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L28et Swap Wiring Confusion


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Ok, So I need some help with wiring.

I am swaping a 1981 l28et into a 1976 280z

I recently just found out that the wiring harness and ECU that I have is from an 1982; after checking the serial # on the computer and noticing that the wiring harness did not have a hook up for the dropping resistors. I have been having difficulty understanding the wiring diagrams for both the 1981/2 harness and the 1976 harness. I have been using the Bumble Z ( wiring torutrial as a reference but I am still confused. Most of what I have figured out is quite simple: the injectors, CAS, other sensors, but thats about it.




1. The Coil and Ignitor


This is my original coil. What can I remove from this harness what should I keep?

post-29317-0-28341900-1429587852_thumb.jpg post-29317-0-11758400-1429587946_thumb.jpg

This is my "new" coil I do not have the part of the harness that plugs into it but I have firgured out a way to make a plug for it I just need to know what goes to what. The pins on the ignitor are shaped like a T (a Black w/ whit wire and a Blue wire run to the ignitor from the coil) I cant figure what I should wire to this But I am pretty sure it has to do with the computers spark control.


2. Fuseable Links

I have both fuseable links right now for the old engine and the "new" In this picture I have them mounted next to each other. post-29317-0-18761000-1429588644_thumb.jpg

I understand from the Bumble Z tutorial the only wires I need are the green a brown wire on the "new" harness. I am a little uneasy about removing or cutting any of the wires that lead to the existing fusable links. (Do I need this to run my lights or fuel pump?)


3.  Ignition Harness

post-29317-0-45259400-1429588976_thumb.jpg post-29317-0-37382900-1429588996_thumb.jpg

This was pluged into what I belive is the ignition harness of the "new" ECU and the back end of this plug should somehow run to the ignitor/coil. In the bumble z tutorial he had a 6 prong plug, his one has 8.


4. Switched Power

In the tutorial there are a lot of things that need to be run to switched power what should I use? I think I have firgured out that the black w/ white wire that runs to the coil should be switched power but im not really sure.


I will really apreciate some input please dont tell me to search more, maybe at least point me in the right direction. I live in the Seattle area but my car is in lakewood (hour south of seattle). If there are any wiring gurus that can help me I would more than greatfull. Also I am a college student at Seattle University studying photography. i am willing to trade som automotive photography services for help with the wirring.


Side Note: I am really losing morale I already have had one of the turbo engines I was working on stolen that I bought for $1000, wich is a lot of money to a college student.


Thanks for all the help!!!

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Bunblebee's writeup is not really a tutorial, it's more of a primer to get you started.  You need to get in to the stock wiring and control system diagrams, and test the circuits to be sure that things are connected as you think they should be. 


Attached an example of the ignition circuit.




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A typical page in the FSM will show the simple diagram then a drawing of the wiring with connectors.  Shapes and everything.  Another sample.  Included a page number.


Can't go wrong at least taking one quick look at it.  You might get hooked.  It might be liberating.


You can also use a meter to see which wire ends are connected to each other.  Beware relays though.


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Hmm, well just off the bat you are going to have a little problem in the fact the 82/83 zx turbo have a trigger wheel in the distributor and I think the 81 has a toothed crank wheel (or it might be the other way around).


Unfortunately the thing is you are going to have to search more. Not necessarily just for what goes where, but how to find the wires you are looking for. Switched power can be easily found with a test light or a multimeter and the key in the on position. The wire should have 0 volts when key is off and 12-14 volts when key is on. Depending on what you are using the switched power for you have to make sure that it also stays on during cranking as well. Once you find it you can run a relay board using the switched power as a signal and run new wire to power whatever you need switched power for. If you have a high enough amperage relay you can split the output power and run a fuse box in-between and use the fuse box as a distribution block.


I believe the plug mismatch comes from the difference between the 81 and the 82 cars.


I'm in the area if you need help. Granted I am only familiar with the swap, so I would be doing the same thing you would be doing which is searching for wiring diagrams and comparing.

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Thanks NewZed I will try to compare both FSMs better. Seattlejester after doing some research I found that the crank angle sensor that is located on the crank for the 81 motor will work should work just fine with the 82 harness and ecu. If you want to go down to lakewood (I live in seattle but my car is in lakewood) this sunday and help out, I could give you a ride + free beer, no pressure or anything. 


I really appreciate all the input :)

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  • 2 weeks later...

The "new" coil and ignitor:  The "T" connector is for power and ECU signal.  Power comes from the Black/White you already have at your stock coil.  With the new coil, it'll power the Ignitor and then to the coil (+) with the wiring that's already there.  The Blue is output from the ignitor to the coil (-).  You need to add the Yellow from the ECU to the Ignitor to get the "signal to fire" and that's all you'll need...


That's also where your existing Blue from the stock coil harness will connect - it'll (re)connect the tach signal.  You need to disconnect the stock Electronic Ignition Module under the dash (at the very least, remove the Blue wire from the module and tape it off).  (on the '76, the Blue originates at the Ignition Module and "tees" off to both the coil (signal to fire) and through the resistor to the tach (tach signal.  If you remove the link to the stock Ignition Module it just becomes the Tach Signal from the "new" coil/ignitor...)


As for the fusable links, I do the same thing - use the 280ZX link block - and just tie it to the battery


Your research was correct - you can use the '82-'83 harness.  The CAS signal and wiring are the same.

Edited by cgsheen
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