My wife has a 98 expedition with a 4.6L. It has recently began to ping (labor knock) when under a load. A friend sugested that the throttle body might have carbon build up. I removed the air intake and the throttle body. There was a small amount on the butterfly looking valve. Beyond that the area where the egr lines are attached there were to long pieces of carbon which looked like part of a coral reef. Have been running 87 octane gas. I am sure there is some buildup on the pistons and valves which is causing the labor knock.
1) How can I remove that buildup?
2) Does using premium gas prevent this buildup in these engines?
Is it normal for the trition engine to build up carbon in this way?
Thanks in advance to anyone who can help!

 

This is a common problem with the 4.6 intake. Driver side oil fumes and the egr turn the intake elbow into a toilet. Even though the throttle body doesn't look that bad, the apertures for the IAC and EGR become restricted and it just effects everything downstream. I have gone as far as disassembling the entire intake down to the heads. There is an easier way, and it costs about $10. Seafoam and Deep Creep is available at napa and marine stores. I bought a purolator PCV valve at Pep Boys and 5 ft of aquarium tubing.

The motor must be cold.

Remove The factory PVC valve on the passenger side and cover the hole in the valve cover with duct tape.

On the new PCV valve, there are 3 connections. Insert aquarium tubing on the small one that would be plugged. Cover the bottom of the valve which would usually be in the valve cover with duct tape. Connect the ususal connection to the PVC suction hose that leads toward the firewall.

Put the aquarium hose in the seafoam, placing the bottle somewhere it wont spill (Flammable).

Remove intake pipe to expose throttle body. Spray intake elbow with deepcreep, especially at the top. Reassemble intake.

Get inside and start the truck until it stalls. Make sure you drew in a decent amount from the bottle. Wait 20-25 min. Close the windows of your house and warn the neighbors.

Crank the motor until it starts and rev it up. The carbon will be shot out your tailpipe. When it clears up some, reassemble the PVC system and go for a ride to get up to operating temperature.

This should cure most non-mechanical carbon fouling problems. I do not recomend the use of hi octane if you do not require it. The heavy molecular chain deposits more carbon than 87 octane. Your PCM makes no use of it anyway.

I think this is the most effective way, if it doesn't work- find out your computer code in the pass door jam and locate your octane shorting bar.

 

The TB neck is what usually gets clogged the most on the 4.6L. remove the TB, and then remove the TB neck. you'll have to remove the EGR valve also. you will see the two small holes that dump into the combustion chamber are clogged. you'll most likely have to scrap that stuff out. buy a new egr casket(its like a $1) and take your time. this is not hard to do, but time consuming. also buy a can of TB cleaner(make sure its coating safe) to spray into the ports also... you won't believe the build. you'll wonder how the EGR system was working at all.

 

The factory manual that came with my 97 F-150 4.6L says that if you use 87 octane, expect some nocks and poor performance. The manual recommends using 89 octane.

My local Ford Service department told me "if you're too cheap to use 89 octane in your V8, at least run one tank of 91 octane through it every oil change to clean things out."

 

They must be smoking some serious crack at that dealership.
Higher octane will not clean an engine out.

In addition to the recommended tips above, the PCM can also be reflashed for the lower octane.
There may also be an octane adjusting plug you can remove to retard the timing 3 degrees. It is located behind the battery in the harness going to the PCM-there will be a small gray plug (2 wires) that you can remove.

 

Never seen gas remove carbon myself. I guess if you use it for the solvent along with the drill bit it will work. I guess that is where 91 octane will shine over 87.

I would dig it out and then do the Seafoam thing. I don't think the Seafoam will make it through the EGR soon enough to clean those ports in the TB elbow.

A drill bit should work. Don't put it in the drill turn it by hand.

 

In my 2000 F-150 with the 4.6, I have been using a product called RXP from O'Riley's, once a month, and also 1 quart of Essential Lube, made by Hydrotex both products in the gas tank once a month. The truck is at 83,000 miles and so far no problems with carbon build up.

 

Thanks guys for the response. I did the Deep Creep and Sea Foam treatment. It smoked quite a bit and then ran fine. However the pinging (labor knock) is still very present. It actually got a lot worse right after the cleaning. It does not ping on high octane gas. Any more info on how to re-program the octane sensor?

 

Just a thought, If the truck was running a little hot it could cause it to ping under load. How is the cooling system? I have heard it from many here that the gauge works more like a light than an actual gauge. I would also think thaat the knock sensor would be retarding the timing and not letting it ping. Of course if it retarded it enough you would have performance problems too.

 

I've tried all these products and more and have found the only one that works the best and does more for a car is FUEL POWER. Dyson Analysis did a study on it and had great results. I also use LUBE CONTROL with great results. No more pinging for me.

 

I have been fighting the ping on my 5.4 every since I got it. I finally got it fixed right and the dealer flashed the PCM and it now runs 87 ocatane with only the occasional really light ping when loaded heavy.

The dealer did this for free. I was told by the dealer that there is an 8 year/80,000 mile warranty on the PCM.

If those two ports are plugged then that will be the pinging you are getting though.

tom

 

Has anyone taken a picture of the two ports that get clogged with carbon?

 

here is the website for Fuel Power www.lubecontrol.com this is good stuff and will decarbon any gas or diesel engine.

Lube Control also works wonders with your oil.

also read about it at http://theoildrop.server101.com/ubb/...?ubb=forum;f=5

 

I don't belive this is accurate.... My 98 recommends 87, and I've never heard of a 4.6 or 5.4 that recommends 89 stock from the factory.

 

I have a 93 F150 with a 302 and it does the same thing. Will this work on my engine as well.