Diagnostic Instructions
Circuit/System Description
The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks but Does Not Run diagnostic table directs the service technician to the appropriate system diagnosis.
Diagnostic Aids
If the cause of an engine cranks but will not run condition has not been found, inspect for the following conditions:
• | Hard starting only in cold ambient temperatures. These may cause an intermittent condition that may not occur in the service bay: |
- | Ice blockage at the fuel pickup in the fuel tank--This will be a high vacuum in the supply lines while cranking, and the problem will disappear after the vehicle is brought in the service bay. It may also exhibit a start and stall condition
or a starting condition with no acceleration. |
• | The correct cranking speed is 100 RPM cold and 180 RPM hot. |
• | Low engine coolant may cause the engine to shut down. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Special Tools
CH-48027
Vacuum Gage
Circuit/System Verification
Important: This diagnostic assumes the cranking speed is within specifications.
- If DTCs P0090, P0191, P0193, P0335, P0336, P0340, P0602, P0603, P0604, P0606, P0642, P0643, P064C, P0698, P0699, P2510 are set diagnose those DTCs first.
- The engine starts and runs.
⇒ | If the engine does not start and run perform the Circuit/System Testing. |
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Inspect for the following conditions:
• | Inadequate fuel in the fuel tanks. |
• | A plugged air filter collapsed air intake duct |
- Install the
CH-48027
to the fuel rail service port and crank the engine.
⇒ | If more than 5 inches Hg of vacuum was present during cranking, replace the fuel filter and inspect the fuel system restrictions. |
- Perform the Engine Compression Test. Refer to
Engine Compression Test
.
Important: During the replacement of the injectors, inspect the inlet and outlet fittings for corrosion or contamination. Refer to
Contaminants-in-Fuel Diagnosis
.
⇒ | If any fuel vapor was emitted during the engine compression test, replace the affected fuel injector. |
- Assemble all disconnected components. Prime the fuel system to at least 10 psi. Attempt to start the engine.
Repair Instructions
Fuel Injector Replacement
Repair Verification
The engine starts and runs.