LowCarbZ Posted September 1, 2010 Share Posted September 1, 2010 I own a 1974 early 260Z. The car generally runs great and hasn't given me a whole lot of unforeseen trouble. However, at the moment i'm stumped. Today on my lunch break I pulled in the driveway, shut the car off and it stayed running and didn't skip a beat as though I hadn't done a thing. I could lock the steering wheel and remove the key, the car would remain running. The only way I could get it to quit was if I snuffed it out with fuel using the manual choke. So logically I removed the cover around the steering column and started the car again. Even after disconnecting the ignition switch it would STILL remain running?!?! So I think this rules out the keyed switch being the problem unless there's something i'm missing here? Are there any "go to" fixes that have been known to cause this problem with Z's in the past? Other than that i'm just going to start chasing wires and looking for shorts after work today. But I can't figure out how it's still getting power if the ignition switch is out of the equation. Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 1, 2010 Share Posted September 1, 2010 Check alternator, do you have an external or internal voltage regulator? I do not remember the correct name for whats going on, but I think it's called "looping" Anyway this happened to me during my turbo swap and when I interchanged the external regulated alt for an internal one and did not add on a diode to the wiring. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 1, 2010 Author Share Posted September 1, 2010 ^ Thanks I will look into that. The only thing I can think is a short or possibly a relay that isn't working properly and won't kill the power? I'm just looking for suggestions and locations of components on the car that could be the cluprit. I think un-plugging the keyed ignition is a good indication that it is not the problem. That should've killed the engine if it were. Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 1, 2010 Share Posted September 1, 2010 My theory is something is keeping the constant cycle "ON" and prevent the break in the 12v circuit Quote Link to comment Share on other sites More sharing options...
GLSHLE Posted September 1, 2010 Share Posted September 1, 2010 (edited) I take it that if you kill it, You can clutch it and it will run? Killing it doesn't break the circuit? Edited September 1, 2010 by GLSHLE Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 1, 2010 Author Share Posted September 1, 2010 If I kill it i can still drive the car with the key in the off position. What components could be keeping the 12v circuit in a closed position? I am assuming a relay is to blame as I mentioned or your alternator regulator theory seems like a good one. The only reason I doubt the alternator is that I recall yesterday I went out to get in my car and the radio was on. I though maybe the key cylinder had let me remove the key while still slightly in the ACC position, however I ALWAYS lock the steering wheel. It's a habit. So something is keeping constant 12V power engaged when the car is completely turned off. Quote Link to comment Share on other sites More sharing options...
GLSHLE Posted September 1, 2010 Share Posted September 1, 2010 I think it's a short in the wiring. I'd start with the steering column, hazards, brake lights have power. Just look for rubs and melts. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 2, 2010 Author Share Posted September 2, 2010 No obvious rubs or melts. I did however check the relays in the passenger compartment and all seemed well. With the car off I checked the connections at the alternator. The plastic plug connector in the back of it when pulled out with the car completely shut off and the key in the off position let out about a 1" arc between the connector and the point where it is usually plugged in. This lead me to what Daphur280 was talking about where the external regulator may be to blame keeping constant draw to the alternator which keeps the charge cycle in a loop. I found the following information online while searching tonight. I'm going to see if I can find another regulator in my parts collection and barring that i'll just upgrade the alternator to a newer internal regulator ZX design or try the diode fix if need be. http://www.zcarcreations.com/howto/voltreg.htm Thanks for the help so far. I'll post any info I come accross for others' future reference. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 14, 2010 Author Share Posted September 14, 2010 Had to wait a few days for the Alternator to come in... Anyway, I did the following: - Bolted in the alternator - Added the Diode to the "T" connector to allow the car to shut off with the key - Jumped the YELLOW and WHITE wire after removing the Regulator on the inner fender. - Jumped the BLACK /W WHITE LINE wire and the WHITE /W BLACK LINE wires - Hooked up the battery cable and the ground to the alternator. I fired the car up. It started and ran fine and actually for the first time with the key in the "ON" position I could actually hear the factory electric secondary fuel pump working in the back of the car, it never had. The car ran fine, alternator is charging and the car shuts off with the key. ONE PROBLEM! The heater controls (fan etc.) and the radio are dead. Everything else works on the car, the wipers, the lights. But the radio and heater controls do not. What am I missing here? Quote Link to comment Share on other sites More sharing options...
