For 1990-2009 cars

# EFFECTS OF TOP ENGINE CLEANER CARBURETED ENGINES

EFFECTS OF TOP ENGINE CLEANER ON THE CATALYTIC CONVERTER

#### MODELS AFFECTED: ALL 1981 THRU 1986 CARBURETED ENGINES

Top Engine Cleaner (TEC) is effective in cleaning, deposits from engine components. GM part numbers 1050002, 1052626 or their equivalents may be used for this purpose.

Although TEC does not affect catalyst performance when used as directed, misuse of the product may result in appreciable losses in catalytic converter efficiency due to high temperatures caused by the extra rich mixture. For this reason, TEC must be used according to its label with particular attention to the following:

1. Allow the engine to run at idle for 10 to 15 minutes in order to reach operating, temperature before adding TEC.

- This will allow the converter to stabilize at a lower temperature, and, thus, minimize the chance of thermal degradation upon introduction of TEC into the system.

- Divert the AIR from the converter in the following manner:

2. Disconnect the AIR diverter valve solenoid (the connecting wires are pnk/blk and blk/pnk) for the carbureted versions of all series cars.

- The AIR system, uses an engine driven pump to direct air into either the cylinder head, exhaust ports, the catalytic converter, or the air cleaner. The AIR Management valve performs the air switching and divert functions. De-energizing the AIR divert valve solenoid diverts the air to the atmosphere. The AIR check valve prevents air from being injected into the converter while TEC is being added, reducing the possiblity of excess TEC being ignited in the catalytic converter.

3. Remove air cleaner.

4. Increase engine speed and pour about 1/3 can of cleaner tbrough carburetor throat fast, stalling engine. (Note: Do not pour cleaner after engine stalls.)

5. Turn off ignition.

6. After 15 minutes, start engine.

7. At fluctuating idle speeds, slowly pour balance of cleaner through carburetor throat, rinsing out deposits from combustion area.

8. Restore AIR management systems by reconnecting the AIR divert valve solenoid.

Use of TEC in accordance with these instructions permit effective performance of the product without damaging the catalyatic converter.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.