Lockjaw Posted October 19, 2002 Share Posted October 19, 2002 Hey guys. My 260Z will start just fine, but it won't turn off with the key. It wouldn't before I replaced the engine compartment harness, and it won't after either, except I fixed the not starting problem. Any idea's? Ignition switch perhaps? I have everything hooked up correctly as best I can tell. Electrical is just not my thing. Thanks Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted October 19, 2002 Share Posted October 19, 2002 This problem seems familiar. I put an internally regulated 280z alternator in my 240 years ago and had the same problem. What happened was the alternator was feeding back power through the field curcuit when I shut the car off - so it would keep running. If you stalled the engine, there was no power anywhere. I don't know what alt you have on your 260. I solved the problem with a field relay that cut off the field when you shut the ign off. An easy way to check if this is the problem is to unplug the field connector on the alt(small white plug) when the car is running with the ign off. If the car stalls - problem found. Other than that, it could be the ign switch. (shrug) Other electrical gurus?? Hope this helps - Doug Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted October 19, 2002 Share Posted October 19, 2002 Another thought - If your alt has an external regulator on the fender still - It could be screwed up or the wiring to it could be screwed. This could feed power back through the ign circuit Doug Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted October 20, 2002 Share Posted October 20, 2002 Are you running an electric fan??? When I installed mine I didn't use a relay and when I turned the key off it kept going because the fans rotation had enough juice to power the ign. I felt stupid that day for not using a relay like I knew I should!!! Quote Link to comment Share on other sites More sharing options...
v8dats Posted October 20, 2002 Share Posted October 20, 2002 i replaced my alt with one from an 83zxt(same as the engine)and it wouldnt shut off.went back with the old 74 and it was fixed. thats all i know Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 20, 2002 Author Share Posted October 20, 2002 NO electric fan, using a voltage regulator, as far as I know, the alternator is the right one. When I bought the car, the morons who worked on it had wired up a switch and hot wired it essentially, so I am trying to fix that, which is the main reason for the harness swap. When I pull the field deal out of the back of the alternator, the car does shut off. I am getting a replacement switch, and it should be here in the morning. the continuity was not working when the switch was in the start position, but it checked out fine in every other. I hate electrical work. Now if I can get the brake lights working, and the turn signals, I will be in shape. Got hazzards on passenger side only. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted October 20, 2002 Share Posted October 20, 2002 Oh No - Another wiring harness screwed up by a previous owner The worst is when they screw the headlight wiring. One power wire/switched grounds do it to most backyard mechanics. Sounds like you have a problem in the voltage reg or wiring to it. I have seen some jobber v regs with the wiring messed up right out of the box. I'm at work right now and don't have wiring diagrams (I have a 280zx manual with me but no early Z) so I can't be much use to you. Sounds like you have it narrowed down though. Hope some of the gurus can step in with some wire colors to check. Tony? Good Luck - Doug Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 20, 2002 Author Share Posted October 20, 2002 Switch is in. I did a check for power on the field wires, and when the switch is off, I have power to the field one, when it is on, I have power to one but not the other. I have no power to the coil when the switch is off either, as long as the car is not running,when switch off and car still running, the coil has power. If the coil has power, then I guess I could cure that but putting a relay in line on the power line, and that would solve that issue. I bet it is one wire somewhere that is doing me in. Yeah it has some ghetto wiring done to it, which I replaced with the engine harness. It is pretty hard for someone to monkey with the harness in the dash, so I feel safe about that, but the tail section I haven't gotten into yet. Still haven't figured out the brake lights, turn signals, or hazzards. Replaced both hazzard and turn signal things, still no change. Then I swapped the combinations switches, and I have brake lights. Swapped the hazzard switch, and now I have turn signals, but no hazzards. So if someone can just tell me how to get the freakin thing to turn off with the key, I should be operational, at least legally. Man I hate wiring. It would help if I could read what all the stuff and symbols were. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted October 20, 2002 Share Posted October 20, 2002 you can always stick your finger in the dizzy cap Quote Link to comment Share on other sites More sharing options...
