Actron Digital Multimeter CP7676 - Manual (Page 27)

4
CYL 5
CYL
6
CYL
8
CYL
2K 200
200
750
20
2
20M
2M
200K
20K
OHMS
RPM
X10
750V AC
200V DC
COM V
DWELL
4
CYL
5
CYL
6
CYL
8
CYL
27
Measuring Fuel Injector Resistance
Fuel injectors are similar to solenoids. They
contain a coil that is switched ON and OFF by
the vehicle computer. This test measures the
resistance of this coil to make sure it is not an
open circuit. Shorted coils can also be
detected if the specific manufacturer
resistance of the fuel injector is known.
4. Disconnect wiring harness from fuel
injector - Refer to vehicle service
manual for procedure.
5. Connect RED and BLACK test leads
across fuel injector pins.
Make sure you connect test leads across
fuel injector and not the wiring harness.
6. Turn multimeter rotary switch to desired
OHM range.
If the approximate resistance is unknown,
start at the largest OHM range and
decrease to the appropriate range as
required. (see Setting the Range on page
6)
7. View reading on display - Note range
setting for correct units.
• If display reading is 10 Ω or less, subtract
test lead resistance found in Step 3 from
above reading.
• Compare reading to manufacturers
specifications for fuel injector coil
resistance.
• This information is found in vehicle
service manual.
8. Test Results
Good Fuel Injector resistance: Resistance
of fuel injector coil is within manufacturers
specifications.
Bad Fuel Injector resistance: Resistance
of fuel injector coil is not within
manufacturers specifications.
NOTE: If resistance of fuel injector coil is
within manufacturers specifications, the
fuel injector could still be defective. It is
possible that the fuel injector is clogged or
dirty and that is causing your driveability
problem.
Test Procedure (see Fig. 26):
1. Insert BLACK test lead into the COM
test lead jack.
2. Insert RED test lead into the
V
test
lead jack.
3. Turn multimeter rotary switch to 200 Ω
range.
Touch RED and BLACK multimeter leads
together and view reading on display.
Display should read typically 0.2 - 1.5 Ω .
If display reading was greater than 1.5 Ω ,
check both ends of test leads for bad
connections. If bad connections are found,
replace test leads.
Fig. 26
Typical Fuel
Injector
Black Red