- Checking the Basics

The DIAGNOSTIC CIRCUIT CHECK should be performed before using this section. The purpose of this is to locate the source of a driveability or emissions problem when other diagnostic procedures cannot be used. This may be because of difficulties in locating a suspected sub-system or component.

Many driveability related problems can be eliminated by following the procedures found in Service Bulletins. These bulletins supersede this manual. Be sure to check all bulletins related to the complaint or suspected system.

If the engine cranks but will not run, use CHART A-3. Related Tests, Information and Procedures
The sequence of the checks listed is not intended to be followed as on a step-by-step procedure. The checks are listed such that the less difficult and time consuming operations are performed before more difficult ones.

Most of the symptom procedures call for a careful visual and physical check. The importance of this step cannot be stressed too strongly. It can lead to correcting a problem without further checks, and can save valuable time. This procedure includes checking the following.
- Vacuum hoses for splits, kinks, and proper connections, as shown on the underhood Emission Control Information label.
- Throttle body and intake manifold for leaks.
- Ignition wires for cracking, hardness, proper routing, and carbon tracking.
- Wiring for proper connections, pinches, and cuts.