, that rich condition is going to cause carbon. I have seen many other engines torn down to be built, not because they broke, and almost all had the layer of carbon on the pistons and valves.

[Brian R.]

Originally Posted by Stealthee

Just because an engine is torn down, doesn't mean it was in need of major maintenance. I tore down the engine in my Stealth, just cause. I had everything else ripped out of the bay and figured I would regasket the engine while it was out. The cylinder walls were perfect, compression was normal, yet there was a large amount of carbon on the valves and piston tops.

A lot of manufacturers make their cars run a little rich as a failsafe, that rich condition is going to cause carbon. I have seen many other engines torn down to be built, not because they broke, and almost all had the layer of carbon on the pistons and valves.

Ok, your engine runs rich. It better. It is a real stretch of the imagination to think your engine is burning a mixture anything like that of a 2002 Camry 2AZ-FE, or any engine built for economy or reliability. I don't believe you will find any meaningful carbon deposits in the cc of a 2AZ-FE that is torn down for the hell of it. For that matter, some engines run normally with a lot of blow-by. Those don't count. They will always have carbon, even with 10k miles on them.

[Stealthee]

I'm not trying to be a smart ass, but here is a vid of a 98 Camry that used Seafoam. All that white smoke is carbon burning off the valves.

https://youtu.be/Ulsubnl6JQo

Carbon is not as bad in fuel injected cars as it was in carbureted, but it still happens, and hell GDI cars are KNOWN for carbon issues because of the way the fuel is injected.

[Brian R.]

Originally Posted by Stealthee

I'm not trying to be a smart ass, but here is a vid of a 98 Camry that used Seafoam. All that white smoke is carbon burning off the valves.

https://youtu.be/Ulsubnl6JQo

Carbon is not as bad in fuel injected cars as it was in carbureted, but it still happens, and hell GDI cars are KNOWN for carbon issues because of the way the fuel is injected.

The 5S-FE in that car is known to have huge blow-by. Not a good example.