Engine Information

Item #1. Check Engine Light (Code 34)

Code 34 will set if the following conditions are met:

^ Engine running

^ Mass Air Flow Sensor (MAF) disconnected, faulty MAF relay or MAF signal circuit shorted to ground.

OR

^ Air flow less than 2 grams per second (low frequency)

To correct a Code 34 check engine light, first make sure that the MAF Relay is working and supplies + 12 volts to the MAF Sensor. This can be accomplished by connecting a test lamp between ground and the "+" terminal of the MAF Sensor harness. With the ignition "ON", the test lamp should light. If the lamp doesn't light, check for an open in the + 12 volt supply or a faulty relay.

If power is supplied to the MAF sensor, use the standard fault tree for check engine light (Code 34) in Section 6E3 of the Service Manual.

Item #2. Engine Surge Item #2A

If the vehicle exhibits surge, follow procedures in Section B - Symptoms, Section 6E3 of the Service Manual for diagnosing surge. Particular attention should be given to:

^ Checking rear spark plug wires for heat damaged wires. Replace if damaged.
^ Checking spark plug wire boots for evidence of carbon tracking. If carbon tracking is present in spark plug boot replace both spark plug and spark plug wire.

Item #2B

If the surge is not corrected, installation of the later production parts should correct the condition.

^ Install the latest PROM unless the ECM already has it. (This can be done by using Chart I).

The latest PROM has revised EGR scheduling when the torque converter is engaged. This should reduce surge (TCC chuggle).

^ If the car is a Pontiac 6000 or STE, install a new air cleaner housing which utilizes a honey-comb air flow screen. This is provided in a service kit (P/N 25097022) which contains the air cleaner housing, gasket, and clamp.

After installing this new housing the car should be parked and the engine allowed to cool to ambient temperature; then cold started and driven a minimum of three miles to update the ECM memory.

NOTICE: During the first cold start after installing the new air cleaner housing the engine may hesitate and possibly backfire until the ECM memory is updated.

Item #3. Engine Hesitation

If the engine exhibits hesitation during acceleration when the engine is cold, install the following parts to correct the problem.

^ Install the latest PROM unless the ECM already has it. (This can be done using Chart I).

^ If the vehicle has early production injectors, install the revised injectors which have a revised spray pattern. The new injector is part of a kit P/N 17111297; six (6) kits required per engine.

NOTICE: Injectors with the correct spray pattern have already been installed on engines with a build date code of 0107 (January 7th) or later.

Example: T 01 07 CAF

This code is stamped on the horizontal machined surface of the block just forward of the intake manifold.
If the engine continues to exhibit a hesitation after the preceding changes, follow procedures for hesitation diagnosis in Section 6E3 of the Service Manual.

NOTICE: One of the steps in the Service Manual is to perform the injector balance test. It is important that this test be performed to identify restricted injectors. If the injectors are plugged or restricted, clean the injectors using recommended service procedures.

Warranty Information

Reference Chart II.