fuel injection replacement
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Freshman User
Joined: Dec 2005
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fuel injection replacement
I have a 91' f150 5.0 im wondering what everyone thinks about my problem my truck seems to sputter and shake so i got a code scanner and the scanner told me there is a problem with my #4 injector so do i replace them all or is there anything that takes a little less work to fix this problem?
thanks
thanks
Senior User
Joined: Apr 2004
Posts: 424
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From: maui.HI
Getting to the injectors on these trucks aren't that hard. You only have to remove the upper intake. You will need to rig up a T40 torx bit with a long extension to get to one of the center bolt. Then remove the (4) hold down bolts that secure the fuel rail.
Most shops will recommend replacing all the injectors but I've had a couple vehicles where I replaced only the bad injector and haven't had a problem but it's basically up to you. Just remember to replace the orings with new ones.
Most shops will recommend replacing all the injectors but I've had a couple vehicles where I replaced only the bad injector and haven't had a problem but it's basically up to you. Just remember to replace the orings with new ones.
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Joined: Dec 2001
Posts: 22,436
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From: Louisville,Ky.
He probably got a #4 cyl. code from the balance test. OBD-I didn't specify cylinders like the OBD-II does.
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Lead Driver
Joined: Nov 2002
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From: Concord, NC
Only SEFI does the cylinder balance test (OBD-I will give a cylinder number for the balance test). A 90 truck is not SEFI, it is batch injection and cannot do a cylinder balance test nor can it pinpoint a cylinder (unless it's some super fancy scan tool).
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Lead Driver
Joined: Nov 2002
Posts: 9,555
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From: Concord, NC
I'm not sure exactly what the output of the code scanner was. You can do your own cylinder balance test by pulling the connector off of one injector at a time and note the rpm change. If the rpm drops less for one cylinder than the rest, that injector isn't injecting enough fuel.