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FUEL INJECTION
Electric Fuel Pump Voltage/Pressure Test
NOTE: The Digital Diagnostic Terminal (DDT) can implement a load test for the electric
fuel pump. If the electric fuel pump does not appear to run, it is recommended that the DDT
load test be performed first before performing the following voltage test.
Purpose: If insufficient electrical power is available at the pump, no or low fuel pressure will be developed.
1. Disconnect electric fuel pump harness connector.
2. Set volt meter to read battery voltage and connect black test lead to BLACK wire in the
fuel pump connector, positive test lead to positive wire (RED/BLUE) of fuel pump con-
nector (engine harness end).
a -
3. Turn key to RUN position. Battery voltage will be applied to the RED/BLUE lead for
about 2 seconds.
Results: If battery voltage is not present, inspect battery, battery connections and harness for corrosion, dam-
age or loose connections. If correct battery voltage is present, replace electric pump.
NOTE: If electric fuel pump runs but fuel pressure is low, perform amperage draw test on
electric pump. Amperage draw should be 4 amperes
high, replace pump.
Page 3B-28
Fuel Pump Harness Connector – Positive test lead to RED/BLUE wire and
Negative test lead to BLACK wire (engine harness end)
a
0.5 amperes. If amperage draw is
58794
90-883728 JULY 2001
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Troubleshooting
Need help?
Do you have a question about the 150 EFI and is the answer not in the manual?
Questions and answers
I have a 1998 mercury 150 efi replaced the fuel pump stated up then I put water to it it wanted to die
Your 1998 Mercury 150 EFI engine may want to die after replacing the fuel pump due to one or more of the following reasons:
1. Faulty Fuel Pressure Regulator: Even though many assume it doesn't fail, a bad regulator can cause incorrect fuel pressure, leading to poor engine performance or stalling.
2. High-Pressure Fuel Pump Issues: If the high-pressure pump has had water in it or sat dry, it can go bad, even if recently replaced.
3. Electrical Problems: Issues like a melted fuse holder can drop power to the ECU, affecting engine performance or causing it to shut off.
4. Overcharging Voltage: If voltage at wide-open throttle (WOT) is too high, it can cause the ECU to shut off or act erratically.
5. Fuel Quality or Treatment: Contaminated fuel or improper treatment can also affect engine performance.
Each of these should be checked to identify the root cause.
This answer is automatically generated