How do you clean the Carbon out of the Intake Manifold Gallery?

This is a separate thread from my others about the Head rebuild and the Ring
Replacement...

I have posted some threads about obtaining a used Intake Manifold (IM) and TBI
from a "Pull-n-Save" this last winter. The tube or gallery from the Block thru
the Intake Manifold, thru the EGR and back up to the TBI was packed solid with
Carbon!

Having just taken my own IM off to rebuild the Head, I found exactly the same thing!

Not wanting to diassemble all of the IM tubes and sensors, does anyone have
any suggestions on how to get all that damned Carbon out of the IM passageway
from the Head to the EGR and so forth?

On the Pull-n-Save unit, I picked the Carbon out of the EGR by hand
with dental picks! But I never figured out how to clean out the IM passageway.

Intake side View - From Head to EGR VAlve
http://img219.imageshack.us/img219/1913/fromheadtoegrcj0.jpg

From other side
http://img219.imageshack.us/img219/9408/fromheadtoegr2tr3.jpg

Bottom side view
http://img219.imageshack.us/img219/5059/headtoegrbottom2oa4.jpg

From EGR Valve to Throttle Body Unit view
http://img217.imageshack.us/img217/1005/egrtointakeec4.jpg

All this is full of Carbon - either solid packed or with a lot of carbon...
Sinuous curved passageways.... I don't want to cut the Aluminum up doing it.

I have to come up with a method of cleaning it out. Any Suggestions!?

DoctorBill

I'd like to know, too. I used a coat hanger, pipe cleaners, Gumout, time (filling it up w/Gumout & letting it sit at the angle where both ends are at same level), and compressed air, and hoped I got the passage cleared.
I took off the valve when I did this and cleaned it too as best I could. Then I replaced the gasket & put the valve back on.
BTW, someone said not to use anything but plastic to scrape gaskets off aluminum parts. But I have used a piece of copper tubing, flattened at one end and ground to an angle, then cleaned up with a wire wheel. It doesn't seem to hurt the aluminum at all.

DOC;
I have heard of guys (although I haven't tried any of this) taking a piece of old speedometer cable slightly longer than the passageway to be cleaned, chucking it up in a variable speed drill and slowly "drilling" the passageway open. Once you get it iopen you could use a combination of "drilling", "picking" and perhaps Seafoam to dissolve the crud.

Dremel makes a flexible shaft for their moto-tool. I wonder how tight a radius it will do. If it gets tight enough, this and a wire wheel attachment might work.

I was wondering if a soft copper wire (like electrical house wire with insulation
removed) would work.

Those angles and curves - Lord! You can't get any force thru that....

Maybe a very long spring, like used in sewer pipes, but very small.

I have an air compressor, so that would help, but not everyone reading this has
one!

I hope that someone reading this has come up with a good method.

What do mechanics do when someone brings a car in for an overhaul ?
Buy a new Intake Manifold?

I just thought of something....If I can get an opening enough to pass air,
then I can use an air-gun sandblaster to cut thru that Carbon!
Shooting grit thru the passage would scour it clean....

DoctorBill

Just had the thought pop into my head: How about a cleaning brush like those used on a brass band instrument? They have very flexible shafts...

Useing a piece of speedo cable works to clear the passages. It may take more than one length to work from each end and a longer length to go all the way through. Hi-pressure water washer like at the carwash will wash it clean once it can spray through. Does the EGR flow into the plenum or through the small holes near each intake port?

Yes, more than likely repair shops would buy a new manifold.

I just rechecked my Intake Manifold with a wire-tie (for Garbage Bags) and it
wasn't as bad as I thought. Hard to see something jet black and unreflective!

I may have less of a cleanout problem than I thought.

Question - this Carbon comes from the exhaust. Are all 3 cyl Metro EGR ports
carbon plugged? Is this a normal problem or will it clear out once the
engine is running properly?

I would suspect that once Carbon is in those particular EGR passageways, there
is nothing to clean them out after that.

Should one take the EGR off and run a ream thru there on an annual basis?

Seems like bad designing to me.

Raining today - cold wind. Did nothing.

DoctorBill

There are better designs. I unplugged an intake on a Honda Accord in the car. Removing and cleaning would have been faster and easier. Intake manifolds on GM 292's will completely block the intake. It is better not to plan any EGR passage maintenance. EGR carbon can break off and get on top of pistons without any help and cause rod knock. Oil in the exhaust will make more carbon. Your EGR will likely stay clear for a long time while the engine is running well.

This worked for me (pics)

http://www.teamswift.net/viewtopic.php?t=26138&highlight=egr+brush

That extra long "Tubing Brush" would work well if it were flexible enough....

I was told by a mechanic at the Head Shop where I had my Head Rebuild that
getting all the carbon out is critical.

He said that this engine's valve return springs are little poopers and are not
very strong.

Consequently, if a flake of carbon breaks off and starts to go thru the exhaust
valve and has the valve close on it, then the flake gets smashed in the valve
seat and stops the valve from closing all the way. It can stay there for a
long time and cause the valve to burn up as the exhaust gases are not
stopped - the valve is, in essence, always open....

