LOUD ringing noise from inside . .

[New-to-240z]

Well, i figured out it was the seatbelt light not showing up. It went away the second i pulled on the seat belt!! YAY!

I also followed the wires for the switch. They ran back to the fuel pump . . . any ideas? I'm, going down to the shop that did this and asking them what the hell its for

[sleepyzzz]

i am new at this so i am sure that this is just a guess,but i would think it is a cut off switch to stop the fuel pump incase of a wreck.

[Nissanman]

Unless the fuel pump is running on less than 12V and the switch provides the full 12V:eek:

[Mr Camouflage]

Well, the z originally came with a mechanical fuel pump. Not sure when they added the electric fuel pump in the US.

My guess is that a PO (Previous Owner) added an electric fuel pump, and that is the switch to turn it on/off.

[Ramses]

On '73's in the US, the dealer installed the electrical fuel pump to help with the original flat top carbs fuel starving. Normally it was powered through the connection from the engine bay harness and the voltage regulator. When everyone replaced the flat top carbs with the SU's then the electrical fuel pump became unnecessary. I am not sure why Datsun started going with the flat top carbs, but I guess that it had something to do with the emission crap that everyone also removed.

[New-to-240z]

i'm guessing a good way to tell is if i push the switch down and try to start the car, and it doesn't then its a cutoff switch. If it starts then I'm, guessing that its what nissanman was thinking. It supply's extgra voltage to the fuel pump causing more fuel to be dropped in. I'm going to try it out today and see what happens.

I'm noticing that the car is running XTREMLY rich, and this might be the reason. Will report back.

Thanx for all the help guys!!! BIG THANX!!

[EScanlon]

The wiring for the fuel pump in 70-73 Z's AFAIK based on wiring schematics was a Green wire that was powered off the same BW wire that connected to the Ballast Resistor and the Tach. In the 73's, specifically, with the addition of the seat belt warning system, that warning system was ALSO powered off the same BW wire.

That you found continuity between the wires at the seat belt switch and the fuel pump is correct as that IS how the car is wired.

The only mention of a "cut-off switch" was by SleepyZ, in reference to the seat belt / fuel pump commonality of wiring, but this is simply a guess on his part.

If at the fuse box area you find the connector for the in-line fuse holder that then powers the wiring for the fuel pump, you could then install an electric fuel pump to replace / suplement the mechanical one. However, do note that excessive fuel pressure in the supply line to the carburators has proved to be problematic, as the fuel tends to seep it's way past the float bowl.

So, hopefully this clears that up.

However, one question does arise;

The Z's had a provision for BOTH seats to trigger the Seat Belt Alarm if occupied, unless you have a very heavy cell phone that you park in the passenger seat.....How is it that you've (presumably) been driving the car WITHOUT putting on your seat belt?

E

[New-to-240z]

well, i just got the car, and haven't drivin it except in my neighborhood and never put the seat belt on. After putting on the seat belt the sound went away. So that has been figured out.

As for the switch, i went to the shop today and he told me exactly what NissanMan had said, The switch when turn on sends more power to the fuel pump for more gas to be pushed. But, thinking about this, the only time I would EVER need to do this would be when i have the gas at full throttle and am nearing 4-5K rpms . . . . right?

Also, i just did a oil change and found that the oil hadn't been changed for over a year and that the previous owner only put in 4.3 Qts of oil. So, i switched it out and dropped in 5qts and a new filter. (mobile 1 & 10W-40) The car is running much smoother now, and i'll be checking the trans dip stick to see if i need to add anymore to that.

But i have come upon other things that i have a question about.

1) In tons of pics i see these Fuesable link setups, like in http://www.classiczcars.com/forums/showthread.php?t=25506 but i don't have this anywhere in my car. I only have the one behind the dash (picture in this thread. one with the switch) I was wondering if the 73 came with this or not.

2) This is the dumbest question, but where the hell does the over-the-shoulder buckel well . . . buckel into? I clip the lap belt straight across, but i can't for the life of me find a spot to hook in the chest belt?? Any help?

[ChrisA]

where the hell does the over-the-shoulder buckel well . . . buckel into? I clip the lap belt straight across, but i can't for the life of me find a spot to hook in the chest belt?? Any help?

The shoulder belt should attach to the lap belt buckle. Its a two piece affair. You have to align the two together first then buckle the lap belt into the receptacle.

No stupid questions here except the ones that don't get asked!

Have fun with the Z!

Chris A.

[Ramses]

Look under the connector strap that goes through the buckle...you will find a small t looking opening. That is where it slides into.

I dont believe that there are any fusable links in the engine bay.

[EScanlon]

The shoulder belt should attach to the lap belt buckle. Its a two piece affair. You have to align the two together first then buckle the lap belt into the receptacle.

No stupid questions here except the ones that don't get asked!

Have fun with the Z!

Chris A.

This is one of those "quirky" things about our cars.

Look at the SHANK of the rivet on the over-the-shoulder clasp and you'll see that it has the sides flattened...not from excessive wear but by design. That "thinned" out portion of the shank will, when aligned to the slots in the back portion of the lap belt's clasp, will slide THROUGH those slots and then be CAPTURED by the round hole that the slot connects to.

Typically once you've "threaded" the pivot, most people just leave them attached and then hang the belt and shoulder straps off the hook on the rear quarter panel's interior. Just aft of the door opening.

This hook can accept the lap belt's clasp via the square hole in it in case your belt's shoulder strap has lost the round loop of material that should be put there.

Hope this answered your question.....

Sorry for laughing, but once you've read my explanation, and then tried it, you'll see why it's quirky to explain.

FWIW

E

[ChrisA]

Sorry for laughing, but once you've read my explanation, and then tried it, you'll see why it's quirky to explain.

FWIW

E

You did good explaining quirky! Nice job in Nissan Sport with the tech help too.

Chris A .