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Hello,
I'm in the process of swapping from a 4.9L to 5.8L in my '91 F150.
I was able to scavenge a '91 F150 engine wiring harness from a junkyard.
I have a question about two of the plugs.
1. This plug appears to go to the AIR tubes on the back of the engine which I am not running since I am using GT40 heads.
If I leave this unplugged will it cause a CEL? If so, is there a way to fool the computer?
2. This plug comes out near the 4 main plugs that connect the engine wiring harness to the chassis wiring. I have no idea what this one goes to. Can anyone help me out? Could someone possibly snap a picture of where this plug hooks up on your truck?
I'll see what I can come up with in the way of pics, but while you've got such good access to them post up the wire colors too.
I'm sure there are members here that can look at a plug and see the orientation and know right away what it's for, but the wire colors can still confirm things.
Perfect! That should help someone get you the answer I'm sure.
I'll look in my '93 diagrams even though yours is a '91 because there's still a good chance that the colors remained the same for whatever their function was.
2) Looks like a fuel injector connector. With those long wires maybe A/C compressor? If the harness is were it is supposed to go...what has a plug like that that it will reach?
So, if 1 is for the knock sensor, I should be able to leave it disconnected for my 5.8L, correct?
I agree, 2 does look like a fuel injector connect, but it's not... All of the injectors are already plugged in and it's in the wrong place on the harness for an injector... hence my confusion.
With those long wires maybe A/C compressor? If the harness is were it is supposed to go...what has a plug like that that it will reach?
A/C and injectors are already hooked up. I've looked in the truck for something in that area with a plug that looks like that... still haven't found anything. That's why I was hoping someone could snap a picture for me.
You may be onto something with that. My truck doesn't have a switch on the power steering line, but I think some do.
I bought this wiring harness from an online junkyard, so I don't know if the donor truck did or not.
Can someone please check their truck to see if they have this connector, and what it's plugged into?
If you can't snap a pic that's ok. I just need some verification about where it goes.
Also, if you find that your truck doesn't have that plug, that could be useful info too... Maybe I don't need it and can just zip tie it out of sight.
Thank you so much! That is exactly what I needed to know.
Since this is going on a 5.8L I shouldn't need either one. I'll just zip-tie them neatly out of the way.