Sounds reasonable to me.....

So I am making it a religious thing (The Carbon Crusades) to get all the evil
Carbon off of the Piston tops and Ring Slots and out of the EGR system since
those particles can wind up in the Intake Input to the cylinders.

This is how much came out of just the EGR Valve alone from a spare that
I bought at a local "Pull-n-Save" a while back...from a previous thread.
http://img98.imageshack.us/img98/9437/tbcleanupaa1ie.jpg
http://img80.imageshack.us/img80/3839/intakemanifoldtopviewadded9hd.jpg

DoctorBill

I think I found it - by Jove!

You know, if you fumble around in a haze long enough, you stumble over the
very thing you need! You just need to see it!

As I was rummaging thru my tools (which I keep in fastidious order!), I picked
up something that is always 'in the way' and bugs me....

http://img377.imageshack.us/img377/263/mytoolsgarageak6.jpg

I looked at it and an idea struck me!

The perfect tool to clean out the Intake Manifold's EGR passageway of Carbon!

http://img61.imageshack.us/img61/6052/ideamagspringcleanerkh2.jpg

These things are a dime a dozen in any hardware store, Sears, K-Mart, Harbor-Freight.

I got one for $1.50 a while back. Almost never use it, but when I need it, it
pays for itself 10x over!

If I cut off the Magnet from the end and fold a loop over on itself with long
nose pliers, it should work thru the Carbon, but not scratch the Alunimum in
the IM's EGR passageway....

It even has a nice red handle to turn it with!

*******This was added several hours later by Editing...

I tried the spring on my Pull-n-Save Intake Manifold.... Worked, but a bit too stiff.

http://img223.imageshack.us/img223/7341/magspringtryoutvg2.jpg

I will keep my eye out for a less stiff spring - needs be only about 8 inches long!

DoctorBill

PS - I know exactly where every tool is in my Garage....contrary to what my wife believes!

Hey, how about this:
Take a small mini-torch to a pile of this carbon that you've scraped out. If I'm not mistaken, it will ignite. So why not stick one of these mini-torches into the passage and just let it burn out the carbon? Soot in Diesel particulate filters ignites at 600 or 650 centigrade. I don't think this soot is much different; mainly C with some H mixed in...

You know what might work? A small plumbing snake. It's a flexible spring like the pickup tool, but might be less stiff since it has to curl through plumbing. Heck, it's job is to clear out clogs - be it carbon or crapola, it's still a clog. The only question would be, do they make one small enough?

Small plumbing snake? Maybe that would be like a piece of choke cable housing turned with a drill motor.

try this:

a steamer & air compressor blasting combo!!!

steam vapor would soak into the carbon, then blast it w/ air to "push it out"--> i mean lookit that gray compressor w/ the blue hose just sitting there on the side... geez!

same principle as those other people using water to clear out carbon deposits from the combustion chambers...

I believe I have found a way to periodically clean out the Carbon from
the EGR passageways without taking the Intake Manifold off the Head!


I found a spring that works quite well for doing this! In a drawer in a Hardware store
for $2 each!

It is 4.5 inches long - 1/4 inch in diameter and quite flexible with loops at both
ends like an old screen door spring.

http://img231.imageshack.us/img231/8535/newspring1gp5.jpg

I expanded it out with my hands by pulling it to extend the spring out to 10
inches.

I whittled the end of a wood stick like a pencil, screwed it into one end and
glued the stick into it so that it can be held to "drill into" the Intake Manifold's
EGR passages.

http://img232.imageshack.us/img232/6405/newspring2td8.jpg

It is so flexible yet strong enough to "snake" into the passages and scrape out
the Carbon...

http://img61.imageshack.us/img61/678/newspring3bj0.jpg

Remove the EGR Valve by loosening the two bolts holding it on. You will
need to either buy or make a gasket. Gasket material is cheap!

Now - if you wrap a piece of masking tape around the spring at exactly 5 inches
from the end and 'snake' it into (push hard while twisting the wood hande)
the hole shown in the picture, the spring goes to exactly the end of the
passageway to the Head. If you want to go further into the Head, I
did not measure that. I measured the two I mention here....

Twist it a while to loosen the Carbon. Pull the spring out and put the hose
of a Vacuum Cleaner up to the hole. That will suck out the Carbon and keep
it from going back into the Head.

Then - place a new piece of masking tape on the spring tool at 6.5 inches from
the end.

Snake this into the hole going back toward the back end of the Intake Manifold
to the Throttle Body. Twist it a while and pull it out. Suck the Carbon out
with the Vacuum cleaner! This last is critical as you don't want loose Carbon
being sucked into the engine and screwing up your valves!

BAM! Clean passageways w/o removing the IM....!

Now clean the EGR Valve with dental picks (buy those at Harbor-Freight...?)
and you can put the EGR Valve back on with your new homemade or purchased
gasket.

This should make many a Geo Metro run more efficiently!

No having to remove the Manifold to do it either!

