
TROUBLESHOOTING AND ELECTRICAL SYSTEM
Test Procedures
Page 11-32
2005 FE350 Gasoline Vehicle Maintenance and Service Supplement
11
Test Procedure 16A – Ignition Coil – In Vehicle Test, Continued:
5. Test the secondary coil separately from the spark plug cap.
5.1. Using a multimeter set to 20k ohms, place the red (+) probe of the meter into the end of the spark
plug wire and place the black (–) probe on a clean unpainted surface of the engine or frame
(Figure 11-31, Page 11-31)
. If the resistance is between 6.0k - 11.0k ohms, the secondary coil is
within acceptable limits. If the resistance is not between 6.0k - 11.0k ohms, bench test the ignition
coil.
See Test Procedure 16B – Ignition Coil – Bench Test on page 11-32.
6. If the preceding tests indicate that the ignition coil resistance readings are within acceptable ranges, but
the coil fails to function properly, proceed to the following bench test procedures.
Test Procedure 16B – Ignition Coil – Bench Test
1. Remove the coil from the engine.
See Ignition Coil Removal, Section 12, Page 12-25.
2. Using a multimeter set to 200 ohms, measure the primary coil resistance.
2.1. Place the black (–) probe of the meter on the terminal on the ignition coil (1), and place the red (+)
probe on the core (2)
(Figure 11-32, Page 11-32)
.
2.2. If the resistance is not between 0.6k - 1.7k ohms, replace the ignition coil.
3. Using a multimeter set to 20k ohms, measure the resistance of the secondary coil and spark plug cap
together.
3.1. Place the red (+) probe of the meter into the end of the spark plug cap that normally connects to
the spark plug (3) and place the black (–) probe on the core (2)
(Figure 11-33, Page 11-32)
.
Figure 11-32 Primary Coil Resistance – Bench Test
Figure 11-33 Secondary Coil and Cap Resistance –
Bench Test
2m
20
m
200
m
2k
200
200
200
200
20
2
200
m
500
20k
200k
2000
k
1000
OFF
WAVETEK
5XL
V
V
V
A
!
!
COM
200nA
MAX
1000 ---
750V
FUSED
2
1
200 OHM
SETTING
2m
20
m
200
m
2k
200
200
200
200
20
2
200
m
500
20k
200k
2000
k
1000
OFF
WAVETEK
5XL
V
V
V
A
!
!
COM
200nA
MAX
1000 ---
750V
FUSED
2
3
SECONDARY COIL
20k OHM
SETTING