Help With Carbon Build-up...

[DTS419]

So I have a 2001 Silverado with the 5300 engine and about 66,000 miles on it. I just got it about a month ago. It runs great and was well taken care of and had it's service done religiously. The only trouble I am having with it is some detonation at high RPM. If I am going about 40-50 mph and floor it to pass someone, causing the RPM to jump up to 4,000+, the engine detonates like they did in the old days when you had the distributor too advanced. It's a certified pre-owned under the 3,000 mile warranty so I took it back to the dealership. They drove it, verified my concern, and I guess monitored everything with the computer. The results were that everything was operating as normal. They suspected the cause was carbon build up and did their fuel system cleaning treatment, and also put some special additive in the gas. They said by the time I went through that tank of gas, all carbon should be gone. Well the problem is, I have gone through that tank of gas, plus half of another tank- this time I added two bottles of Seafoam. I have also tried the method of sucking Seafoam through the break booster vacuum line, and I am still getting the detonation. It does seem to have gotten a little bit better, but is still very obvious...

 

Is the dealership right that these engines are prone to carbon build up?

What would cause this after only 66,000 miles and how to prevent it from getting worse or coming back?

 

And the big question... Will any of these additives work or is there any way to remove the carbon short of ripping the engine apart for cleaning?

 

I run 87 octane like the book says and the only thing I haven't tried is higher octane fuel, but #1 I don't want to get stuck paying for more expensive gas for the life of the truck and #2 I have read that using fuel with too high octance can actually cause carbon build up (maybe previous owner was one of those guys who thinks he's doing well buy always using premium gas...)

 

Any thoughs or comments will be appreciated.

[nbscanuck]

Clean the MAF with proper MAF Cleaner

[bill190]

Here is a web site just for this problem...

http://www.pistonslap.com

[DTS419]

Clean the MAF with proper MAF Cleaner

 

 

such as??

[Stevens03]

The Mass Air flow Sensor gets dirty and can cause all kinds of minor issues. If you clean it with a good electrical contact cleaner, it may fix your problem. You spray the honey come and the elements with the cleaner making sure NOT to touch the elements with your hands. Re-install and see if that helps. It should only take you a few minutes to clean and re-install.

 

I certainly wouldn't let it ping alot, I would consider bumping to 89 octane for a little and see if that fixes/helps the problem too.

Good luck

[DTS419]

The Mass Air flow Sensor gets dirty and can cause all kinds of minor issues. If you clean it with a good electrical contact cleaner, it may fix your problem. You spray the honey come and the elements with the cleaner making sure NOT to touch the elements with your hands. Re-install and see if that helps. It should only take you a few minutes to clean and re-install.

 

I certainly wouldn't let it ping alot, I would consider bumping to 89 octane for a little and see if that fixes/helps the problem too.

Good luck

 

 

So a dirty MAF sensor could cause detonation at really high RPMs while the engine runs like a raped date the rest of the time?

[jbordi]

I would also try the MAF sensor. CRC makes some cleaner for MAF sensors now. My 01 Blazer was giving many engine performance problems before I cleaned the MAF.

 

May also want to clean the throttle body.

[REV353]

Get 2 cans of Amsoil Power foam. When your engine is at running temp, spray it into your intake, you might have to rev up the motor by hand or it will kill. Spray the whole can into the motor, when the can is nearly gone choke off the motor or shut it off. Let it sit about a half hour to and hour. Make sure you do this in a open area, then start it up & let it idle for a min or 2 then rev the truck up to clean out the system. This will take care of any carbon, I do this about once a year, I also take the second can and spray about half of it into the gas tank with a half tank of fuel. One last thing, spray it after the MAF sensor.

[REV353]

For got. Sea-foam sucks!!

When gas sits with sea-foam in it, the sea foam clings on to the gas additives and turns into a jelly, it takes 3 times as long to clean out a carburetor that has had that crap in it than having nothing at all. Just buy a product that has one purpose, it will do a better job.

[Jennabear]

Did you let the Seafoam soak? We usually let it soak for 5mins or so, be sure to change the oil when you are done. Might have to do a few rounds of Seafoam if your system is really gunked up. Or you can always drive your truck real hard for a while, a couple of full throttle blasts can do wonders.

[REV353]

Power Foam Engine Cleaner & Degreaser (APF)

AMSOIL Power Foam removes gum, varnish and carbon deposits for more efficient fuel economy and improved overall engine performance. AMSOIL Power Foam cleans intake valves, intake manifolds and throttle plates to keep the combustion intake system running at peak efficiency. Effective in both two-cycle and four-cycle engines, AMSOIL Power Foam eliminates engine ping and keeps carburetors and injector systems properly tuned. AMSOIL Power Foam is safe for fuel injectors, catalytic converters and emission control devices. It will not damage seals, gaskets, rubber or plastic materials commonly used in gasoline engines.

 

AMSOIL Power Foam contains a powerful foaming agent and special high boiling solvents that penetrate rust and grease. It cuts through rust so bolts can be loosened or tightened easily and washes clean, leaving no residue to attract dirt. Power Foam also helps reduce pollution caused by dirty, rough-running engines.

 

See Pricing Information or Place an Order Package sizes include:

 

 

 

18-oz. Spray Can

 

18-oz. Spray Cans (case of 12)

 

 

Performance Features

 

 

• Removes gum, varnish and carbon deposits
  
• Suppresses engine ping
  
• Cuts through rust and grease
  
• Helps improves fuel economy
  
• Reduces Pollution
  
• Frees stuck choke mechanism
  

DIRECTIONS

Run engine to normal operating temperature and remove air cleaner assembly. While engine is running, spray entire can of foam directly into intake. Turn off engine and allow to sit for 5-10 minutes. Restart engine and drive to blow out deposits.

 

RECOMMENDATIONS

Avoid contact with hoses. To prevent the dissolving of paint, do not overspray. AMSOIL Power Foam is not recommended for use in diesel engines.

[DTS419]

I let the Seafoam soak for 5-10 minutes. I know people swear by Seafoam, but I'm a little skeptical of "fix in a bottle". I just can't picture some liquid running through the intake being able to wash away all that baked-on carbon without any agitation. I am wondering if the fuel additives live up to their claims as well...

[txab]

You can also check your knock sensors

[DTS419]

Let's step back here for a minute and re-examine the problem. My problem has been assumed to be carbon build up, but in searching the archives here, most of the people who have had detonation related to carbon build up experienced different symptoms. Many claimed to get the detonation at light throttle or when "lugging" the engine. However, mine only detonated at high RPM and does not do it at all when lugging or light throttle, going up hill in low RPM, etc. Runs like a champ until I floor it and hit 4,000 RPM.

 

I suppose that when the engine is at really high RPM, this causes a greater advance in the spark timing, and any carbon that is present could be creating a higher compression that only causes detonation during this rare time of advanced spark. Perhaps the case of detonation at light throttle or daily driving is a worse case of carbon build up and maybe a lot of guys don't realize it at the stage I am experiencing because most people don't floor the truck at 4,000 RPM every day. Anyway, just brainstorming here...

[Draenor]

There are numerous factors the ECM uses to advance/retard timing. Are you getting any DTCs, especially at the high RPMs? Have you pulled the plugs and inspected? Have they been replaced previously(since you bought used). Is the EGR working properly?