DoctorBill

This tool may work better for cleaning IM passageways. It is a trumpet bore snake. The brush is nylon. A wire brush (brass) might be better, but you don't clean brass instruments with brass brushes.

http://www.wwbw.com/Micro-Trumpet-Cornet-Cleaning-Snake-472392-i1420875.wwbw?source=TWBZWXX

They make bore snakes for rifle barrels that have brass brushes at the end. But the snake part is like a rope with a brass weight on it. So you drop the weight in the barrel from the breach end and pull the brush through (one direction only, so you couldn't push & pull to scrub like you can with the trumpet brush).

Doc, what I've had the best luck with is about a 1ft. long piece of coiled cable jacket. (this is the stuff your lawn mower throttle cable runs through). If you cut it right & "drill" through the carbon using light pressure & your fingers to turn it, you'll make a nice hole all the way through the carbon.(carbon dust will flow out through the jacket...when it plugs up, just whack it against something hard)(NOT your windshield). After you have this "pilot" hole through the junk, do like the others are saying with the speedo cable & a drill...should clean up real nice. If anything's left after that, (look close with a good flashlight) use your dental picks. Now, the EGR passages will work just fine even if they're not perfectly clean, but the cleaner you get them, the longer they'll stay that way. GL...

Hey folks
I just cleaned out my EGR passages when replacing my cylinder head.
I found a passage that some of you may be overlooking, and I think it's important.
It's on top of the EGR valve. I thought it was a vacuum port because it is small with a rubber hose going up to the EGR modulator. From my Haynes manual (yeah I know) schematic, I saw that it is actually an outlet for exhaust gas pressure (not vacuum) to go to the modulator. Anyway, I noticed that it was completely blocked. I dug with a wire, I soaked it, etc. I didn't want to break something inside the valve, but from the schematic it looked like it just went to the chamber on the exhaust mfld side of the EGR valve. So I took a small drill bit and drilled it, because I could not blow air through it at all. I finally broke through the rock-hard carbon and could blow air through it. My modulator was getting zero exhaust pressure through the hose because of this! That would cause the modulator to think that EGR was not flowing, even when it was! So I think I was flowing way more EGR than I should have with this small port blocked.
Please check this port on top of the EGR valve. It needs to be open to exhaust flow.

Thank you SchlochRod, I cleaned my EGR value and path ways several times with out any luck keeping the check engine light from coming on, read your post and sure enough I had missed this , drilled out the tube in the EGR and now 3 days no check engine light after resetting ECM and engine runs smoother. Thanks again!!

Why bother? My car wasn't even built with an EGR. Just one more thing to go wrong:biggrin:

I have found that if you take it to a local machine shop or repair shop, they can put it in a tank and soak it loose for you.
It's a fair bit more expensive than doing it yourself of course, but they have an acid based dip that won't hurt aluminum and it worked great for me on mine. I don't think that mine was plugged like that tho.

Hopefully, this brief response reference will be helpful for anyone having egr system fault codes. Please take a look at my post of a couple days ago on this exact subject. DoctorBill has (or had) a 1993 Geo Metro. His car, according to my observations of his well documented photos, has the Standard Emissions system installed. My 1994 base model Geo Metro has the Upgraded Emissions system. I only mention this because, the bottom part of the throttle body injection unit differs between the two systems. The plenum design of the intake manifold also differs. Just keep this in mind when you read my referenced post: http://www.automotiveforums.com/vbulletin/showthread.php?t=1075458

Doctor Bill, among others in this fine forum, is really professional in putting together his posts. It is not my intent to do other than to state that the procedure that worked for me has evolved from more than a year of failed partial solutions.

Hope you all have a great and productive day!

Respectfully,

MetroKinsman

I think you guys missed it about 13 posts ago from a guy in nowhere else but Mechanicsville,Va.
DOC;
"I have heard of guys (although I haven't tried any of this) taking a piece of old speedometer cable slightly longer than the passageway to be cleaned, chucking it up in a variable speed drill and slowly "drilling" the passageway open. Once you get it open you could use a combination of "drilling", "picking" and perhaps Seafoam to dissolve the crud".
Speedo cable is very flexible. I doubt the inside finish of the passage has to be perfect,(polished) and the variable speed drill makes it controlable. I've no experience with Seafoam products but I'm sure carb cleaner will be more agressive. Cut the cable with a pair of side cutters to give ya a chiseled end and renew the end from time to time. This is by far as the fastest method I can think of. Heating it is out of the question. If it were cast iron or even steel it would work but the temps needed to get that carbon cherry red might warp the flanges.

Aside from preventative maintenance, here's another idea to try. It might not be the best idea, but I wonder how it would work. Back when I used to cook for a living, gas stove arms would get clogged up with carbon. All the burnt food would get down into the little holes where the gas was supposed to come out as flame. One way to clean it out was to get it real hot and dip one end into a bucket of water (perhaps with a little vinegar). The other end with the holes sticking out of the water would emit steam like crazy and unplug the holes. Maybe one could try something similar in this case?