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Im scratching my head with this zx efi


lowrider

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Ok, The plan was to take said 81 280zx donor car strip the ecu, and efi wiring from the car to be put onto a L26 that resides in my 260z. Lets start from the begining (This is going to be long winded). I have a set of 3 screw round top s.u. s currently on the car. The car drives good, is real smooth but the horrid cold nature of this beast gets under my skin! I have an 81 280zx donor car that i am taking the transmission out of to swap anyways so why not go ahead and convert the L26 to efi "while i was at it". Today i pulled the zx onto the lift anticipating that the wiring wouldnt be too difficult to strip from it. I guess i seriously misjudged my wiring skills. After reviewing the wiring schematics for about an hour, i start disassembly. It began with two plugs underneath the drivers side kick panel. The first was a single wire plug that had a yellow wire attached. I later determined with the help of my haynes manuel's wiring diagram to be my ignition switched 12v power source(when in the on position).

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Ok, i think i have that one figured out, on to the next connector. Now i have no idea what this connector even remotely goes to, this is where i start needing your guys' help. This connector is also located in the drivers kick panel. Its a two prong conector with a White/red wire and a Red/black wire. I have no idea what this is. Ive tested it with the ignition on, and no power. Ive tested with the vehicle turning over, and no power to either prongs both times.

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Ok, the rest of the wiring is straight forward untill i get to what i think is the ecu relay and a handful of wires leading back into the passenger side of the car. From what i can see the efi only uses one side of the fuseable link. Resulting in the Brown and Green wires having 12v constant. Correct me if i wrong, the Brown and Green wires should be the only wires that give the efi power right?

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And then there is what i believe to be the efi relay...

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Now the part that confuses me the most. Off of the loom that carries the wires across the engine bay there are four wires that combine to make a four pronged plug. Like i said before the one side of the plug goes to the main efi harness, the other side however snakes through the inner fender and into the tangle of wires that seem to accumalate in the passenger foot well area. I finally tracked down the fuel pump relay with the help of my haynes manuel which tells me the wire color code and what component it goes to. The fuel pump relay uses the blue/red and the green wires from the 4 prong plug the other two wires i have no idea where they go to. When i looked at anothe schemaic of the year models' efi diagram it claims to have 3 fuel pump relays? I could only find the one that had any wires in common with the efi harness.

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efi side--------body side

blue/yellow----black/white...I believe this to be the tach signal?

blue/green-----green...fuel pump relay

yellow/black---yellow...I have no idea what this wire does.

blue/red-------blue/red...fuel pump relay

 

After all that long winded post here is the summary:

-what does the two prong connector with the White/red and the Red/black striped wires go to?

-Are my guesses of the wires and their purposes' so far correct?

-Is there more than one efi relay on the car?

-What does the yellow wire go to?

-What does the black/white wire go to?

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100_1989.jpg

did some wiring research, and ran into a bunch of turbo examples. Looking over these threads i think ive figured out where all the wires on this plug go!

 

black/white...goes to a 12v switched to turn on the efi relay

green...fuel pump relay

yellow...As far as i can tell its not used

blue/red...fuel pump relay

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  • 1 month later...

I missed it originally, and my 'example' car is 8000 miles away right now. The haynes manual is helpful, but you really need the ZX FSM, and reading the wire map will tell you EXACTLY where each wire in each connector will go.

 

They call out the pins by number (say 204) and then you look it up on the wiring chart on the back, and you will see in a matrix 204 starts here, goes there. By following that you can find the wires in the chassis, and on the diagram. You can flip between wiring diagram and that matrix and follow any wire throughout the whole chassis end-to-end.

 

That's the easiest way I found to do it if you dont' already know the answers.

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  • 1 month later...

I know im bringing this back from the dead but i figured i would tell my findings for future reference.

The car has been on the road for roughly a month, instead of putting the efi on the L26, i rebuilt and put in the L28. So i finally did firgure out all the wiring eventualy!

 

The first connector in my original post turned out to be the tach signal input... found that out after i had the motor in and it wouldnt fire. lol

 

The two prong conector with a White/red wire and a Red/black wire, wasnt used.

 

Per my last post, the wiring for the 4 prong plug was correct!

 

Well thats all i have to report, that should take care of the basic wiring to swap the NA EFI wiring harness into the S30.

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