In one of his previous posts, CowboyBilly09NineMile said something about removing all the carbon from his engine. How is that done? This may be a really simple question but I've never heard of doing it, except just running at high RPM for a period of time.

 

You can use a product called Seafoam, or even a water mist, into the intake while the engine is at a high idle to de-carbonize an engine. The negatives to doing this, you can plug the CATs, or damage the O2 sensors.....

 

Can Someone explain why engines need to be de-carbonized? I mean, in todays engines that are so efficent with fuel management where does this carbon come from? If it is oil I could understand it, but from the posts I have seen oil useage is not a problem. It would seem to me that there would be very little carbon build up...
Dave

 

The 4.0 is vulnerable to carbon build up; it's just the nature of the beast. Over history, there have been a few other engines that also like to do it.

https://www.ford-trucks.com/forums/s...hreadid=100739

PM3 cleaner from Ford is the weapon (cleaner of choice). Follow that TSB to the tee and there should be no problems. After all, it's what the dealer does if you wheel it into their shop .

 

You are correct about the newer vehicles, compared to the order ones. It does however, depend on how the vehicle is driven. If a vehicle is only driven for short trips, where the engine never gets to operating temp, and the PCM stays in "open loop", then carbon will build up in the combustion chambers.

 

Thanks for info, always glad to learn something new.
Dave

 

I think some of it has to do with head design (combustion chamber). Even people who don't do short trips on a cold engine wind up with the problem. Like me on my old Ranger.

 

Extra deposits can be had by using premium fuels too, as our engines aren't designed nor timed to use the extra octane, so extra deposits can form.

Ford in my owners manual cautions against using premium fuel for these reasons, but folks do it anyway, thinking they are doing something good for their engines & the opposite could be happening.

Some gasoline formulations have more top cylinder light oil blended in & that with a slow stop & go (severe service) drive cycle could help exacerbate a deposit problem.

Others blend in just the bare goverment rquired minimum of detergents.

Still others use detergents that'll clean the intake side, but leave combustion chamber depsits!!!!

Using a good top tier gasoline with a good detergent add pack, like Chevron or Texaco, or the adding a additional cncentration of a good detergent, like Chevrons Techron Concentrate, or Texaco's Clean System 3, to a tank of gas, & a spirited highway run, can tidy things up inside too!!!!!

Like Billy was talking about, I have a 99 4.0L that is very intolerant of the sightest buildup of combustion chamber deposits, so I have to frequently alter my drive cycles & change the brand of fuel every 6 months, to keep it under control.

So far I've managed to keep it under control that way, without having to use the PM-3, SeaFoam, Techron, ect.

 

Extra deposits can be had by using premium fuels too, as our engines aren't designed nor timed to use the extra octane, so extra deposits can form.

I was getting a really bad pinging up till about a month ago when I started using the mid-grade gas. It stopped immediately, mostly. I think the octane rating is around 90 or 91 in those fuels. Is that still too high? I seem to remember something in the manual about the octane rating and it being a good thing. As in, I didn't need to worry about getting Premium all the time. I'll re-visit my manual. However, having this intermittant miss I've posted about could be from carbon? I'm at a smidge over 109,000 miles and I've never done anything to clean the motor except change plugs and wires, and the oil every 3,000 miles or so.

 

By going to a higher octane fuel, with positive spark knock results, it sounds like you may have combustion chamber deposits.

These deposits can cause an increase in compresson & result in a need for increased octane, so the engine won't ping.

Your origional question about how to do the 4.0L engine's de-carb prceedure Billy was talking about, with the PM-3, was covered by a Ford TSB proceedure, that required the SLOW induction of the cleaner through a vacuum line, into the intake manafold, so it could be evenly distributed to the cylinders & the TSB called for the proceedure to be repeated 3 times.

This proceedure is linked to, in a thread, at the top of this forum's main page, in the second "Read First" "Technical Thread", under, 4.0L decarb proceedure.

The dealer has done this TSB de-carbing proceedure to my 99 4.0L once, for a CCDI problem, it worked, but it didn't last long on my CCDI problem.

Removing the heads & decarbing them lasted me about 18 months, utill I ran 3 tanks of Shell's new gas, then the cold start up CCDI was back.

I immediately switched back to Chevron & it took about 3-4 tanks of that, to clear it up again.

Since 01, switching between Chevron & Texaco fuel, every 6 months has kept the Combustion Chamber Deposit Interference (CCDI) start up knock, at bay.

Now that Chevron & Texaco have the same detergent add pack (Techron) as of Aug 05, I'll have to find another fuel with a different, effective, detergent add pack.

So I can switch between the two every 3 K miles or every 6 months, to keep my 4.0L engine's deposit load in check.

It takes about 3 tanks of gas or 1000 miles of driving, for one fuels detergents, to remove the others deposits & keep our engines as clean as possible.

Of course, the other alternatve, is to dump in a load of a good detergent in the gas tank, like Techron Consentrate, ect, or do the PM-3 decarb proceedure & rev the heck out of it daily, to keep it clean & blown out.

So if you have a 4.0L, you can do the decarb TSB proceedure & change your daily driving habits, or add a fuel detegent now & then, or try switching brands of gas every 1000 miles or so & see how that does.

For me switching gas every 6 months has worked well for the last two years or so!!!!

The de-carb TSB proceedure is really for spark knock problems, like you apparently have, not the mechanical CCDI problem I have. But if switching gas brands keeps the engine deposits down for me, it should help a deposit caused spark knock problem too, assuming, spark knock IS your problem!!!!

 

It's also my understanding that taking her up above 3000 rpm at least once a day helps to keep it cleaned out. Wouldn't rely on it as a perfect method of course, but does help apparently.