Guest bigjim240z Posted May 25, 2003 Share Posted May 25, 2003 i have an 81 280zx n/a. i bought the car a month ago not running. it only was supposed to have a bad head gasket, well after getting that all fixed now im having efi trouble. i was getting no signal to the injetors, thus no fuel. i used a noid light on each injector plug and got no flash of the light while cranking. so i replaced the whole harness, ecu, relays , dropping resistors,and fuses with parts from a running 1981 280zx parts car. after all this work i still had the same problem! well i might have made a stupid mistake but i decided to rip out the whole system and go with somthing i know a little better. a few years ago i installed a 1977 280z harness and complete efi system in a 240z, so i decided why not do the same to the zx...i thought it would be a peice of cake. well after installing it all into the zx i have the same problem...lol..no signal to the injectors. the injectors are good so i dont think this is my problem. i have power to both sides of the injector plug when the key is on, but when i crank it the power shuts off, but returns when the key is backed off to the on position..i tought i was only supposed to have power on one side of the injector plugs not both, the zx harness only had power on one side. should i put the 81 harness back in and start trouble shooting the 81 zx system or leave the 77 system in?? im in serious need of some help here guys....thanks for any advice..jim Quote Link to comment Share on other sites More sharing options...
Guest bigjim240z Posted May 25, 2003 Share Posted May 25, 2003 no idea's? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted May 25, 2003 Share Posted May 25, 2003 The injector has power on both sides because the ECU pulls one side to ground to energize it. If it's not active, you see voltage on both sides. Sorry not much more insight to your problem. Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted May 25, 2003 Share Posted May 25, 2003 Not a Nissan efi expert. You mentioned that power goes away while cranking and returns when the key is returned to the on position. Could the problem be in your ignition switch? Quote Link to comment Share on other sites More sharing options...
Guest bigjim240z Posted May 25, 2003 Share Posted May 25, 2003 anythings possible since i dont know much about this car. i have never even had it started yet...i guess i need some one with a 77 to tell me if they have power to both sides when the key is in the on position, and what happens when they crank the motor? man im stumped on this, ive worked on alotta cars in my time but efi eletrical problems are not my specialty. thanks for the info, please keep it coming so i can get my zx running! Quote Link to comment Share on other sites More sharing options...
Guest bigjim240z Posted May 25, 2003 Share Posted May 25, 2003 well aftr a couple hours of getting nowhere i decided to go back to my original 81 harness that belongs in the car. i have the harness back in and am about to start trying to get an injector signal...i went to the junk yard and found an 81 zx so i grabbed the efi relays and a few sensors. im gona just trouble shoot this system. anyone have a 1981 harness diagram they can scan and email me?...i would just buy the book if i could find one local, but thats not gona happen today!..thanks jim Quote Link to comment Share on other sites More sharing options...
Guest livewire23 Posted May 26, 2003 Share Posted May 26, 2003 I'm thinking perhaps its something to do with your battery or something if you're not getting juice to the injectors while cranking? I know on newer cars usually all acc. shut off while cranking, so perhaps the injectors are wired up wrong? Quote Link to comment Share on other sites More sharing options...
80LS1T Posted May 26, 2003 Share Posted May 26, 2003 Have you checked all your ground wires? Like on the computer, wiring harness, etc? I had a problem like this on a 94' Geo Metro. It turned out that it was just a ground wire wasnt hooked up on the engine. If it ran before you did the headgasket and now it doesn't ...then I would check for bad ground wires. Guy Quote Link to comment Share on other sites More sharing options...
zxgts-4 Posted May 26, 2003 Share Posted May 26, 2003 Jim, is the car an auto? If so it could be an inhibitor switch, connection at the trans or relay. It hasn't blown a fusible link? Seems like you have disconnected everything else then reconnected it. Neil Quote Link to comment Share on other sites More sharing options...
Guest bigjim240z Posted May 26, 2003 Share Posted May 26, 2003 ok..yesterday i got pissed off and put the complete 81 system back in..i mean everything is back to the way it was. i also went by my local junk yard and grabbed some relays. i put them in along will cleaning all connections and sanding the ground straps to insude a good ground. well im now getting fuel. i put on a noid light to the injector plugs and it does flash. finally, too bad i really cant say 100% what it was..i wish i did this before ripping out the whole harness and having to reinstall it...lol..oh well..now i gotta yank off the timing cover, i can hear the timing chain slapping around.........but this is the way it goes owing a z that some one didnt take car of...one problem after the other till you got a new car...lol..thanks for all the help guys! Quote Link to comment Share on other sites More sharing options...
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