
TROUBLESHOOTING AND ELECTRICAL SYSTEM
Test Procedures
2005 FE350 Gasoline Vehicle Maintenance and Service Supplement
Page 11-33
11
3.2. If the resistance is between 12.0k - 14.0k ohms, the secondary coil and spark plug cap are within
acceptable limits; proceed to step 6 on page 11-33. If the resistance is not between 12.0k - 14.0k
ohms, the spark plug cap and secondary coil must be tested independently from each other.
4. If not previously tested, test the spark plug cap separately from the secondary coil.
4.1. Remove the rubber gasket (1) on the plug cap (2) by rolling back the gasket onto the spark plug wire
(3)
(Figure 11-28, Page 11-30)
.
4.2. Remove the cap from the wire by turning the cap counterclockwise three or four revolutions while
gently pulling it off the wire
(Figure 11-29, Page 11-30)
.
4.3. Using a multimeter set to 20k ohms, place the red (+) probe of the multimeter into the end of the
spark plug cap that normally connects to the spark plug and place the black (–) probe into the end
of the cap with the internal screw
(Figure 11-30, Page 11-31)
. If the resistance is not between 4.5k
- 6.0k ohms, the cap has failed and must be replaced. Proceed to the next step with the spark plug
cap still removed.
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 the core (2)
(Figure 11-34, Page 11-33)
. 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, the ignition coil has failed and must be replaced.
6. If the preceding tests indicate that the ignition coil resistance readings are within acceptable ranges, but
the coil fails to function properly, replace the ignition coil and cap.
Figure 11-34 Secondary Coil 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
20k OHM
SETTING