Bottom Half of Throttle Body Exposed !

[DOCTORBILL]

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):



This is the opposite side (left facing engine):



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

[Crvett69]

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

[DOCTORBILL]

"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:



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

[Crvett69]

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

[DOCTORBILL]

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?



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

[Crvett69]

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

[DOCTORBILL]

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

[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

[theragtopguy]

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!

[DOCTORBILL]

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

[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.......

[theragtopguy]

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.

[mik13usa]

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 !!

[DOCTORBILL]

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)

and Fuel Injected Engines (Mine)


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

[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