EFI questions
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New User
Joined: Dec 2007
Posts: 22
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From: McKinleyville
EFI questions
EFI swap. I just got my HO SD EFI on my 302 and I need to know how many O2 sensors do i need. i have long tube headers into single exhaust. also where can I buy the O2 wiring harness that plugs into the main computer harness. thanks for the help
Postmaster
Joined: Dec 2002
Posts: 3,594
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From: Southern Oregon USA
The HO uses 2 O2 sensors. One in each manifold. Ideally, you want them as close to the stock location as possible to keep the computer happy. I mounted mine in the header collectors and have noticed no adverse affects.
Ford Racing used to sell an O2 harness, but I'm not sure if they would fit all of the HO harnesses 86-93, or just the MAF. I'm not sure if there is a difference. Never compared them. You may be able to search wrecking yards for a used one if you have the resources.
There is also RJM that makes complete harnesses. They may be able to put something together for you.
Jason
Ford Racing used to sell an O2 harness, but I'm not sure if they would fit all of the HO harnesses 86-93, or just the MAF. I'm not sure if there is a difference. Never compared them. You may be able to search wrecking yards for a used one if you have the resources.
There is also RJM that makes complete harnesses. They may be able to put something together for you.
Jason
Tuned
Joined: Aug 2002
Posts: 476
Likes: 1
From: Greatest state on earth
I thought the O2 sensor plugged directly in to the main harnass. If you have the other sensors and injectors already wired in, the plugs should be there. The O2 sensors come with the wires and plugs, in several different lengths that should accomodate just about any conversion.
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New User
Joined: Dec 2007
Posts: 22
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From: McKinleyville
nope, they do plug right in. but the guy i bought it from unplugged it. I just made my own harness.
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New User
Joined: Dec 2007
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From: McKinleyville
ok so new problem. I have everything wired in and Im not getting power to my fuel pump. I have power to the eec relay but no power to the fuel pump relay. If Im right the red wire coming from the green connector near the computer, is the power to the coil side of the relay and the tan/light green wires are the ground. so then i attach 12v hot wire to the switched side and run the last wire to the fuel pump power. so when the key is turned of then the computer grounds the fuel pump relay through the two tan/light green wires causing the switch to contact and run the 12 v through to the fuel pump. but I am not getting any power. HELPPPPP. lol thanks
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