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Tiguan direct injection valve cleaning
At 64,000 mile i had my engine valves manually cleaned ($800) as the check engine light came on and the dealer said the new direct injection engines have issues with the valves getting covered and not seating right since the gas goes into the cylinder versus past the valve to keep them clean.
After 20,000 it started again on cylinder 4 after i let it idle on a cold morning ( random missfire) cylinder 4.
Theres a new solution VW has to put in the gas and drive 100 miles in sport mode, doing this twice.
Has anyone else done this and had success, this AM the car studdered bad and the EPC light came on. After indrove a mile i stopped and restarted the car and it seeems fine.
Re: Tiguan direct injection valve cleaning
I have never, EVER taken a car in to have anything in the engine manually cleaned, AND
it is not necessary. I have 230,000 miles on my TDI, and never had to do that. This is
the first time I have ever heard of this, personally.
Putting in a bottle of Marvel Mystery Oil every 3rd tank is what I have always done,
and before every 3rd oil change put half of it in the crank-case. There is no reason
to pay anyone $800.00 to clean valves.
You can also use the Seafoam that comes with a hose that gets clamped under
the intake tube to the throttle-body. Have someone rev the engine to 2000,
and you empty the can into the motor. There is video proof that it works.
The explanation in more depth to what you were told:
There are three reasons why direct injection engines are more prone to carbon deposits. One reason
is unique to direct injection, and the remaining two are problems for port fuel injection engines too,
but are made worse by direct injection. If you look up direct injection carbon deposit problems on
the Internet, engines from BMW, Audi and VW always rank the highest. Engines from GM and Ford
that have been on the road for at least four years hardly have a carbon deposit complaint. Some
direct injection engines have bad timing. The modern engine typically has variable valve timing and
even cylinder deactivation. The engine management system can control when, how long and, in
some cases, how deep the valve goes into the combustion chamber. If an intake valve is dropping
into a combustion chamber with combustion byproducts or unburned fuel, the valve might be
exposed to the precursors that cause *carbon build-up.
The main reason, is that fuel and added detergents are not hitting the back of the intake valves.
By injecting the fuel directly into the cylinder instead of at the back of the valve, the gasoline
and detergents can’t clean the valve and port.
Second, leaner mixtures and higher combustion pressures can make the problem worse over time.
A direct fuel injection motor produces more energy from a given amount of fuel and air than a port
fuel injection engine. Today’s engines operate on a ragged edge between optimal efficiency and a
misfire. There is not much room for error like hot spots in the combustion chamber or a worn spark plug.
When a hot spot or sub-optimal flame front is created due to *turbulent air, the amount of unburned
fuel in the combustion chamber increases. When the valve opens during the intake stroke, it might
come in contact with these byproducts, and unlike the exhaust valve, the gases passing by are
not hot enough to burn it off.
Third, the intake valve goes into the combustion chamber, regardless if it is port fuel injected or direct
injected. When it does, for that small period of time, it is exposed to combustion byproducts that can
stick to the neck of the valve. If the last combustion cycle was less than optimal, the intake valve is
Some direct injection vehicles with variable valve timing can expose the valve to combustion byproducts
as the valves adjust, which creates a scavenging effect to either pull or leave behind a small amount
of exhaust gases in the chamber to control NOX emissions. Also, some turbocharged direct injection
engines will leave the intake and exhaust valves open at the same time in order to keep the turbo
spinning to reduce lag.
Believe it or not, there is no one sure fix, and no permanent fix. The number one method for preventing
a *carbon build-up problem is updating the engine management software. New software can reduce carbon
deposits by reducing the exposure of the valves to conditions that cause carbon build-up by adjusting
valve and spark timing. Spark plug replacement can reduce the amount of unburned fuel in the combustion
chamber that can stick to a valve. Fuel injector cleaning can help injectors maintain the correct spray
geometry. Scheduled oil changes can keep the camshaft actuators working in optimal condition to control
the exposure of the intake valves.
Oh, and don’t assume that you will find a TSB saying that a reflash of the ECM will correct a carbon build-up
problem because most of the updates will be contained in normal housekeeping that may never say anything
about a problem. You will have to check the OEM’s website to see if the vehicle has the latest version of
the software. Usually though, every time you take your car into the dealer, they will update the ECU.
Some have blamed the positive crankcase ventilation (PCV) systems for leaving an oily film on the intake
valve that is then baked into carbon. Some blame the valve overlap during the intake stroke that
eliminates the need for an EGR valve. Diesels have a CCV, almost the same thing, and mine has been
connected to a catch can and vent for a long time.
From what I read, you had your valves manually cleaned, by that, it indicates that the heads are removed
and the valves cleaned. There is no MANUAL cleaning with sprays and chemicals, you can do that on
your own. Sport mode changes the shift points, and fuel curve, I don't see that making any real
difference. The car shuddering BAD is not a valve seating issue, you have an injector, plug, or other
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