rags Posted October 21, 2002 Share Posted October 21, 2002 You have to put a diode in series on the wire that goes to the "L" terminal on the back of the alternator. The "L" terminal is the bottom contact on the "T" shaped connector. You have to connect the cathode of the diode (identified by a stripe on that end of the diode) to the "L" terminal and the anode (other end of the diode) to the wire that previously went to the "L" terminal. In my case (71 240Z) this was a white with black stripe wire. This prevents the "L" terminal current from feeding back into the ignition circuit when the key is turned off. I used a 1N5400. The diode costs about a quarter so it's worth a shot. Joe Quote Link to comment Share on other sites More sharing options...
Lewis Maudlin Posted October 21, 2002 Share Posted October 21, 2002 I HAD THE EXACT SAME PROBLEM!!! My distributor was getting feedback from a relay located just left of my left foot. There was a horn relay and another relay located there. I disconnect both of them and that solved the problem. Check it out. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 21, 2002 Author Share Posted October 21, 2002 Originally posted by yo2001:you can always stick your finger in the dizzy cap Yeah that would probably shut the car off and feel good in the process. I suppose I could run a wire from the fuel pump relay to the field position to power up the alternator. The problem is I really don't want to cut into a harness that I just replaced, know what I mean? I guess I could pull the field connector out, and cut the one off my old harness and then wire it up with the relay and a ground. That would leave my harness intact. Plus I don't intend to keep the thing externally regulated, so I wonder if I swapped to an internally regulated alternator if that would fix anything. I seem to recall I had this problem when I went to an internally regulated alternator on my 240 until I found a good switched power source to power the thing up and turn it off. I need to put a 90 maxima alternator in there and be done with it. Anybody else with a suggestion or something else I can check? Quote Link to comment Share on other sites More sharing options...
rags Posted October 21, 2002 Share Posted October 21, 2002 If you go to the internally regulated alt your gonna need the diode. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 21, 2002 Author Share Posted October 21, 2002 Where do you get those? Why would a relay not work? Quote Link to comment Share on other sites More sharing options...
rags Posted October 21, 2002 Share Posted October 21, 2002 Got mine at Radio Shack. If you have trouble I can mail you one. I have others that are a different part number but will also work. The relay idea will work but it is more trouble than the diode fix. Joe Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted October 22, 2002 Share Posted October 22, 2002 hey lockjaw i did the same thing rags did and it worked for me.I have a zx alt on my 76z and i put in a few diodes to handle the current.So far i ahve had no probs with mine.I'd try that before a relay.As for the lites and stuff good luck if i lived closer to you i'd help you but you being a little ways away makes it hard for me to drive there Do you have the cd rom of the fsm for the 260's or 280's if not i can get you a copy, let me know. It is alot easier with a readable wire diagram.The other books suck for the wiring. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 22, 2002 Author Share Posted October 22, 2002 I have the paper factory manual, and it is pretty good. I am going to try the diode and see what happens. Wiring issue's sure are fun. NOT. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 22, 2002 Share Posted October 22, 2002 O.k. They call me Relay-Pete in some parts. Sorry, I'd not want the back-emf or sneak circuit currents to burn out a diode and leave me fixing it on the side of the road, etc. I wired a relay to solve this little problem. Relay contacts may arc, but I keep a spare VF40 relay (all I use) around just incase one goes bad. Maybe I'm paranoid, but smoking diodes aren't fun. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 22, 2002 Author Share Posted October 22, 2002 Originally posted by pparaska:Maybe I'm paranoid, but smoking diodes aren't fun. I will wrap mine in duct tape if it makes you feel better. I am just kidding so don't flame me. I know better. Pete that is actually a valid point I had not considered. I may relay it, but for now, I am going to try the diode just to see if it works. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted October 23, 2002 Share Posted October 23, 2002 well lockjaw i haven't blown mine yet and wiring is too fun I actually love the challlenge of it, if i could i would just fix car wiring probs all day i get a charge out of it(no pun intended) good luck and if you want a cd rom of the 280z email me i'll hook you up with it Quote Link to comment Share on other sites More sharing options...
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