Bottom Half of Throttle Body Exposed !

I went to "Pull-n-Save" and obtained the bottom half of a 1993 Geo Metro
1.0 L - 3 cylinder Throttle Body which I did not take when I got the Top Half
a couple of weeks ago.

I have removed all the hoses and the bracket holding the Throttle cable.

Here is a photo of one side. (right facing engine):

http://img494.imageshack.us/img494/2376/bottomtbnamedpartsshown3qa.jpg

This is the opposite side (left facing engine):

http://img397.imageshack.us/img397/8033/bottomtb6otherside4qy.jpg

Several things I noticed.

1. The larger forward input port to the EGR Valve was totally plugged up with crap!
.....I will now take the hose off of mine and check this out....!

2. There is a 'mechanical' throttle lever stop adjustment that I did
not see before and which The Chilton Manual does not mention....!
Notice the arrow pointing to it. This IS NOT the "Idle Adjust Screw..."

3. What is the port where I have shown a red arrow? On this TB Top Half,
that port had a rubber cap on it! I will see if mine has the same cap.
There are two ports one on top of the other. The bottom one was capped.

4. I want to remove the two nuts holding the TB Top onto the Intake
Manifold and see how the Air Control Valve works.
Those two are at the bottom of the ACV. More to come....

This was instructive in that I now know that the EGR Valve may be plugged
on my TB Top and that I CAN ADJUST the Throttle Stop via that mechanical
stop just as one would a lawn mower engine!

DoctorBill

if its plugged at egr valve chances are the passage though the head is plugged too

"if its plugged at egr valve chances are the passage though the head is plugged too"

Well, you were right! I unbolted the EGR Valve and here is what I found:

http://img71.imageshack.us/img71/8174/pluggedegrvalve34bf.jpg

That is Carbon - solid Carbon in there as if someone had poured black cement
thru the EGR and Intake Manifold!

Is any of this salvagable?

Can this stuff be cleaned out of an EGR Valve...?!

I now have even more things to check out on my engine out in the driveway
when the weather breaks!

DoctorBill

the passage i was talking about you have to pull intake manifold or exhaust to see, its the passage going from the exhaust manifold through the head to the egr valve

I keep learning.....

I neglected to mention that the TB Bottom Half I obtained was connected to
the Intake Manifold.

So, therefore, when I read your last reply, I immediately looked closer at the
whole thing and discovered the port at the lower right side of the Intake
Manifold that goes from the exhaust (??) to the EGR Valve.

This port, as you can see in the photo, is also totally occluded with carbon.

I thought I understood this device..... What is that port on the Intake
Manifold? Is that exhaust going into it?

http://img74.imageshack.us/img74/3432/pluggedegrmanifoldport6mo.jpg

Perhaps someone might explain what that little port is for and why it is full of
carbon.....Please!

Second - how does one clean this mess up?

What is such an occlusion doing to the cars performance?

If my EGR Valve - the one on my Metro - is like this, what do I do about it?

What is this a symptom of...?

Oh - and by the way - which direction is this stuff going?
From the Intake Manifold to the EGR or from the EGR to the Intake Manifold?

What is the source of the Carbon crap? This can't be NORMAL!

HELP! I don't understand - and I hate being ignorant...!

DoctorBill

egr stands for exhaust gas recirculation, it takes exhaust gas out of the exhaust manifold, passes it though the head to intake side and at certain times the valve opens up and put that gas back through the engine. the carbon buildup is from unburned fuel and oil

You have explained what EGR means... Why is this done anyway?!

Is this much Carbon buildup (which is not a natural product of combustion...)
normal to find in the Intake Manifold?

BTW - "Normal" combustion with sufficient Oxygen produces ONLY carbon
dioxide and water as when butane is burned in a torch and makes a nice
blue flame.
Carbon is a sign of incomplete combustion - poor air supply.
Also carbon monoxide is a sign of poor air supply.
There is NO SMOKE when a flame is fed enough Oxygen......
Unless the fuel has something which cannot vaporize mixed in it like the
solid fuel in the Shuttle Booster which has granular Aluminum as part
of the solid fuel and produces the voluminous white Aluminum Oxide clouds
of 'smoke' one sees on takeoff.
The Shuttle itself makes a nice blue flame with absolutely no smoke.....

I is being a Chemist by trade, so I know about flames and combustion
(which are 'plasma', BTW - the 4th State of Matter)

I know engines produce smoke when accelerating (bad air mixture), but is
what I found in this TB "Normal"?

