TM 9-2320-363-20-1
Section 4
TROUBLESHOOTING CHARTS
D. CHART -3 - ERRATIC PERFORMANCE AND NO CODES
This is a helpful hints chart. It assumes that you have received no codes, made all the basic mechanical checks first,
could not find the problem, and suspect the DDEC III system to be at fault. Based on the particular symptom here's what
to look for:
SYMPTOM
WHAT TO LOOK FOR
Can't get full power
Plugged fuel filters.
Hose not connected to Turbo Boost Sensor (TBS).
Verify injector calibration(s) are correct.
1.
Can't get full throttle.
Miscalibrated Throttle Position Sensor (TPS). See
Step 21-4 for TPS adjustment page 3-345.231.
2.
Runs rough, misses and/or occasionally stalls.
Proper gapping of Timing Reference & Synchronous
Reference Sensors (SRS and TRS). See Step C2-8
or C2-9 on how to check this.
Check for Fuel Leaks.
Loose battery power (ckt #240 or #241) ignition
(ckt #439) or ground (ckt #150) wires.
Check power contribution from each cylinder using
cylinder cut-out feature described in Diagnostic Data
Reader (DDR) instruction manual.
Check pulse wheel: missing teeth, damaged or
loose.
Check for signs of insulation wear on injector
harnesses.
3.
Engine idles high (after warm-up) or hangs
Check calibration of Throttle Position Sensor (TPS)
using procedure in Step 21-4 .(page 3-345.231). You
may have a TPS, linkage or pedal problem.
Check PTOSA signal line (ckt #510) for short to
voltage source.
4. Low road speed.
Determine road speed specifications for vehicle
manufacturer data. If road speed is less than specified
and all mechanical (driveline, speedometer) checks are
correct, then cruise control calibration is suspect. This
portion of the calibration can be reprogrammed using
(calibration configuration) on Diagnostic Data Reader
(DDR). Refer to DDR Instruction Manual for details.
Change 3 3-345.83
