rev up your engines today I'm gonna talk about an illegal modification that
people used to do all the time on cars make them run better and that has to do
with removing the EGR valve now on my matrix here it doesn't have an EGR valve
but I didn't remove it illegally it didn't have one in the first place cuz
it's a more advanced design know each our valves are anti-pollution devices
stands for exhaust gas recirculation valve when they first put catalytic
converters on cars when they put the catalytic converters to burn pollutants
what happened was they got too hot because as they burned the pollutants
sometimes they'd get red-hot burning the unburned hydrocarbons and things just
got too hot so engineers started scrambling how can we make the
combustion temperature get lower well they did it by reducing the amount of
oxygen going into the engine realize that if you add an inert gas into the
combustion chamber then it can't burn as well and it won't get us hot now they
could have done something like put a canister nitrogen that's an inert gas
and have that add it to the engine of course that would have to be refilled
you know Americans weren't gonna be refilling up so they came up with this
bizarro compromise the EGR valve this bolts of the exhaust the EGR valve takes
exhaust gas and the old ones like this used the vacuum valve that would open it
up when it was needed and the exhaust gas was then routed into the engine now
you might think why the heck would you put exhaust gas into your engine it's
the stuff coming out well exhaust gas is already burnt gas it's
mainly inert so it sounds weird but it's true
but adding this somewhat hot exhaust gas into the engine actually made it burn at a
lower temperature even though it was a warm gas it didn't have oxygen in it
well a tiny bit oxygen but mostly oxygen was gone so it was more or less than
inert gas so when it went inside the engine
it made the temperatures go low so the catalytic
converters didn't overheat when I was young mechanic we see those babies glow
and cherry-red not a cases so Toyota here's the EGR tube right here you see
that tube that tube comes from the exhaust and goes up connects to the EGR
valve here when the engine computer decides that it needs to send some
exhaust gas to the engine to cool it down it opens up an exhaust gas goes
into the intake and it's sucked inside the engine and that reduced the
temperature inside the engine so it didn't create oxides of nitrogen which
is a deadly pollution for humans got rid of leaded gasoline because the lead
pollutes and hurts people catalytic converters originally they're supposed
to burn unburned hydrocarbons that are bad for you but they were burning so hot
they were creating these oxides of nitrogen that created a different type
of pollution so they traded one pollution for another with the first
catalytic converter system so these old-fashioned simple EGR valves kept
them from creating all these oxides of nitrogen it was adding an inert gas
which made the combustion temperature get lower so the catalytic converters
wouldn't get hot enough inside to create these oxides of nitrogen all in good
from a theoretical standpoint but I'm sure you realize I'm gonna tell you in
the practical world things work differently
the original EGR valves were somewhat fallible they broke down a lot the
rubber would rip because it's got a rubber diaphragm while hey all that heat
is gonna destroy the diaphragm right and the tiny little holes inside they would
get carbon in them and sometimes they were jammed wide open if they jammed
wide open then the exhaust gas was going in the engine all the time it would run
really poorly and then here again they would create more and different types of
pollution cuz the engine wasn't running you're right back in a day I guy would make
their own fix to take the EGR valve off and there's a gasket here they would
just make a solid aluminum gasket bolted over the hole so the EGR valve wasn't
connected anymore and that was the end of any problems with the EGR system now
the vehicle would run better that but of course it would also pollute more
in a day nobody checked the pollution there weren't inspection stations every
year where you went in to get the pollution system tested to see how much
your car polluted none of that even existent so guys would just block them
up and drive on their merry way now if you wanted to check these old ones they
were pretty simple you put a vacuum gauge on here and you give it vacuum and
if it lost vacuum and fell down and didn't stay up the diaphragm was ripped
in you have to buy new one and another simple test was to just take the hose
off put a vacuum gauge on here stock the car then when you gave it vacuum it
would open if it opened the car would start to stumble at idle and then when
you took the hose off and it stops tumbling you know the thing was working
up and down but as I said since some of the after-effects of burning gasoline is
carbon the carbon cut off and carbon up these valves and they would stick so you
could physically take them off you saw carbon you could spray them with really
good cleaner carburetor cleaner already used in those days there's better
cleaners today but we use carburetor cleaner you got the chunks off it would
work again and the GM ones are so bad and so notorious that they actually put
a screen over this little hole here so that the carbon pieces couldn't get it
inside because they were so poorly made the engines and the whole car as a
matter of fact that when chunks of carbon would break off and they often
did they clog the valve up so they put a screen in there to try to prevent that
of course there was a stopgap measure cuz if enough pieces broke off they just
clogged the screen and then it wouldn't work right either and speaking a nutty
designs GM later had electric solenoid EGR valves that had three electric
solenoids that would work to open and close EGR valve by computer control and
those systems were always breaking some of those valves are 300 something bucks
apiece and since they do bolt onto the exhaust part of the engine so exhaust
can come through all that heat and then cold in the winter and then heat when
the engine heated up they would often rust on solid making it almost
impossible to get them off a lot of them were like this Toyota where they had two
EGR pipe that screwed on in a pipe invariably would rot away or when you
tried to change it the nut would be rusted on solid when you pulled it would
just break off in your hands so it could be a real pain in the butt changing
these things out on an old car I'm happy my Toyota here doesn't have an EGR valve
but I didn't break the law taking it off they didn't build them with EGR valve so
was toyota polluting more now actually they're polluting less because
it's a completely different design it doesn't use EGR valves in the first
place as you can see this says VVT - i 16 valve and what that means is that
this Toyota engine has a variable valve timing system that system is all
computer run that the cars no longer need EGR valves to stop the pollution
from being created they don't create oxides of nitrogen by the design of the
valve system since a straight cam with no variable valve timing has one cam
setting and that's it at certain speeds it would pollute more so to stop that
heat and pollution on with the EGR valve but take a modern variable valve timing
engine it has timing that can vary the computer can set it for different
situations so it does not create the heat in the combustion chamber that
requires an EGR valve to stop oxides of nitrogen from being created the
catalytic converter and yeah it's super high-tech technology there's no arguing
that but you take a vehicle like this
Toyota they make such good variable valve timing really have a problem take
engines like Nissan and BMW as they age there are notorious for having variable
valve timing problems and if you think it's something to buy a $300 EGR valve
that some of these Chevy's had when they went to the electronic EGR valves where
do you see what it costs to fix a VVT system and a Nissan you can spend
thousands on that which is yet another reason why you want to change your oil
regularly in a modern car you don't have problems with a variable valve timing
system and you know I was cheap variable valve designs are very expensive defects
and of course it's also a reason you want to pick the right car in a first
place because if you see a manufacturers have problems with the variable valve
timing systems in any other engines do not buy one of those cars because of
pollution control government regulations it's never gonna go to the Past from
cars who are simple and easy and cheap to fix gonna buy a modern car it's gonna
add variable though just make sure you pick one that has a
solid reliable system not one that breaks down too early high technology
it's great when it works but it isn't when it breaks so you want to buy high
technology that has high reliability just really make sure that when you buy
a car these days of course you can be like me and drive a lower technology car
now that things still fuel-injected but it has an infinitely lower level of
technology than any modern car 26 years old so now you know all about the lowly
EGR valve how it came into being I know now it's pretty much gone extinct now if
you have a modern car with variable valve timing you'll pretty much be
wasting your time trying to find where it is
because the engines don't even have one item anymore, so if you never want to
miss another one of my new car repair videos, remember to ring that Bell