Whoever owned the Metro I got this TB and Intake Manifold from at the
P-n-S must have had a smoking, poor mileage, coughing automobile.......

Three BIGGIE questions (Biggie Size it for me!)

A. Is it likely I will find this much Carbon Buildup in MY engine? 150,000 miles

B. How does one clean this mess up or is it possible to do so?

C. Is this EGR Valve toast, wiped out, roadkill, a gonner, dead meat, etc?

Thanks for your comments, guys.....

DoctorBill

Have you got something against Monkeys!

Hey! Monkeys got rights!

Back to reality - I know why engines "coke up".
And petrol will also burn 'clean' with enough Oxygen.

Racecars use Nitrous Oxide for quick power just to get
enough Oxygen in there when the power is needed but
probably burns up the engine also. Iron burns in Oxygen....
MOST things do - Astronauts in space capsules at NASA....

Acceleration boosts raw power, but burns quite inefficiently
making carbon particles. My MAP supposedly being dead
probably made my system carbon up.

That's what I am concerned about.

But....no one has answered as to how one cleans up the EGR if
it is 'coked up' as this one was. I presume you throw it out and
buy a new one.

OK - but what about those passageways in the Manifold?

Use a dental pick?

I will soon look at the EGR tube in my Metro outside to see if it
is plugged as was the one from P-n-S.
If so, then I guess I should take off the Intake Manifold (IM) to look
for 'Coking Up' as this unit has.

And again - then what...!? Get a new IM.

What's with the Monkey? You no likie?
I will find something new and amusing soon.....

DoctorBill

I have a question here: Is the Lower TB integrated with the Intake Manifold? No way to separate the two? Because I have a 92 TB/Intake combo with an EGR that I wanted to put on my 91 (which has NO
EGR). If it's one piece I guess that I could use a block off plate for the EGR port, don't you think?

I love the pics and all of this analysis, keep it up!

This is an addendum to my post of 12:12 PM today......

If that 'Coking Up' (nice term...) goes all the way thru the Intake
Module (IM), then it must, obviously, go all the way back thru the
Engine Block to where ever it started from...

And I bet it goes all the way into the Air Control Valve
(ACV) since that has a passageway from the EGR to it!

If the Engine Block is Coked Up, I would suppose that such
a situation means a ruined engine block...no?

Once someone tells us how to clean this crap out (if one CAN do so!),
then we'll all be relieved...

If no one knows how to remove all this 'Coke', then perhaps some
of us are screwed!

In either case, such a Coked Up system seems really, really bad....

I would bet that the car I got this set-up from was a "City Driven"
car.

My Metro has been driven at 60 mph for most of the mileage that
I put on it (8,000 miles) after I bought it from a Montana dude.
They drive over there like all Hell is breaking loose (I am told...).

So I hope mine is not like the one I got from P-n-S.

Tomorrow, I'll have time from grading papers to go out and have a look.

DoctorBill

Go back to my post on 1-22 at 1:20 PM.

You will see that the bottom half of the TB is bolted to the Intake
Manifold (IM). So perhaps you could accomplish what you want (?)

DoctorBill An "old' conservative prick.......

Thanks Dr. Bill. I thought that I saw a couple bolts on there but wasn't sure.

Hey nothing personal meant to you about my sig, I just hope that an intelligent gentleman such as yourself isn't fooled by these current crooks in the White House.

Every day some other crap comes to the surface about those bottom-feeders and their subsidiaries. I despise Neo-conservatives and their corrupt money-grabbing agenda for the rich and their bleeding of our fine warriors in this stupid illegal war.

Support the troops, not their civilian leadership is what I say and that includes giving them clean water.

Don't drink the Neo-Con Kool-Aid!

Now back to our regularly scheduled Metro forum.

Hey guys,
The carbon buildup is a real pain to remove. The easiest way that I have found is to 'hot tank' the parts invovlved. The EGR valve is salvageable if the diaphragm is not torn. I use Gunk carburetor cleaner for the EGR and a modifies shotgun cleaning kit for the passages in the head and manifolds. The only problem is the intake ... do not push that crap into the intake passages or things will go bad quickly. Dr. Bill, take that old intake to the local engine rebuilder and ask him if he will throw it in with the next set of heads or engine block to be 'hot tanked' I am betting that it will be clean as a whistle if he will. On the manifold passages and the head, use some patience, this material is only aluminum... but my method of carb cleaner and Hoppes #9 shotgun cleaner seems to work fairly well.
Hope this helps!
P.S. I am a conservative prick too! Keep the politics at home !!

