Bob, I'm not following you on why water could ruin the O2 sensor or damage the catalytic. Water injection is used on some turbo motors with no problems of that type (that I'm aware of, at least). Can you elaborate on that?

 

Hi Fastpakr,

With water, it's not a chemical problem that damages the O2 sensor and CAT. With heavy carbon deposits, it a mechanical
damage problem with the O2 sensor, and with the cat, the
carbon "debris" can plug it up.....I hope this answers your
question..

Bob

 

I understand the concept of carbon debris damaging the catalytic, although I'm not sure why it would be worse with water than other cleaning agents. What 'mechanical damage' could occur to the O2 sensor?

 

Hi Fastpakr,

I think water would be about the same as other cleaning agents.
Depending on the size of the carbon particles, they could physically damage the active element in the O2 sensor, as well as plugging up the CAT.

 

Well pawpaw has/HAD the same CCDI problem with his 99 4.0L.

Here's how I've solved my problem.

Ford dealer did the TSB Decarb thing with PM-3, which has plenty of water in it, check the MSDS.

This only worked for a few weeks, then the cold knock was back.

After a head gasket replacement, & decarboning of the heads & pistons during that gasket replacement, the CCDI was gone for 1 year then returned after 3 tanks of new formula SHELL.

After talking to a local chem engr who's job it is to mix fuel aditives for a major oil company, about fuel additives & CCDI, (Combustion Chamber Deposit Interference), I do the following.

At every oil change, I switch between the two best performing fuels.

As it takes about 1K miles for one fuel brands additives to remove the others deposits, changing brands every oil change is easier to remember & about the right time frame.

Currently the two best performing fuels in my ride here in SW Va is Chevron & Texaco.

In my Ranger they beat the others by 2-4 mpg.
Chevron currently being the best.

This switching between the two best performing fuels,
& doing the 2-3 mile above 3500 rpm, blow out every now & then, has kept pawpaw's 4.0L CCDI knock free.

Try it, you too may be as pleasantly surprised as I.
pawpaw

 

Bob ayers,
Is the 3.0 in my '97 Aerostar the same as your Ranger? You recommend the Motorcraft AGSF12PP for your 3.0. Would they be the same for my 3.0?
Thanks, Beaned

 

Hi Beaned,

No, your 3.0L would take a different plug, my Ranger 3.0L is a FFV,
which takes a different plug....

 

Hi Bob,
Would you know offhand what the number would be for my 3.0
Thanks, Beaned

 

Hi Beaned,

I just checked the Motorcraft website, and it's calling out the
AGSF32FM, which is the new "fine wire" platinums.

 

Thanks Bob, for going through the trouble...
Beaned

 

Here's a link to a picture of the vacuum line CowboyBilly9Mile talks about in his post.

Vacuum Line Location

 

CowboyBilly9Mile (or anyone knowledgable about this), I beleive I have the carbon buildup problem with my '99 Ranger 4.0. The instructions say to repeat the procedure 3 times.... Does this mean I need to pump 3 cans of this stuff into the motor? It seems excessive, but if thats what I need to do, I will do it. Just wanted to make sure I'm reading this correctly.

Thanks in advance.

Snydly

 

Snydly, you got her right, the TSB says do it 3 times, so you need 3 cans of the PM-3.

Also don't forget to change the oil & filter after doing this proceedure.

There'll likely be plenty of crud boken loose, thus plenty of chemicals & particles in the oil & filter.
There's lots of water in the MP-3

I have had the dealer do this TSB on my 99 4.0L while it was still under warranty.

It didn't stop the knocking for long, for me.

Only after they replaced the heads & head gaskets for water use & during that work, dearbed the engine in the process, did it STOP the knocking.

I've managed to keep the carbon knock at bay by switching between the two best performing regular fuels, Chevron & Texaco, for me in my area, SW Va.

I used 3 tanks of new fomula Shell regular last summer & the knock returned.

I immediately switched back to Chevron, it took about 3 tanks to clear it up again.

I'll switch back to Texaco at this oil change, then back to Chevron at the next change.

Switching back and forth at each oil change, enables each fuels additives to clean up the ohers deposits, before they get too heavy.

It will take about 1000 miles of driving, for one fuels detergents to clean up the others deposits. So it's just easier for pawpaw's grey mater to remember to switch fuels at each 3000 mile oil change & so far it's been soon enough.

Also do the above daily 3000 rpm 3 mile blow out, outlined in the TSB. Doing this & switching between the two best performing fuels has kept pawpaw's 4.0L knock free for the last 18 months.

Maybe it'll work for you too. pawpaw

 

Pawpaw,

Thank you for the useful information. I plan on changing sparkplugs, oil and filter after this. I also plan on changing fuels as you suggest as part of my preventative maintenance plan.

I am wondering, however, if I should be using mid-grade fuel. I live in Denver, and all fuels have lower octane ratings here due to the higher altitude (low-85 mid-87, and high-89or90). Should I stick to the recommendation of using low-grade even though it has a lower octane rating?

Thanks again.

Snydly

 

Snydly, In the decarb TSB, Ford doesn't recomend mid or premium fuel in our 4.0L, because of extra deposits those fuels can leave, which would likely make things worse.

I use only regular. I've tried several different brands.

In my area, the way they blend the additives, Chevron then Texaco perform the best for me.
Texaco gives me about 2 more mpg & Chevron bout 4 more mpg over other brands.

The rest, Exxon, BP/Amaco, Shell, Crown, Citgo, give me less mpg & some driveability problems, so I don't use them.

As I posted before, the new formula Shell brought the CCDI knock back after 3 tanks last summer. So I stay away from it now.

Most of my Texaco stations have turned into pumpkins (Shell stations) so it's more difficult for me to find Texaco now.

The Texaco web site says they intend to re-enter the U.S. fuel market in July this year, so maybe I can get some good gas again soon.

You'll just have to try different brands & keep mpg figures to determine which one works best for your engine, in your area & for your kind of driving.

Then swap between those two every oil change.

Would be interesting to hear which ones work best for you, out in mile high Denver.