Infiniti Tech Tip: Engine Cranks, but Won’t Start – UnderhoodService

Infiniti Tech Tip: Engine Cranks, but Won’t Start

If the owner of a 1997 Infiniti I30 complains of an engine that cranks over normally, but is difficult to start or will not start at all, follow the service procedure provided by Mitchell 1 in this tech tip.

If the owner of a 1997 Infiniti I30 (or the vehicles listed in the chart below) complains of an engine that cranks over normally, but is difficult to start or will not start at all, follow the service procedure below.

SERVICE PROCEDURE
1. Connect Consult unit.

2. Start the engine (the accelerator may have to be opened and/or the fuel pump fuse removed during cranking to get the engine to start), and warm it to operating temperature.

Note: If the engine will not start after performing the above procedure, clean and dry the spark plugs, and attempt to start the engine again.

3. Run the engine at 2,000 rpm (no load) for two minutes, then shut off the engine.

4. Check the oil level and correct if necessary (between the “L” and “H” marks on the dipstick). If the oil level is overfull and has a gasoline odor, change the oil and filter before performing this procedure. If the crankcase is overfull with oil, idle speed adjustment may be affected.

5. Disconnect the throttle position sensor (TPS) connector. Now restart the engine.

Note: When the engine is in this condition (TPS disconnected), the IACV-AAC valve and the ignition timing are held in a “fixed” position, and the idle speed is called “base idle.” If the engine stalls with the TPS disconnected, the base idle speed is adjusted too low. Temporarily increase the base idle speed by turning the adjusting screw on the IACV-AAC valve until the engine will idle.

Note: On 1990-’92 M30s (F31), the IACV-AAC valve must be disconnected to adjust the base idle speed.

6. Rev the engine two or three times to 2,000-3,000 rpm, then allow it to idle (all accessories should be off).

7. Check the ignition timing with a timing light and adjust it to specification (if necessary).

8. Using Consult, press Start. Then press Engine, Data Monitor and Start. Monitor the idle speed (CMPS*RPM) on the Consult screen.

9. Check the idle rpm and adjust to specification (if necessary ) using the screw on the IACV-AAC valve. The chart above shows ignition timing and base idle speed for some models.

If the model or model year you are working on is not listed, refer to the appropriate service manual (EF and EC) section, and perform the “Idle Speed/Ignition Timing/Idle Mixture Ration Inspection” procedure.

10. Turn off the engine and reconnect the TPS.

Courtesy of Mitchell 1.

For more information on Mitchell 1 products and services, automotive professionals can log onto the company’s website at www.mitchell1.com.

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