I now understand what and why an EGR Valve is about.

Do they get very hot...?

The one I took off the P-n-S TB & IM is Coked Up and I will
try to clean it out as "practice" for the one inside my Metro
out in the driveway.....

Please describe what is inside the EGR.

Here is Chilton's Diagram for Carbureted Engines
(hope I'm not infringing on Copyrights)
http://img71.imageshack.us/img71/4281/egrvcarbd7wf.jpg
and Fuel Injected Engines (Mine)
http://img71.imageshack.us/img71/9730/egrvinjectd0nw.jpg

Is the EGR Valve actually the same for both Injected and Carb'ed?

Does it have any RUBBER in it that would be Ruined by solvent cleaners...?

AND - AND - does the EGR Modulator pass hot gas THRU it?
i.e. will THAT need cleaning out also?

DoctorBill

Now that picture was worth it! Love it!

Gives meaning to "LOL"...!

So I had better not soak the EGRV in Gasoline or some chlorinated
hydrocarbon solvent, or I'll destroy the EGRV.

Well. I'm off to lecture my Chem students on Radioactivity
(alpha, beta and gamma), the four forces of nature (gravity,
electromagnetism, strong and weak force), Fission and
Fusion, and nuclear decay mechanisms with decay equations,
and half-life.

Lot of fun..... Really! More fun than 22 years of working in industry
as a lab research scientist for Bayer Corporation.

As Ahnold would say - "Ahhlll be baaak....." later Dudes!

DoctorBill

I went to Harbor Freight Tools and bought a set of various picks to
clean the EGRV and IM passageways Carbon Deposit out.

I found it to be quite soft, but a bastard (messy) to clean out
because it is completely black and non-reflective. The stuff is
essentially "Lampblack" - that carbon that collects when you
put a metal object into a candle flame - used to be used for
making India Ink...
It is quite hard to see what you are doing via a normal incandesant lamp.

I should be out in the summer sun doing this - the carbon black
gets all over the place! Can't wait for summer.....

I think a soft copper wire would allow one to 'ream out' the IM
passageways. It would push thru the carbon but also follow the
curves w/o scratching the Aluminum very much. A copper wire
of the size used in house wiring would be perfect - maybe with
the end bent into some kind of rounded hook or helical shape...

Just thought I'd let folks know what I found....

DoctorBill

I have a question about that air valve assembly that screws into the bottom of the Throttle Body on DoctorBill's car. How tight is the retaining cap supposed to be? When I tore mine down a while back, I noticed that it wasn't seated all the way. Is there a certain spot for that cap to be screwed down to?

I'm also needing to replace parts in my EVAP canister. The diaphram is torn. Is there anyway to obtain new parts? I figured I would get one from a U-Pull-it Wrecking yard, but I would be willing to purchase one from someone here if someone has one.

Alright! The oddyssey of the "Old Conservative Prique" continues.....

I tore the entire Intake Manifold - Throttle Body Lower Half -
EGR Valve unit apart.

I couldn't believe it, but I got most all of the Carbon Crap out of
the system.

The erstwhile 'Coked Up' and filthy EGR Valve is emminently cleanable!

I wailed into it with my trusty set of picks from Harbor Freight Tools ($3)
and dug out almost all of the carbon from the two ports clear down to
the moving valve doohikie on the flat diaphragm side. I then used a
couple of drill bits (smallest first) and drilled the carbon out of the tube
which I first saw plugged up. That was drilled out by holding the bit in
my fingers and gently turning and pushing it in. Went all the way in
about 1.25 inch until I hit open space. Then I went up in drill size and did
that again, etc etc until the tube was cleaned out. No sweat...!

I even put a tube on the Vacuum port of the diaphragm and sucked on it
to see if the valve stem visible in one of the ports would move - IT DID!
I will get my Air Compressor working later and blow the rest of the carbon
out of the EGR Valve. $100 worth of valve (NAPA price new) recovered......

That done I wailed on the Intake Manifold. Not done cleaning it yet.
Here is what it all looks like right now:
http://img98.imageshack.us/img98/9437/tbcleanupaa1ie.jpg

I then used a socket wrench and removed the two nuts holding the
Air Control Valve - lower Throttle Body unit onto the Intake Manifold.

