Initial Inspection

BATTERY STATE OF CHARGE
Batteries in a state of partial discharge can have a dramatic effect on control units and related components.

POSITIVE BATTERY CABLE INTEGRITY
All B+ connections must be in perfect condition for trouble-free electronic system operation. Refer to Diagrams/Electrical for B+ connections and splices.

FUSE INTEGRITY
Fuses are employed to prevent possible damage to electrical components and wiring harnesses. The fuses and their connections must be without dynamic resistance.
- Dynamic resistance can only be checked using the voltage drop method of testing.

NEGATIVE GROUND CONNECTIONS
As all electrical circuits are a circle, all B- connections must also be checked and verified to be in perfect condition.
- A poor "common" ground point will cause seemingly unrelated systems to influence one another.
- High current systems which encounter a poor "common" ground can back feed through other electrical systems causing unusual operation and perhaps inexplicable component failure.
- As with the B+ side of the electrical system, the ground side should be checked dynamically using the voltage drop technique.

THROTTLE AND SPEED CONTROL CABLES
Metal cables attached to the engine or transmission which appear overheated and/or discolored indicate the need to thoroughly test all ground connections.

POWER SUPPLY RELAYS
The system relay as well as its' plug connection can be a source of intermittent operation which will not set a fault in control unit fault memory.

CRANKSHAFT POSITION/DISTRIBUTOR PICK-UP
Hall Effect switches should be checked statically and dynamically. Physical mounting and condition of the sensor must be assured.

SECONDARY COMPONENTS/WIRING
The secondary ignition system should be checked visually as well as with a suitable engine analyzer and scope.
- All components should be examined for tight connections and freedom from carbon tracking, moisture and corrosion.

FUEL DELIVERY
Fuel pressure should be within specifications during cranking.

Fuel pressure retention must be maintained between the fuel pump outlet and the pressure regulator after engine shutdown.

VALVE CLEARANCE
Out of specification valve clearance can significantly impair engine performance.
- Valve clearance adjustment procedures should be strictly observed.

SPARK PLUGS
Verify spark plug type, condition, and gap are as specified.

AIR/FUEL RATIO
When troubleshooting idle quality or driveability complaints consider the following:
- Injector spray pattern
- Vacuum and/or air leaks
- EVAP purge system
- Engine oil dilution
- Contaminated fuel or unapproved additives
- Carbon build-up