Engine Hard Start - Diagnosis
310-O2XK8
DATE
12/97
Engine Hard Starting - Diagnosis
MODEL
1997 MY-ON XK8 Range
VIN
001001-ON
Issue:
This bulletin provides a diagnosis procedure to follow in case of a customer complaint of poor or hard starting.
To assist in a methodical diagnosis, this bulletin includes an Engine Start Report Form which should be copied and filled out.
Action:
Make a copy of the Engine Start Report Form shown in this bulletin. Fill in the details of the occurrence on the copy and fax it to the Product Investigation Dept. at (201-818-9763). There are four areas which should be checked when a starting problem is encountered and they are listed in order of possibility.
^ Tank Pressure Control Valve, (TPCV), known as a "Rochester Valve"
^ Spark Plugs
^ On 1998 MY-ON vehicles, the Key Transponder Module, (KTM).
Transmission Rotary Switch/Harness
Flow Chart:
TANK PRESSURE CONTROL VALVE (TPCV)
Connect a hand vacuum tester to the TPCV vacuum port, as shown in Illustration 1 and follow the flow chart.
SPARK PLUGS
If the engine failed to start, check the spark plugs for carbon buildup. If carbon buildup is found, the spark plugs must be changed. Set the spark plug to a revised gap of 1.3 mm (0.051 in). Check the throttle linkage to ensure that wide open throttle is possible.
KEY TRANSPONDER MODULE (KTM) 1998 MY-ON
^ If the engine failed to start, the exact conditions of the start procedure must be reproduced before the KTM is replaced.
^ A failure to start due to a KTM problem occurs when the ignition key is turned quickly through position I & II to then operate the starter motor to turn the crank, without waiting for the instrument panel warning lights to light up.
^ The starter motor will turn the crank normally without the ignition firing.
^ If the key is then released and turned again, as described, then the engine will fire and run normally.
^ If the faulty start procedure can be reproduced, the KTM should be replaced by latest version KTM, Part Number LNC 2665AA.
^ The keys must be reprogrammed to match the replacement KTM.
TRANSMISSION ROTARY SWITCH/HARNESS
If an engine can be turned by the starter motor, but fails to start and the gearchange "J gate" is not illuminated, the fault could be in the rotary switch harness. This fault can be intermittent or continuous.
DTC P0706 will be stored and DTC's P1516 and P1517 may be stored.
The cause of this fault is the entry of water into either the rotary switch or the rotary switch harness connector, either of which will require the replacement of the rotary switch and harness.
Warranty Information:
This is bulletin is issued to assist in diagnosis only. Refer to the Warranty Codes and Repair Operation Times manual for fault codes and labor times.