No Pulse

KAREN FRANCISCO

MEMBER
2004 FORD F-150
5.4L
V8
RWD
AUTOMATIC
200,000 MILES

Running rough like not getting fuel. Changed oxygen sensor in front driver side behind motor. Changed all plugs and three or four coils. Showed gas was lean is why changed sensor. Now after replacing all plugs it is not getting a pulse to number one it gave three quick blinks then nothing. Appears all injectors are getting fuel but number one not wanting to get enough fuel to open. Help.

1 Reply

JDL

MECHANIC
16,098 POSTS

Your saying you loose fuel injector pulse on number one cylinder? In the diagram, red wire is voltage, should be hot all the time engine is idling or cranking, If you losing voltage have to backtrack the red wire circuit. Tan wire is ground controlled by computer. See if your losing voltage or ground? Any applicable trouble codes?
Could be fuel injector problem? You can do an ohms test on fuel injectors. Hopefully it would show anything obvious. I do not have that spec in front of me. Just do an ohms test on any working injector, everything off, compare readings to other injectors. If you find one fuel injector where the reading is way different than the others, I would probably replace it. Just my opinion.

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