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wiring harness and ecu question


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First off im new to the forum. I just bought a 78 280 z with an L28et swap. the car is currently using the stock ecu and a spliced up wiring harness. it runs poorley as a result. Im trying to locate parts to complete the swap and bring the car back to life. my question is will a wiring harness from an automatic 280zx turbo work with the 5 speed thats curently in the car? ive located a 5 speed ecu from a 280 zx turbo so that should take care of the fuel managment. i just need to sort out the wiring. Thanks very much.

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The wiring harnesses should be the same. The differences are in the 81 year harness/car as they use a crank angle sensor instead of the module in the distributor (82-83)

 

The other difference is that the manual (5 speed) turbo ecu should have a rev limiter, as the automatic car will not.

 

so find the harness and you should be set

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The wiring harnesses should be the same. The differences are in the 81 year harness/car as they use a crank angle sensor instead of the module in the distributor (82-83)

 

The other difference is that the manual (5 speed) turbo ecu should have a rev limiter, as the automatic car will not.

 

so find the harness and you should be set

I just found out that the harness is form a non turbo 83 280zx. Will this still work with the new motor? Thanks for the prompt reply! I really appreaciate the help as Im new to z's.

Rick

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Others have done it. It will depend on your experience reading wiring diagrams from the three different cars involved. Can you take a picture of your distributor and coil? That will settle the question about CAS (crank angle sensor). You will most likely be better off getting an 82 or 83 turbo harness and following the guides on this site. Check the FAQ's section for how to do the swap. Also a word of caution, you might want to do basic troubleshooting on why it runs bad before assuming the harness is the problem. Also in you posts please be specific, which stock ecu, which afm, ect. Some people have done some pretty crazy things to cars over the years. Knowing what you are starting with will help others help you.

Edited by ctc
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Im pretty sure its running bad because its running the 78 non turbo ecu and large 83 turbo injectors. More info to come. thanks again.

 

 

Yeah I'd imagine that's exactly the case. Yeah people have spliced N/A harnesses to work with turbo applications, but for what its worth, and the opportunity cost of a decent 82-83 turbo harness well outweighs the work involved.

 

I'd do this:

 

since you have the turbo motor (and hopefully a turbo distributor, if not get one) find a nice 82-83 turbo harness, and a turbo (preferably manual) ecu, although an auto ecu will work just fine.

 

The only thing you need to figure out, is which turbo base motor you have, and like I said earlier, the 81 turbo harness is a little bit different than the 82-83 years.

 

Then again there's always megasquirt, or some other standalone ecu, but that's a bit more involved.

Edited by OldAndyAndTheSea
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WOW, you are pretty young to be working on z's. But you got the right parts catalog. lol.

 

All kidding aside, you don't have a CAS distributor or coil, so that means you what to cannibalize an 81 and use the crank fired CAS system. Or swap the distributor and distributor drive, but that means dropping the oil pump.

 

My advice, find a complete donor car and get the ecu, harness and ignition coil. Also needed to check the fuel pump to see if it is the turbo pump or not.

 

Search on the many L28ET swaps here and once you find the direction you want to go. Post back and we will help as best we can.

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"The other difference is that the manual (5 speed) turbo ecu should have a rev limiter, as the automatic car will not."

 

Any hard evidence this is the case? I've heard the opposite, and from what I've seen no firstgen ECU's had any sort of 'rev limiter' whatsoever. You will peg the tach if you brick the throttle.

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WOW, you are pretty young to be working on z's. But you got the right parts catalog. lol.

 

All kidding aside, you don't have a CAS distributor or coil, so that means you what to cannibalize an 81 and use the crank fired CAS system. Or swap the distributor and distributor drive, but that means dropping the oil pump.

 

My advice, find a complete donor car and get the ecu, harness and ignition coil. Also needed to check the fuel pump to see if it is the turbo pump or not.

 

Search on the many L28ET swaps here and once you find the direction you want to go. Post back and we will help as best we can.

So my distributor is not going to cut it. Can you tell if this is the right distributor that came with the engine or is it the dizzy from the old na l28? Cant i just source out an 82-83 dizzy with the CAS and use that? Thanks

Rick

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Your current distributor looks like the one from the 78. You can swp to the 83 distributor, but you need to change the distributor drive shaft as well. Search on the l28ET swaps and they will describe how to do it. You will need to pull the oil pump.

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I dont understand why I cannot just find the right distributor for the motor. Why the need to drop the oil pump? For example if the motor is an 83 then an 83 dizzy should bolt up no issues right. I gues Im missing something here. Is my motor a frankenstein (l28 bottom l28et head)? I searched lotsa swaps but found no info specific to my issue. So if my motor is running a 78 2850z dizzy then what does that mean? Does it mean the bottom end is indeed a na L28? Thanks very much.

Rick

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The block model number is cast in to the side of the block, just behind and below the driver's side motor mount. Yours should be an F54 block, but could be an N42. Even if it's an F54 though, you could have flat top pistons, not factory issue for the turbo motors.

 

The head number is between the 1 and 2 spark plug holes, on the bottom edge of the head. With the CHTS shown in one of your pictures, yours will probably be a P79, P90 or P90A. Those two numbers will tell you something. Apparently the turbo distributor has a different drive "gear" that's why you have to change the "quill" (? - I think that's the right word) from the oil pump.

 

Your pictures do show some hackiness so you could have a mix of parts. A fun puzzle.

Edited by NewZed
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The turbo distributor and the NA motors use different drive shafts. You have to match the drive shaft to the distributor.

 

OK, so picture #1 shows an NA distributor, an NA distributor drive (quill) and the oil pump. Reference the FSM for how this positions in the motor.

 

Picture #2 is the NA distributor drive shaft, the end closest to the camera goes into the distributor.

 

Picture # 3 shows the NA drive shaft on the right and a turbo on the left. See the splines on the turbo shaft? That is why when you swap to the turbo distributor you need to change both the distributor drive shaft as well.

 

To swap to the turbo distributor, you need both the distributor and the matching turbo drive shaft. The turbo drive shaft and distributor will fit in any L series engine.

 

You should also download the FSM for both the year of the motor and the year of the car.

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post-5825-079660500 1339346661_thumb.jpg

post-5825-015608500 1339346668_thumb.jpg

Edited by ctc
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Define easier, megasquirt still requires the distributor be changed. Any ecu will require custom wiring and then there is the tunining. For some of us tuning is not "easy".

 

What is the breakdown on your turbo setup? What distributor, ECU, ect?

 

Factory option is plug and play once you understand what parts you need.

Edited by ctc
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