Daniel B. Martin

Okay, now I understand your point better. You are not opposed to cleaning the Throttle Body, but have a concern about "carburetor cleaner" as opposed to "throttle body cleaner". Valvoline http://www.valvoline.com/index_products.html has only one product in this category, and it is called Carb, Choke & Throttle Body Cleaner. Would you be comfortable with that?

Daniel B. Martin

Let's take this thread in another direction. Instead of fretting over the safe way of cleaning the Throttle Body interior, let's consider where the "gunge" comes from and what steps might reduce the build-up.

The Positive Crankcase Ventilation system draws fresh filtered air through a rubber hose from the engine air intake duct downstream of the air cleaner filter. This air mixes with "blowby" and oily vapors inside the engine crankcase area. This mix then passes through the Positive Crankcase Ventilation valve, through two short rubber hoses, and into the intake manifold, and is burned along with the air/fuel mixture.

If the PCV valve or associated hoses become clogged that oily blowby has to escape the engine somehow, and the easiest route is the normal fresh air intake path. In this case dirty air is introduced to the engine air intake duct, mixes with fresh air, and is swept along through the TB, the intake manifold, and is burned. Unfortunately the dirty air leaves deposits all along the interior of the plastic ductwork, the TB, and the intake manifold. When the engine is turned off some of this dirty air surrounds the Mass Air Flow Sensor and forms deposits on it. The MAFS is a vital engine control sensor. It is also sensitive, easily damaged, and expensive. Perhaps you have seen an air cleaner filter which had black "gunge" on the inside surface, which is not where you would expect it. That dirt came from blowby.

If your TB interior is dirty you should clean it with whatever kind of solvent you deem safe. Please follow up with some diagnostic investigation. Remove the Positive Crankcase Ventilation fresh air hose. This is the rubber hose, about as thick as your thumb, which connects to the driver's side of the front bank valve cover. It is easy to see and reach. With your engine idling use your finger or a piece of stiff paper to sense whether there is a vacuum (air being sucked into the engine) or pressure (air coming out of the engine) through that hose. If you find pressure, that is a trouble symptom.

If you have pressure, clean or replace the PCV valve. Verify that the rubber hoses which lead from the PCV valve to the intake manifold are clear. Repeat the pressure-or-vacuum test. If you still find pressure that is a sign of excessive blowby. Blowby is the term for combustion gases which sneak past the piston rings. Excessive blowby may indicate worn or broken piston rings, worn cylinder bores, or a damaged piston. This can be determined by a compression test.

ericdwong

I know there are plenty of "throttle body" cleaners on the market. I will have to say, I have used carb cleaner on my TB in my 90 Camry with 185,000 miles on it, and its still just fine..

Sonic

Stupid question time. You disconnect the PCV valve from the valve cover and check for suction, or remove the hose from the vacuum line and check for suction? I removed the PCV valve from hte valve cover, and found suction on the engine side of the PCV valve.

BTW, isn't it weird that we are now like 45 messages into a simple subject matter? That's orggers for ya, making something simple difficult.

Daniel B. Martin

Remove the thick-as-your-thumb fresh air hose which connects to the driver's side of the front bank rocker cover. There should be vacuum at that hose to draw in fresh air.

dmbmaxima2k2

iTrader: (1)

so true.