sensors on t-stat housing.

[3ryce]

Ok I need help identifying what this is, I know this is what a temp sending unit it, check link.

Water Temperature Sending Unit, 240Z 260Z 280Z 280ZX 300ZX, Datsun Nissan

However I do not know what this would be called.

heres a picture.

the sensor, not the thermostat housing. This is off a 240z 1973. Thanks for the help guys. I was thinking fan switch but when at autozone it said the vehicle was not equipped with these.

[Zed Head]

That might be a temperature switch for a dual point distributor. It's kind of a mystery mechanism that Nissan kept up through the early EFI cars. It's not mentioned in the Emissions chapters, only the Electrical chapters. It advances the timing when the engine is cold. Maybe to keep the idle up or maybe it really is for emissions. Described in the Ignition section of the Electrical chapter.

Measure resistance on those wire ends and see if it's a switch or a sensor. If it's the switch, it only matters if you have a working dual point distributor.

[Captain_Zeros]

'73 Z owner here, I just went through this. It's a thermoswitch for the EGR system so that it won't activate when it's cold out. It's an undocumented change somewhere in '73 to a 260z style thermoswitch, earlier 240z had a thermoswitch inside the cabin for the same feature. See page EC-12 in the 1973 FSM and page EC-16 in the 1974 FSM for specific infos.

Edit: my car is build date 6/73 and was wired this way, my switch was non-functional and a previous owner removed the EGR system, so I just left it be.

Double edit: It's also nowhere near the temperature range to be useful for much of anything even if it does function, it should activate at a coolant temperature of around 100 degrees F.

Edited July 1, 2013 by Captain_Zeros

[3ryce]

Thanks for the info guys! ha that helps so much! ill prob just delete the egr then and throw a block plate on their. Is there a thread on here about deleting the egr? I will go do some search button options first I guess haha. Again thanks for the help. i love working on this old car and want to do something like that slammed 260z from holland guy did. strip it all down clean and repaint with anti-rust paint and ya. ok ha thanks.

[3ryce]

Ok, I was looking at the FSM in the emissions section on the first page where it has like numbers 1 - 15. well 14 says air pump. I dont have the whole system but there is that small one on or near the dizzy. sry my 240 is not where im able to run out to the driveway to give it a quick look. sucks. but im going to just remove anything attached to the smog crap and close off any left over openings and plug things up.

[3ryce]

ok so the 14 is pointing to the smog pump but im talking about the thing just above it. anyways ill use a photo editing thing and post a picture of what im talking about.

[3ryce]

Uploaded with ImageShack.us

ok that red triangle is pointing to what? I feel like it has something to do with smog and I want to remove it. It looks like i dont even have an egr so that one sensor seems kinda pointless. So I would assume its same to just plug it up. I mean its not like its gonna throw a code or anything .

[Zed Head]

You're on the slippery slope of guess-and-hope...

[Patcon]

looks like the vacuum advance for the dizzy. I wouldn't unplug that on a stock dizzy setup...

C

[zKars]

You have a replacement carb, intake and likely exhaust manifold from an earlier Z than your 73. None of the EGR and smog stuff that came with your car are there anymore. No smog, anything, anywhere. Cut the wires of the broken sensor put it back in the housing to plug the hole, and move on to more important things.

[Captain_Zeros]

What zKars said. The only emissions things that came on 240Zs were smog pumps, EGR, and flat top carburetors. Your car has all of these removed (as does mine!)

I've got a broken sensor plugging that hole on my car as well, "if it isn't leaking why monkey with it" is my take. I never could find a definitive on whether that plug is 1/4 NPT thread or whether it's 1/4 BSP, a lot of the fittings on these cars are british pipe thread which adds an extra hurdle to be aware of if you're going to start changing things.

[3ryce]

You're on the slippery slope of guess-and-hope...

Which is why I wish the car was at my place but for now it must stay where its at. if it was where I could just run out and look real quick then ya. I'm tryin to learn!

looks like the vacuum advance for the dizzy. I wouldn't unplug that on a stock dizzy setup...

C

Notes and will not mess with it.

You have a replacement carb, intake and likely exhaust manifold from an earlier Z than your 73. None of the EGR and smog stuff that came with your car are there anymore. No smog, anything, anywhere. Cut the wires of the broken sensor put it back in the housing to plug the hole, and move on to more important things.

Yes the owner before me that brought it to tenn. From cali. Had it all changed and supposedly to get rid of vapor lock but the fuel pump doesn't work unless you jump the wires, but that's for another thread. Thanks for the info.

What zKars said. The only emissions things that came on 240Zs were smog pumps, EGR, and flat top carburetors. Your car has all of these removed (as does mine!)

I've got a broken sensor plugging that hole on my car as well, "if it isn't leaking why monkey with it" is my take. I never could find a definitive on whether that plug is 1/4 NPT thread or whether it's 1/4 BSP, a lot of the fittings on these cars are british pipe thread which adds an extra hurdle to be aware of if you're going to start changing things.

I will try to find a plug for it and just plug it. I was trying to flush the old radiator fluid out and then bolting down the top half and stripped it and was taking the whole housing off and broke the wires and the senor and one bolt head. Ha. But I got that new radiator in there just fine.

Again thanks to all you guys yall are an awesome help!