TROUBLESHOOTING WITHOUT A DIAGNOSTIC CODE - CONTINUED
Table 1. Engine Troubleshooting - Continued.
TEST OR INSPECTION
8. Check the air intake and exhaust
1. Remove any blockages or restrictions
Engine Misfires, Runs
system for restriction and/or leaks (WP
and replace damaged air intake and
Rough, or is Unstable -
exhaust system lines or hoses (WP
2. If problem still exists, go to Test 9.
9. Perform Electrical Power Supply
If problem still exists, go to Test 10.
10. Use MSD to verify throttle signal is
If problem still exists, go to Test 11.
smooth from low to high idle positions.
If not smooth, perform Throttle
Position Sensor Circuit Test (WP 0013
11. Use MSD to determine if there are any
1. Troubleshoot any active diagnostic
active diagnostic codes for the fuel
2. If problem still exists, go to Test 12.
12. Use MSD to perform Injector Solenoid If problem still exists, go to Test 13.
Test. Determine if all injector solenoids
are being energized by the ECM. If not,
N OT E
It is not necessary to swap the injector trim files for this temporary exchange
of two injectors. Injectors must be properly installed and adjusted for this
13. Use MSD to perform Cylinder Cutout
1. If misfire problem stays with the
suspect injector, replace the suspect
Temporarily swap suspect injector
injector and install the new trim file for
from the misfiring cylinder with an
it (WP 0187 00). The other good
injector from a cylinder that is not
injector that was moved must first be
returned to its original position or its
cylinder cutout test to determine
trim file must be moved to its new
whether the misfire stays with the
suspect injector or with the original
2. If cylinder cutout test indicates that
misfire continues to be in same
cylinder, injector is not the problem.
Return the injectors to their original
position or move the trim files to the
new location. Investigate other
possible causes of misfire for the
problem cylinder, check valve lash
(WP 0179 00). If problem still exists,
go to Test 14.