Engine - Cranks, No Start/Hard Start
Classification:EC97-020a
Reference:
1TB97-041a
Date:
March 18,1998
Title:
ENGINE CRANKS, BUT WILL NOT START OR IS HARD TO START
APPLIED VEHICLES:
All models 1990-97
SERVICE INFORMATION
Use this bulletin if the engine cranks over normally, but is difficult to start or will not start at all.
This situation may be caused by small carbon deposits falling onto the intake and exhaust valve sealing surfaces which results in loss of compression.
NOTE: On 1997 or later Q45 (FY33) models, the above symptoms will also result if the IPPS (Infiniti Personal Protection System - NATS) malfunctions. Use CONSULT to check for stored IPPS-related DTC codes for any FY33 models. If necessary, refer to page EL-422 of the 1997 service manual for further IPPS diagnosis.
SERVICE PROCEDURE
Check the base engine idle speed using 'Procedure A'. Once complete, perform 'Procedure B' according to the vehicle model being worked on.
Procedure A
1. Connect CONSULT.
2. Start the engine (the accelerator may have to be depressed 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, dry and reinstall the spark plugs and attempt to start the engine again.
CAUTION: Disable the ignition system when cranking the engine with the spark plugs removed.
3. Run the engine at 2000 rpm (no load) for 2 minutes. Then shut the engine off.
4. Check the oil level and correct if necessary (between the "L" and "H" marks on the dipstick). If the oil level is overfilled and has a gasoline odor, change the oil and filter before performing this procedure. If the crankcase is overfilled with oil, idle speed adjustment may be affected.
5. Disconnect the throttle position sensor (TPS) connector. Now re-start 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" (AAC off) 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 1990-1992 M3Os (F31), the IACV-AAC valve (rather than the TPS) must be disconnected to adjust the base idle speed.
6. Rev the engine two or three times to 2000-3000 rpm, then allow it to idle (all accessories "off").
7. Check the ignition timing with a timing light and adjust it to specification (if necessary).
8. Using CONSULT, perform the following procedure:
CONSULT TOOL:
Monitor the idle speed (CM PS.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 table below 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 & EC or EC section in recent service manuals) section, and perform the "IDLE SPEED/IGNITION TIMING/IDLE MIXTURE RATIO INSPECTION" procedure.
10. Turn the engine off, and re-connect the TPS.
Procedure B
Perform the following procedure based on the vehicle model being worked on.
Q45
1. If the base idle speed is within specification and the vehicle has experienced hard starting following a short driving cycle, do the following depending on model year:
Figure 1:
1990-1996: Install the countermeasure starter motor assembly and power steering heat insulator (see Parts Information on page 5). Refer to the appropriate service manual (EL section) for installing the starter motor. Refer to Figure 1 for installing the power steering heat insulator.
1997: Install the countermeasure ECM. Refer to the appropriate service manual (EC section) for installing the ECM.
2. Review the starting information (see page 4) with the customer.
J30
1. If the base idle speed is within specification and the vehicle has experienced hard starting following a short driving cycle, install the countermeasure starter motor assembly. Refer to the appropriate service manual (EL section) for installing the starter motor.
2. Review the starting information (below) with the customer.
3. If the customer continues to experience hard starting after installing the countermeasure starter motor assembly, please contact TECH LINE for assistance.
I30
1. If the incident continues, refer to Infiniti Technical Bulletin ITB97-036/EC97-028 for countermeasure information.
2. Review the starting information (on page 4) with the customer.
G20
1. If the incident continues, contact your region for assistance.
2. Review the starting information (on this page) with the customer.
QX4
1. The VG33E engine used in the QX4 is not prone to hard starting caused by carbon deposits. If a customer reports hard starting under cold/high altitude conditions, please refer to Infiniti Technical Bulletin ITB97-025/EC97-004 for countermeasure information.
2. Review the Cold Weather Starting Information (below) with the customer.
M30
1. The VG30E engine in the M30 is not prone to hard starting caused by carbon deposits.
2. Review the starting information (below) with the customer.
Starting Information for Customer
Short Driving Cycles - Q45. J30, I30 and G20
Modern multi-valve engines designed for efficient low-friction operation may sometimes experience carbon build-up on the valves after driving a very short duration (less than 1 minute). A hard start or no start incident may occur on the next starting attempt. If this pattern is observed, the vehicle can be started by following the cold weather starting procedure below.
Cold Weather Starting - All Models
During cold whether, Nissan suggests the following procedure to make starting the vehicle easier when this incident occurs. This procedure is a continuation of the procedure outlined in the owners manual and should be used to remedy a "No Start" condition when the ambient temperature is low.
1. Depress the accelerator pedal approximately 1/3 of the way to the floor.
2. Hold the accelerator pedal in this position and crank the engine.
3. Once the engine has started, release the accelerator pedal. (Do not race the engine while warming it up.)
4. If the engine does not start within 10 seconds, wait at least 10 seconds and repeat steps 1 through 3.
Once the engine is started in cold weather conditions, run the engine for a minimum of 2 to 3 minutes before shutting it off. Starting and stopping the engine over a short period of time may make the vehicle more difficult to re-start. This type of usage may also adversely affect a vehicle's fuel economy.
Another factor that may affect a vehicle's starting performance in cold whether conditions is the viscosity or thickness of the engine oil that is used. An API SG or SH quality 5W-30 is the preferred engine oil to be used year-round for most models. In colder weather, oil that is rated 5W-30 will not thicken as much as a 10W-30 rated oil; this makes it easier to start the engine and maintain a stable idle during warm up.
PARTS INFORMATION
CLAIMS INFORMATION
When applicable, standard claims coding applies.