Decarboning the engine---

takza · Post by **takza** » Tue Apr 06, 2004 2:23 pm

Seems the Tercel 1.5L engine might be senstive to pinging and dieseling due to the fact that it runs lean by design...or what?

At any rate, the engine tends to build up carbon deposits and/or the EGR tends to stick causing poor running and dieseling and so forth.

If your engine uses oil to any degree...decarboning it could help it a good bit.

I've heard of several methods to decarbon the engine (besides taking it apart), all involving putting liquids of various kinds into the intake as the engine runs.

The method I use:

1) Find a plastic dish soap container that will hold 1 pint or more...use a marker to mark the 1 pint level by filling the clean container with 1 pint of water and marking this level...this is the fill line.

2) Dump about 1/8th of the water out and add some Marvel Mystery Oil or AutoTransFluid back to the fill line. Use a 1 to 8 ratio of oil to water. Then add around 2-3 drops of dish detergent. Put the cap on and shake the bottle to emulsify the mix.

3) Remove the top of the air cleaner and filter; and then start the engine. With the choke open (engine slightly warm) & the engine reving at around 2000 RPM start squeezing this mix into the left carb barrel (passenger side) thru the SMALL NOZZLE on the container. Shake occasionally.

4) Do this until you use up the full pint....being sure to keep the engine from stalling...you might need to stop the flow at times to keep it running. Don't over rev it!

5) When done, take the car out for a spin to clear out the carbon, oil, & water.

Other methods involve basically the same thing, only using ALL MMOil, ATF, SeaFoam, Rislone, etc. These are all high detergent lightweight oils. Best used in winter when the water/oil mix might freeze.

Using ALL oil will cause great clouds of smoke to pour out and might upset your neighbors. The water / oil mix doesn't put out so much smoke.

Other things to do:

Now that the carbon is out, you could take advantage of this to advance your timing some for a little more power.

Also...might be best to do the decarboning before an oil change. Also it's possible that a plug might foul from the carbon being thrown around...remove & clean.

Would be reasonable to do the decarboning before each oil change. or maybe 2Xs per year.

GTSSportCoupe · Post by **GTSSportCoupe** » Tue Apr 06, 2004 3:08 pm

Thanks for the great write up!

icE · Post by **icE** » Tue Apr 06, 2004 3:33 pm

Awesome writeup! I'll save it for the site

Thereminator · Post by **Thereminator** » Tue Apr 06, 2004 9:10 pm

All Hail Captain-Chemical!!! Long-Time Foe of EVIL-CARBONATOR!!!!

tercel4wdrules · Post by **tercel4wdrules** » Thu Apr 08, 2004 9:21 pm

Will running your engine hard oh say... use a cement foot and do maximum speed in each gear help knock carbon off? Or will it cause some serious damage?

takza · Post by **takza** » Tue Apr 13, 2004 5:29 am

tercel4wdrules wrote:Will running your engine hard oh say... use a cement foot and do maximum speed in each gear help knock carbon off? Or will it cause some serious damage?

Probably works and is also more or less a good excuse to go out and drive like hey.

Could do some damage if you have a lot of carbon buildup and have serious pinging.

My theory (probably heard somewhere) is that there are nano-spiders that build webs in our engines AS WE SLEEP! So, it is necessary to run an engine fairly hard to defeat their nefarious intentions.

It just goes to show you...there's always an excuse to go fast.

tercel4wdrules · Post by **tercel4wdrules** » Wed Apr 21, 2004 2:06 pm

Well I don't think it is necessarily necessary to go that fast. You can do 4.5K RPMs in 1st and do 4K in 2nd gear and you might not get to go over 35 MPH anyway, so you don't have to go that fast. Why would it do some damage if there is severe pinging or if you have a lot of carbon buildup?

takza · Post by **takza** » Sun Apr 25, 2004 5:35 am

tercel4wdrules wrote:Well I don't think it is necessarily necessary to go that fast. You can do 4.5K RPMs in 1st and do 4K in 2nd gear and you might not get to go over 35 MPH anyway, so you don't have to go that fast. Why would it do some damage if there is severe pinging or if you have a lot of carbon buildup?

It's not the car's speed that matters, but the engines.

Carbon/gum/varnish tends to gum up the rings on the piston...causing them not to seal as well as they should. Also it does the same on valve stems, causing them not to close as fast as they could. A lot of carbon can increase your compression ratio and cause hot spots (glowing carbon)...which increases the chances for pinging.

Pinging is gas/air mix that is burning too soon and actually working against the piston as it comes up on the compression stroke...slowing you down and maybe doing some engine damage.