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Item Posts    Sort Order

injection problem

New User
Posts: 1
Joined: 11/12
Posted: 11/23/12 06:30 PM

ok I have an 90 lx foxbody it came with a 302HO I replaced it with a 302 efi now car runs bad any help  

Post Reply
Posts: 166
Joined: 04/12
Posted: 11/23/12 07:57 PM

a few things....  that will probably straighten this out...

the 5.0HO and the 5.0EFI have DIFFERENT firing orders... not a HUGE problem... you are just going to need to switch the wire positions around...

a little harder is the slight difference in the fuel injector firing order... the 5.0HO is a sequential fuel injection motor...   the injectors are fired individually in the firing order... the 5.0EFI fires four injectors then the other 4 injectors...   so.. which computer did you install with the engine.. which wiring harness between the computer and the engine.. and which engine harness...  

Post Reply
Posts: 166
Joined: 04/12
Posted: 11/23/12 08:16 PM

the H.O firing order is 1-3-7-2-6-5-4-8  
the EFI  firing order is 1-5-4-2-6-3-7-8

this site says the best option is to swap the HO cam into the EFI motor...  then you can use the HO computer and the HO firing order without running into serious issues...

do you still have the OLD HO motor.. as these are roller cam motors.. so you can JUST SWAP them engine to engine and reuse the roller lifters after inspection...  roll the lifter on the inside of your wrist . make sure that you don't feel ANY ROUGHNESS..  if the OLD motor was contaminated with coolant.. or water in the oil.. and you need to use any of those lifters.. you will need to really take the internals out ONE LIFTER AT a time and take it completely apart.. cleaning it.. then using some thing like 0W-20 oil.. or 5W-20 oil if you can find a quart to lightly lube the parts prior to assembly..  finger prints on the internal parts are a bad idea...

there are other forum members who may chip in over the next few days...

HO 5.0 cams are available..    i am hoping the EFI 5.0 motor is a roller cam motor.. i don't recall what year they started 5.0EFI s with roller cams..  

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