MerCruiser 305 CID (5.0L) Service Manual page 662

SERVICE MANUAL NUMBER 24
Chart A-5 (2 of 2): Fuel System Electrical Test
Step
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Index
90-861327--1 OCTOBER 1999
Was the "On-Board Diagnostic" (OBD) System Check
Performed?
a. Ignition OFF.
b. Remove fuel pump relay.
c. Ignition ON.
d. Using test light connected to ground, probe fuel pump
relay harness connector terminal "30."
Does Test Light Illuminate?
a. Ignition OFF.
b. Using a fused jumper wire, connect terminals "30" and
"87" of the fuel pump relay connector together.
c. Ignition ON.
Does Fuel Pump Run?
a. Ignition OFF.
b. Disconnect fused jumper wire.
c. Using a test light connected to battery positive (B+),
probe terminal "86" of the fuel pump relay connector.
Does The Test Light Illuminate?
a. Using a test fight connected to ground, probe terminal
"85" of the fuel pump relay connector.
b. Ignition ON.
Does Test Light Illuminate For 2 Seconds And Then Go
Off?
Check fuel pump relay fuse.
Is Fuse Ok?
Locate and repair faulty ECM connection at "J2-9" or repair
open in CKT 465.
Check for plugged fuel filter, vapor lock condition, restricted
fuel lines, disconnected hoses, and proper fuel level.
Locate and repair open in CKT 339 or CKT 902.
Locate and repair short to ground in CKT 339 or CKT 120.
Also check for contamination in fuel lines or fuel tank. If OK,
replace fuel pump and fuse.
Locate and repair open in CKT 120 or CKT 150. If okay,
replace faulty fuel pump.
Locate and repair open in CKT 450.
Action
DIAGNOSTICS
Yes No
PROCEED TO
Step 2. OBD
Step 3. Step 6.
Step 4. Step 11.
Step 5. Step 12.
Step 8. Step 7.
Step 9. Step 10.
Verify
–
Repair
Page 5G-35