Challenger Posted August 10, 2010 Share Posted August 10, 2010 (edited) Engine: l28et from 81 ZX. Car: 78 280z EMS: MS2, fuel and spark using stock harness As the title said, the 81 l28et has a cylinder head temperature sensor along with two signals coming from the thermostat. One I assume for the gauge, not sure on the other. Now my 78 280z is getting megasquirt and I am using the 81 l28et thermostat. The wiring harness on the 78 has 5 wires going to the thermostat, 2 plugs and 1 single wire. My question is should I use the 78 thermostat? Is there a way to use the l28et's thermostat and hook everything up to the gauge correctly? Would I really only need to use one of the sensors on the l28et thermostat for the gauge and then use the new CHTS as a signal for megasquirt? Or? Heres the guide Im using for the megasquirt install. http://forums.hybridz.org/index.php?showtopic=48292 Also let me know if more info is needed. I can take pictures of both thermostats or of the wiring harness on the 78. Thanks, I couldnt do this without HybridZ! Edited August 10, 2010 by Challenger Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted August 10, 2010 Share Posted August 10, 2010 (edited) Do you know if the '78 280Z and '81 280ZX use the same model dash temp guage? That is the only thing I can think if that would make a differnce in which housing to use. The two sensors/signals you'll need are CLT for MS and the existing thermal sensor if you want the dash guage to work. I'd probably go with the '78 housing just to eliminate the potential problem of differing guage styles. I recently did a fuel only MS install using the existing harnes on a '75. Before the install I read the thread you linked. With respect to the author of that thread, I found it was easier to sit down with the wiring diagram from the EFI bible and do it myself. The wires in the EFI harness are numbered which helps a lot. And if I can be of any assistance to you, feel free to PM. Edited August 10, 2010 by tennesseejed Quote Link to comment Share on other sites More sharing options...
aarang Posted August 10, 2010 Share Posted August 10, 2010 The sensor with the 'nub' on it is for the temp gauge. You should be able to use the ZXT sensor with your Z gauge. The other sensor with the wire pigtail is actually a switch for the injector fan. You don't need to use that one. Quote Link to comment Share on other sites More sharing options...
Challenger Posted August 10, 2010 Author Share Posted August 10, 2010 (edited) Ok, yeah the ZX has two "nubs", so one is for the gauge, one for the fan. CHTS pigtail is for the engine. Now on the Z thermostat there are two pigtail plugs and a single nub, which is which? Im trying to download the FSM from xenons30.com but I dont have winRAR... Ill look at the wire numbers going to the two pigtails when I get home maybe someone can look it up for me. I also need to figure out which wire went to the single nub on the thermostat. Edited August 10, 2010 by Challenger Quote Link to comment Share on other sites More sharing options...
Challenger Posted August 10, 2010 Author Share Posted August 10, 2010 Ok, just switched out the thermostats. As I mentioned, one of the pigtail connectors is broken off so I need to figure out what they are both used for. If anyone has a FSM for a 78 it might mention it. Anyways could someone with a 78 take a picture of their thermostat? Im trying to find where the single nub connecter comes from in the harness. Stupid me for not marking things well enough. Quote Link to comment Share on other sites More sharing options...
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