Throttle: common defects and their signs

1. Breakdown of throttle valve position sensor.
   • The engine stalls at gear changing.
   • Jerks appear during acceleration.
   • Exhaust gases become black and get specific gasoline smell.
   • Operation of the engine is unstable at idle.
   • “Check Engine” indicator activates.
   • Detonation of the engine occurs frequently.
   • Popping occurs in the intake manifold or the silencer.
   • Troubles at the engine start occur.
2. Soiling.
   • Fuel consumption increases.
   • Power of the engine decreases.
   • Failures and delays appear in operation of the engine.
   • The engine stalls if the accelerator pedal is suddenly pressed out.
   • The accelerator pedal jamms.

How to repair or replace throttle?

In order to remove the car defects signs, noted above, it is recommended to perform cleaning of the throttle. Usually, this procedure should be carried out not oftener than every 100 000 operational kilometers, and also according to recommendations of the vehicle manufacturer.

The cleaning procedure is easy and any car owner will be able to handle it. You will need a standard set of wrenches and screwdrivers, cloth and special cleaning compound. It is very important to use soft materials instead of brushes, also not applying excessive force.

In order to clean the throttle unit, firstly, you need to demount it. Actions for demounting may be slightly different for cars of various models, so you need to familiarize yourself with technical documentation upfront. Basically, to remove the component you need to do the next:

1. In case if the car construction provides supply of antifreeze to the throttle, disconnect supplying hoses and obturate them with the bolt or the plug.
2. Disconnect wires from the throttle valve position sensor.
3. Disconnect the crankcase ventilation hose from the air-supply sleeve.
4. Loosen the fastening of the air-supply sleeve and disconnect it from the throttle intake.
5. Detach the wiring from the idle air-control valve.
6. Loosen fastenings of the cooling liquid supply hose and disconnect it from the throttle intake.
7. Disconnect the cable of the throttle actuator (for cars with mechanical throttle).
8. Unscrew the nuts, fastening the throttle unit and remove it.

Now, you need to clean the demounted throttle. WIth the help of the cleaner and cloth, clean the component and all units channels. Pay special attention to the positive crankcase ventilation channel, which is usually the most soiled. After cleaning, install the part into its place and check engine operability. If the defects signs didn't disappear, the throttle is to be replaced, taking into account the algorithm, noted above.

All works are carried out only after cooling down of the engine.