19762802+2 Posted September 14, 2010 Share Posted September 14, 2010 Did you check your fuses? some might have gone out during the swap. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 14, 2010 Author Share Posted September 14, 2010 Did you check your fuses? some might have gone out during the swap. I checked all of them with a meter and they're fine. I followed the instructions from some links online that I came accross for the swap and wire jumpers. I'm just wondering what i've done wrong. I would assume those wires I jumped run power back through the relays on the passenger side footwell. I no longer hear the relays clicking inside the car when the key is in the "ON" position like I used to. Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 15, 2010 Share Posted September 15, 2010 I checked all of them with a meter and they're fine. I followed the instructions from some links online that I came accross for the swap and wire jumpers. I'm just wondering what i've done wrong. I would assume those wires I jumped run power back through the relays on the passenger side footwell. I no longer hear the relays clicking inside the car when the key is in the "ON" position like I used to. You know, now that I think about it, my heater didn't work after I installed the 60amp alternator with the MSA Diode connector. I didn't even think to see that before, mostly because I installed it during the summer so the heater would have never been on. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 15, 2010 Author Share Posted September 15, 2010 You know, now that I think about it, my heater didn't work after I installed the 60amp alternator with the MSA Diode connector. I didn't even think to see that before, mostly because I installed it during the summer so the heater would have never been on. Did you manage to resolve this ever? We're coming up on the cold season here in Canukistan and it will be pretty important to get the fog off the windshield and keep the girly's toes warm. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 16, 2010 Author Share Posted September 16, 2010 Spent some time fiddling under the dash last night, checked every connection for the radio/heater and got it working. Totally un-related issue to the wiring of the alternator. The alternator swap with the diode worked great on the 74 260Z (however, with a couple of owners and 35 years of history who knows if my wiring matches a factory 260Z entirely). More amperage, brighter lights, my electric fuel pump started working again as well. Thanks for the input on this guys, back on the road. If anyone ever has questions doing this feel free to PM. I'm not on the forum all that much but I am around. Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 16, 2010 Share Posted September 16, 2010 Did you manage to resolve this ever? We're coming up on the cold season here in Canukistan and it will be pretty important to get the fog off the windshield and keep the girly's toes warm. not yet, I'll probably have a look this weekend, because cold rainy season is here Quote Link to comment Share on other sites More sharing options...
jacob80 Posted September 16, 2010 Share Posted September 16, 2010 I'm having a similar issue, but I believe I have a bad starter solenoid. If I turned the key to "off", the car would stay running and the starter gear would smack the flywheel and grind, but only for an instant when you hit the "off" position. Then, I would turn it back to "on" (keep in mind, the car is running this whole time) and it would do the same. I turned it back to "off" and the car finally shut down, but I heard a motor running and saw smoke from the passenger side. I jumped out of the car and the starter gear was spinning, but the gear wasn't poking out to engage the flywheel (gear reduction starter). Pulled the negative off and it stopped. Smacked the solenoid a couple times and put the negative back on the battery and it went away, but now the starter won't even click (assuming a bad solenoid). Hopefully I just have a bad starter, but I highly doubt it. Sigh. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 27, 2010 Author Share Posted September 27, 2010 (edited) ^ Any luck with your car Jacob? I am not out of the woods on this one yet. The new alternator is working great. However, went for a long drive yesterday and when I stopped along the drive for a break and the car shut off but the radio stayed on and the fuel pump kept running. Odd. Only way to turn them off was to disconnect the battery or the relays under the passenger side dash in the footwell. Later I stopped for dinner and shut the car off and the same thing, pump and radio stayed on. So I disconnected the "T" connector on the back of the alternator. This killed the power to the radio/pump and I figured "ok, the diode I installed is no longer any good i'll have to replace it to stop the power from looping". So I drove another 2 hours to get home. Got there, pull in the driveway and the car wouldn't shut off with the key. Fine, i'll just disconnect the problematic "T" connection with the in-line diode and replace it this week. After un-plugging it the car kept running. I was very confused by this. So I grabbed a glove, and pulled the coil wire to kill the engine. The pump and radio kept running until I disconnected the battery. I am officially stumped as to how the car can keep running and what's keeping the accessories powered? Looks like i've got a lot of wiring to follow ahead of me... Any suggestions? The car ran fine after I did the alternator swap but i'm thinking that's just a fluke. Edited September 27, 2010 by LowCarbZ Quote Link to comment Share on other sites More sharing options...
19762802+2 Posted September 27, 2010 Share Posted September 27, 2010 Maybe its time to name your car Christine and paint it red and white. I'm betting you have a wiring issue with a relay in the car somewhere or a relay is going bad. Did you remove the voltage regulator from the car when you did the alternator swap? Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted September 28, 2010 Author Share Posted September 28, 2010 Did you remove the voltage regulator from the car when you did the alternator swap? Lol @ the Christine comment. Yeah, I removed it and wired the jumpers up correctly, that all works great. I can't figure out how the car is getting power and remaining running if I un-plug that "T" connection??? I thought that is how the car would stay running if you didn't install a diode is through that wiring? Quote Link to comment Share on other sites More sharing options...
stav2201 Posted October 4, 2010 Share Posted October 4, 2010 Please, if anyone finds out the problem to this let me know too, my car just started doing this a couple days ago Quote Link to comment Share on other sites More sharing options...
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