ZHoob2004 Posted June 6, 2016 Share Posted June 6, 2016 I'm swapping a 280zx (N/A) motor into my 280z, can I use the newer 280zx harness/ecu without too much trouble? My harness on the stock motor is a bit butchered from previous owners. Anyone know anything I need to watch out for? Quote Link to comment Share on other sites More sharing options...
ZHoob2004 Posted June 10, 2016 Author Share Posted June 10, 2016 So I haven't had a chance to look close at the harness for about a week, but am I incorrect in thinking the main difference is the connection to the combination switch (or lack thereof) and the fusible link connections? Unfortunately I can't find any decent pictures of a complete zx harness to compare to. Quote Link to comment Share on other sites More sharing options...
JSM Posted June 10, 2016 Share Posted June 10, 2016 Yes you are right in your assumptions. Folks swap the 280zxt harness and ECU all the time. They have for years. Keep searching and reading. Quote Link to comment Share on other sites More sharing options...
afbrian13 Posted June 15, 2016 Share Posted June 15, 2016 It's super easy. I have a zx na motor in my 76 right now. Didn't even disconnect the harness from the motor when I pulled it. 2 wires go to hot power and run the ecu plug through the firewall. I could double check mine tomorrow if your still having troubles finding the info. Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 15, 2016 Share Posted June 15, 2016 They changed the pins at the ECU in 1979. Somewhere out there is an explicit instruction to never connect a ZX ECU to a Z harness, or vice-versa. You can use the compete EFI system on an earlier engine. But the harness alone won't transplant. Maybe the ECU plus harness, plus some modifications to the fuel pump control. But not a direct harness swap. Use the 1980 EFI Guide if you want to study the differences. http://www.xenonzcar.com/s130/other.php Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 15, 2016 Share Posted June 15, 2016 Later ZX's use an O2 sensor also. Not sure what the ECU does if there's no signal at all. Quote Link to comment Share on other sites More sharing options...
afbrian13 Posted June 17, 2016 Share Posted June 17, 2016 Oh yeah sorry. I'm using the zx ecu, mass air, etc. My motor would run on a stand by itself with a battery, fuel pump and gas can. Didn't splice into the stock harness at all. Quote Link to comment Share on other sites More sharing options...
ZHoob2004 Posted July 31, 2016 Author Share Posted July 31, 2016 I guess it's time I give an update. I found the easiest way to get it working was to grab a 280zx fusible link block and hook the harness up through that. I'd like to say that it started right up after that, but it turns out my 280zx ecu was bad and half the injectors were always on, half were always off. Swapped the stock 280z harness/ecu back on and it started right up. Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 31, 2016 Share Posted July 31, 2016 turns out my 280zx ecu was bad and half the injectors were always on, half were always off. Or....the wiring wasn't right. Quote Link to comment Share on other sites More sharing options...
ZHoob2004 Posted August 3, 2016 Author Share Posted August 3, 2016 Or....the wiring wasn't right. Entirely possible. Main symptom that caused me to blame the ECU was that the rear 3 injectors were powered as long as battery power and the ecu were connected to the system. Other contributor to that was the associate I got the engine from said the engine last ran only on starting fluid and he didn't diagnose it, and that fits with what I experienced (essentially running on the cold start injector). Of course, I was not able to test another ECU or harness, so either could be at fault along with my wiring, which was ~6 connections, I'm pretty sure all of which go to +12v (and the coil connection) Quote Link to comment Share on other sites More sharing options...
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