Here is what the Intake Manifold looks like (two views) - the pile of Carbon
came mostly out of the EGR Valve:

http://img96.imageshack.us/img96/6107/intakemanifoldsideview9cm.jpg

http://img80.imageshack.us/img80/3839/intakemanifoldtopviewadded9hd.jpg

The exhaust gasses (red arrows) go thru a tube within the IM and come out a port
inside the IM underneath that shelf - way underneath clear over on the right inside.
If you insert your finger, you can feel the port opening clear over on the righthand
inside - under the ACV port. Dirty fingers result....

The Bottom Half of the Throttle Body looks as follows (3 views):

http://img100.imageshack.us/img100/9658/tbbottombotview12fz.jpg

http://img54.imageshack.us/img54/5904/tbbottombotview2corrtd1nu.jpg

http://img68.imageshack.us/img68/4083/tbbottomtopviewcorrtd3qf.jpg

I think I understand this beastie now.....

Now - if I have anything wrong on these photos, Please tell me so I can correct them!

I am tired now - it is 11:50 PM, I just graded 50 Chemistry Quizzes, took
these photos, labeled them up in PhotoShop LE, Loaded them into
ImageShack.us, wrote this, and I am ready for night night.

I hope some of you folk find this instructive. I sure as Hell have learned
a lot about my Metro.

My conclusion from this particular senario is that one can CLEAN UP one's
EGR Valve and Intake Manifold of all the Carbon Crap Buildup. It is possible.

Now I would have to cut out several gaskets to reassemble the goodie were
I to use this setup on my Metro.

DoctorBill

OK, Blake - I corrected the photos. Please check them out.

I am still trying to follow what you wrote - especially about the VSV
(Vacuum Solenoid Valve ???).

If you look at the second TB Bottom Half (TBBH) picture - does the VSV connect to
one of those tubes at the top just above the ACV opening on the right side
of the TB bottom half? One is capped off!

There is a small tube sticking out of the back half of this part which
did not show up in the photos. It seems to port into the ACV hole at about
5 oclock on my second picture of the TBBH. What is that for?

No Wait! Yes, it is showing in the first photograph! Sticking out at an angle
form the TBBH at about 11 oclock of the EGR Valve housing.

Then on the direct opposite side of the TBBH are two tubes sticking out
side by side - purpose?

I suppose I should take another photo to show all those tubes....

BTW - click on the thumbnail of the Fuel Injected Metro Emission diagram.

http://img95.imageshack.us/img95/9495/emmisionfuelinjected899317mr.th.jpg (http://img95.imageshack.us/my.php?image=emmisionfuelinjected899317mr.jpg)

DoctorBill

Was gibt, mein Herr !?

Haben Sie nicht eine kleine antwort ?

Have you reached your limit on answering my endless questions?

You do realise that they are endless, don't you?

That is because there is a total vacuum in my head which requires endless
filling with information.......

Resistance is futile! We are the Borg!

You will be assimilated into the collective.....

DoctorBill

Hallo,

Go ahead with the better pics and pointers and I will be happy to answer this post.

Tschuss,
Blake

That's what I did !

Go back to the original posting...... I simply Edited the pictures.

Replaced them, as it were.

They's all better, Man..... I done fixed them. Long time 'go! That same day...

DoctorBill

I am bumping this thread up. There are some awesome pictures here. Thanks docorbill!!

I do have a question about the air control valve as pictured above. When the engine is cold the valve is open to aid in starting and bumping up the idle and closes as the engine warms.

When the engine is HOT should the valve be completely closed? So that NO air enters thru the that top hole pictured above by doctorbill??

So when hot, If i put my finger over that hole, it should make no difference in idle since the valve is closed below.

Thanks for any input

i hate to tell you after all this work but what you could have done was just replace the manifold with a non egr one. the cross head passage then goes to nothing so doesn't matter if its plugged or not. you ever get your car running?

No....

I have been using my Jeep Cherokee 4 L. 4wd since last Fall.
23 mpg....!

I am a lazy, no good for nothing SOB......

For some reason, I have lost interest in fixing that little bugger.

BUT - today I had to buy gas at $3.02 / gallon.

Jesus H. !

So.....if I can just get off my dead butt and install the TPS , the Throttle Body,
hook up the hoses, test the compression and fuel pressure - I might get it working.

Even at 30 mpg, it would save me gas over 23 mpg on the Jeep.

DoctorBill

Someone said to me that dinosaur fossil bones
were put there as a test of Faith by GOD.
Do some folks actually think GOD would be so perverse
as to con us scientifically and then screw us if we fell for it !?
Think of the implications of that actually being true.....
God help us all !