himself Posted June 20, 2007 Share Posted June 20, 2007 I'm sure someone has posted the info but I cannot find it about what this wiring schematic I got with the megasquirt means. I've got a '75 280z with an '82 zxt motor in it and just bought the ms1 with the lc-1 and 12' wiring harness from diyautotune.com but the wiring schematic they give with the kit is not like any schematic I've ever seen. Can anyone explain it it detail? Where do the last 2 injectors hook up? what do the numbers on the relays mean? where do the arrows on the injector wires go to? Anyone have a really good link for installing the ms on 82 zxt stock engines? Quote Link to comment Share on other sites More sharing options...
spacecase70 Posted June 21, 2007 Share Posted June 21, 2007 http://forums.hybridz.org/showthread.php?t=88246 Quote Link to comment Share on other sites More sharing options...
himself Posted June 21, 2007 Author Share Posted June 21, 2007 I've already read this one which was not much help. I do not have a relay board, am not using any GM parts and do not have the MSnS version. On the wiring schematics I have been shipped they have 2 wires controlling all 6 injectors which makes no sense to me; how can each wire tell which injector to fire if it is talking to 3 at the same time? I've figured that the numbers on ther relays are actually embossed on the relay itself where the connections are made but they do not tell me what type and manufacturer the relays are. Mine do not correspond to their schems, anyone know which they are talking about? Ignore the arrows question, it is supposed to mean adding more injectors. It is a one type fits all schematic which sux. Quote Link to comment Share on other sites More sharing options...
spacecase70 Posted June 21, 2007 Share Posted June 21, 2007 ok now i know what you are talking about it is called a batch fire and that is the way the z works, it fires all 6 at the same time, what you do is connect it the way it shows and you will have 3 on injector cir. 1 and 3 on inj.cir. 2 it works really well and it keeps the injector driver's from overheating Quote Link to comment Share on other sites More sharing options...
spacecase70 Posted June 21, 2007 Share Posted June 21, 2007 as far as the relays go they are just standard bosche relays Quote Link to comment Share on other sites More sharing options...
himself Posted June 21, 2007 Author Share Posted June 21, 2007 Ah ok, I did not know they worked that way, thank you. I did find out what the rekays they mention are expect that they are no longer in production. So do the bosch replacements also have the same set of 4 numbers listed on each connection to match what the schems say? Have a part number to go with them as well? Quote Link to comment Share on other sites More sharing options...
himself Posted June 21, 2007 Author Share Posted June 21, 2007 found the relays, though not made by bosch, they have the required numbers. Quote Link to comment Share on other sites More sharing options...
himself Posted June 21, 2007 Author Share Posted June 21, 2007 Thx for the pm spacecase70, just noticed it. If I get into a real bind I may give you a call. Another question about the wiring though; on the diagram it has listed that the IAC has 4 wires and the dizzy only 2 but upon pulling the old harness off the car the dizzy has 4 and looks a lot like the IAC in the diagram. Any help here? Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted June 21, 2007 Share Posted June 21, 2007 The IAC shown in the diagram is a GM-style stepper IAC and not present on Z-cars (except, of course, for the ones that have GM powertrains swapped in!). The generic diagram does not show specific connections for each car - it's patterned after the wiring seen on many 1970s era cars with a VR type distributor trigger. Which is why the distributor doesn't match the Z's. This article explains the distributor wire colors; the one marked "not used" is for a second distributor trigger with a ring of 360 slots that Megasquirt has no need for. Quote Link to comment Share on other sites More sharing options...
Slow_Old_Car Posted June 21, 2007 Share Posted June 21, 2007 http://forums.hybridz.org/showthread.php?t=102244 Quote Link to comment Share on other sites More sharing options...
himself Posted June 23, 2007 Author Share Posted June 23, 2007 Thank you for the explanations. Another question though, I was notified I would need a new tps switch and that a new model nissan 240sx' switch would be interchangable for the 280zx's and cost less from a junkyard. I got the switch and it slides in place but the mounting bracket on the 240sx is smaller than the 280zx's bracket. For those that did this mod, how did you mount it? 280zx on the left, 240sx on the right. Notice the width of the mounting plate. Quote Link to comment Share on other sites More sharing options...
himself Posted June 23, 2007 Author Share Posted June 23, 2007 I've hit another wall as well. I had asked before if the MS unit replaces the ECU and was told it does but my gauges all run through the ECU where as on the MS diagram they have no wires going to the gauges. Am I going to have to use both the MS and the ECU units? Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted June 25, 2007 Share Posted June 25, 2007 on a 75 the gauges are wired separate from efi wiring-you need to track your wiring down to memorize its functions.on my 77 there is a 5 wire connector that i used to get the key+ signal and the fuel pump is on that connector.i replaced all nissan oem efi wiring with new homemade harness and new plugs for injectors and sensors.all connections soldered and shrink tubed.the connector with key+ is located under steering column-it tied into oem ecm.the 240sx tps-i tore apart an oem 280z tps and made an adaptor plate from the back plate-i drilled and bolted the 240sx tps to the back plate of the 280z tps.i got a pigtail for the connector from pick&pull.my ms and relay box are located on the bulkhead behind the seats-less water there and easy access . Quote Link to comment Share on other sites More sharing options...
naviathan Posted July 13, 2007 Share Posted July 13, 2007 on a 75 the gauges are wired separate from efi wiring-you need to track your wiring down to memorize its functions.on my 77 there is a 5 wire connector that i used to get the key+ signal and the fuel pump is on that connector.i replaced all nissan oem efi wiring with new homemade harness and new plugs for injectors and sensors.all connections soldered and shrink tubed.the connector with key+ is located under steering column-it tied into oem ecm.the 240sx tps-i tore apart an oem 280z tps and made an adaptor plate from the back plate-i drilled and bolted the 240sx tps to the back plate of the 280z tps.i got a pigtail for the connector from pick&pull.my ms and relay box are located on the bulkhead behind the seats-less water there and easy access . Randy, Thanks for that bit of info on using an old 280Z TPS for a back plate, I was just tossing the idea of welding longer tabs on, but though it a bad idea as it might damage the potentiometer. I like your route better. Quote Link to comment Share on other sites More sharing options...
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