Good Morning: Project (August 1971 240Z production) is progressing. Floors repaired, brakes repaired, body work 95% done and almost ready for paint. It allowed me some time for the other issues. Primarily, the failure of the engine to start (ignition and fuel issues).

After the new carpeting was installed, I delved into the steering column, only to find the same old, same old; a previous owner had "been there." I determined the switch contact points on "start" were worn and I will replace the switch. We did hot wire the car to get it running previously, and it failed to continue running when the priming gas was used up. I drained the float bowls, left the plugs out of the bowls, removed the fuel line before the fuel pump, and ran the starter to clear the fuel lines of all previous gas; hooked up an auxiliary tank with two gallons of fresh gas to the fuel pump, and the engine runs fine. So what's the problem? Here goes......

When I got to the ignition switch, by removing the plastic column pieces, everything made sense, except for the two wires that were "disconnected" by a previous owner. They both go to something in the combo switch. Now, I could try all the devices controlled by the combo switch but the car is stripped down ready for paint; but would prefer to know what was disconnected and why, so I can put it all back together again and not have to take it apart or leave it apart until I get the car back together after paint. I have accessed quite a few wiring diagrams, but none focus specifically on the color wire relationship to each device. I am hoping someone here can tell me what each color wire is related to in the "combo" (smart) switch..... Both wires have a connector so you can tell what was pulled apart and they are different enough connectors to where you can tell there is a very high level of confidence as to which connects to which.... In the combo switch, there is a red wire and this red wire mates with a red wire running in the column area.... Also disconnected in the combo is a blue/white wire that mates with black yellow wire in the column...

Does anybody have an idea or a better wiring diagram that would tell what devices the red wire and the blue/white wire on a smart switch control?

Further.. I have read about draining the tank which I must now do. There is a plug, but I will need a replacement washer. Does anybody know the typical name or size of that washer? Further yet, is this drain plug easy enough to remove to where I can safely assume that it will come out without damaging the fuel tank. The last thing I want to do, is to be replacing a fuel tank. Would siphoning the gas out and leaving the plug alone be a better option?

Sorry to get so wordy, but the more facts, the better... and I have found on this car, that I have to go one step further than normal troubleshooting by first figuring out what previous owners have done; shortcuts if you will, and then put the car back to factory.... Thanks for your help.

 

This might help,
I need everyones input on this one (Combo and T/S switches)
Save yourself some grief, pull the tank and send it to a radiator shop to be boiled out. I drained all my Z tanks and re-installed the plug, np

 

Have you looked at the FSM at XenonS30?

Also, could you post a picture of the wires in question?

 

Sorry for the pathetic camera work but this is the best picture I have of the steering column wiring after I pulled apart the two pieces to take a look. If you look carefully you will see the two red wires disconnected.... and they do connect because of the kind of connection they use. The other disconnected wire is the blue/white wire next to the red one on top... look carefully and you will see that one too.... it should connect to the lower loose wire; again because of the connections used, and that lower loose wire is either black white or black yellow... hard to tell because the white is faded??? .... I did do some more looking and had to get a magnifying glass out to look at the wiring diagrams of these two areas... It appears that the heavier red wires are the headlights and the blue white I see as the windshield wipers on the combo switch circuits... I have no idea why the previous owner(s) disconnected them. I am currently waiting for the combo switch to arrive to install that and then I will install that and probably connect the two wires again... I have installed a battery cut off to disconnect the battery in a hurry if there is a problem... I did find the ignition switch problem as several suggested it would be... notorious??? And the book has two steps to replace it.... one screw, and get the wires moved to the correct spade terminals.... nothing more on that... should be a piece of cake?

Also ordered an oil pressure sending unit... and a new stereo as well. Doing the usual mods on the console to make it look new again... lots of experience with that.... Interior is almost done now, and cosmetic work progresses before paint. It won't be long now.

Gas tank drained with no problems and gas looked good... not discolored nor sediment or rust or anything; just old and blew the gas line back to the tank as well so new gas will go in.... auxiliary tank still hooked up to run the car and it works really well... but it would be hard to have that tank sit on a stool and going down the road at 55 mph....... gasket on gas tank plug was a rubber/fiber type we use in our business as well and looked good, so a little teflon tape at the bottom of the threads (doesn't make contact with the gas inside the tank) and that went back good too...

Thanks for all your help and suggestions.... let me know what you think about the two wires... and confirm what I found if you will....

PS.... mechanic friend and I looked at the air cleaner yesterday and understand the theory of the spring loaded closing device which closes according to temperature... but can anyone explain how it opens and closes and what that process is? mechanical? manual? the larger hose running from the manifold to this is pretty sad and will be replaced.. is that what controls where the air cleaner opening is open or closed? Thanks

Dennis

 

I reread my post... I am currently waiting for the combo switch to arrive should read... I am currently waiting for the ignition switch to arrive... apparently, I need more coffee....

 

The only red wire I see on any of the diagrams goes to the buzzer and the inhibiter for the auto trans. Since it is a male connector try applying 12v to it and see what turns on. Try ehat on the other male connectors. I could be shorted to ground which would explain the po's solution. Check th back of the fuse box foe melts. I have found that most elctrical problems are from corroded connecters. It causes high resistance which blows the fuses. Some people put bigger fuses but that makes it melt or even catch fire.
The combo switch wiring seems to be the same for all S30 cars. So now I'm pretty sure the red wire goes to the headlights and the blue/white wire goes to the wiper motor.
http://www.atlanticz.ca/zclub/techti...AR-WIRING1.pdf

 

Hey... Thanks for the information and the wiring diagram.... I have five different wiring diagrams and none of them are as good as yours. After I looked at a couple of my color diagrams and with a magnifying glass, I could only guess at what the red wire was simply because of the gauge of the wire. The only thing that made sense for that large of wire is/was the headlights...

So, what I am going to do is put this all back together but leave the two piece black plastic column shroud off until the car is completed, and the headlights etc. are back in the car. Then I can try everything on the combo switch and go from there....

Thanks again...

 

The heavier gauge red wire plugs into a red wire coming off of the combo switch. It carries the voltage for the headlights from the switch to the fusebox. In the wiring diagram on page 39 in the 1971 FSM supplement, it is shown as going to contact 20 on the combo switch.

There is also a smaller gauge red wire that goes to the buzzer when you leave your keys in the ignition. I don't think I've heard a working buzzer in a 240Z, yet.

 

Hey Steve... I can attest that my buzzer works..... I have the doors off the car now for painting, and the button is temporarily taped down and I have also installed a cut out on the positive terminal of the battery which I have on all my collector cars. The buzzer is annoying. When I did work, a long time ago, for Chevrolet, I can tell you that when these buzzers first appeared, most customers were very annoyed by them and would ask me to disable them. By law, we could not. But nobody said we could not tell the customer how to do it himself, and that is what we did.... I think I have a handle on this one, and have found several wires that are "free" and much of that is a result of aftermarket radios etc.....

I asked a friend for ideas about the console though and will ask anybody reading this for their two cents too.... The panel that is about four/five inches square that covers the fuse panel area in the console, was removed or cut out or whatever, necessitating a new fiberglass panel to be fitted here (see attached picture). I am going to install a power source here, but have room for several other trinkets to add to this space.... you know, things that are cute or switches etc.. has anybody had a need to add anything to their car that would fit in this area? A friend suggested a GPS but, the location is probably too low below the dash to access a satellite... ideas/ suggestions welcome.... otherwise, I will add a dual cigarette lighter power source and leave it at that. Thanks