Mercury 150 EFI Service Manual page 268

FUEL INJECTION
Condition
Poor Acceleration – Idles Ok,
Top Speed Ok (Continued)
Engine Surges Between 4000
And 5000 RPM
Engine Idles Ok But Stumbles At
Off Idle Speeds
Engine Idles Rough (May Lean
Sneeze) – Acceleration Ok; Full
Throttle Ok
Page 3B-36
Possible Source
– Timing Not Advancing.
– Intermittant Ignition Coil Fail-
ure.
– Final Filter Clogging.
– T.P.S.
– Injector Connector Problem.
– Vapor Separator Flooding
Over.
– Injector Filter Clogged.
– Improper EFI Setup.
– Failed Ignition Coil.
– Failed Or Disconnected EFI
Sensors.
– Fuel Delivery Problem.
– Manifold Fuel Leak.
– R.F.I.* Problem.
– Induction Manifold Air Leak.
– MAP Sensor Failure.
– Improper EFI Setup.
– MAP Sensor Failure.
Action
Check Timing Advance with DDT.
Refer to Section 2A Electrical
and Ignition for tests.
Perform Final Filter Check.
Check TPS Operation with DDT
Perform DDT Load Test and
Ohms Test.
Check for fuel coming out of va-
por separator vent hose.
Must be determined by elimina-
tion; mechanical, electrical and
load tests
Refer to Section 2C Electrical
and Ignition for proper EFI set up
procedures.
Refer to Section 2A Electrical
and Ignition Tests.
Perform EFI sensor tests.
Follow Low/High Pressure Fuel
Route Flow Charts and Fuel Rail
Electrical/Fuel Determination
Flow Chart.
Perform Induction Manifold Leak
Check.
Install BPZ8HS-10 Spark Plugs.
Check manifold cover gasket,
manifold to reed block housing
gasket and reed block housing to
crankcase gasket.
Refer to page 3B-34.
Refer to Section 2C Electrical
and Ignition for proper EFI set up
procedures.
Refer to page 3B-34.
90-883728 JULY 2001