This bulletin has been developed to address complaints of an engine which cranks normally but is difficult to start or will not start at all.
- Connect CONSULT. If the vehicle at hand is not CONSULT compatible, connect a tachometer (digital readout if possible).
- 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. If the engine will not start, clean and dry the spark plugs and attempt starting.
- Run the engine at 2,000 rpm (no load) for two minutes and shut the engine off.
- Check the oil level and correct if necessary. If the oil level is overfull and has a gasoline odor, change the oil and filter. If the crankcase is overfull, idle speed adjustment may be affected.
- Disconnect the TPS connector. Now re-start the engine. When the TPS is 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 by turning the adjusting screw on the IACV-AAC valve until the engine will idle. NOTE: On 1989-1994 Maxima vehicles with the VG30E engine, the IACV-AAC valve is a “stepper motor” type valve. To set base idle on these vehicles, set the ECCS ECM mode screw fully clockwise. This will close the IACV-ACC valve completely to allow base idle speed adjustment. Return the ECCS ECM mode screw fully counterclockwise after setting the base idle.
- Rev the engine two to three times to 2,000-3,000 rpm, then allow it to idle (with all accessories off).
- Check the ignition timing with a timing light and adjust to specification (if necessary).
- If the vehicle is not CONSULT compatible, monitor idle speed using the tachometer. If using CONSULT, monitor the idle speed (CMPS-RPM) on the CONSULT screen.
- Check the idle rpm and adjust to specification using the screw on the IACV-ACC valve.
- Turn the engine off and reconnect the TPS.