water temp gauge

[MrMoonshineMan]

hey there, finally got my car running pretty smoothly, however, the water temp gauge doesn't work at all, and the oil pressure stays around 0 when idling. with the water temp gauge, i'd appreciate it if someone could take a pic of that area in front of the engine, as the guy who i bought it from had no respect for proper wiring at all, and i suspect he just stuck wires whereever he felt like. how would i go about checking it out? with the oil pressure, i've read over what other folks have said about it, what would i do after checking it by putting it to ground? can i buy the sending unit from anyold auto parts store? ok, thanks for all your help!

[Daniel]

The temp sensor is located in the thermo housing between the distributor and the head.When you ground the wire the temp gauge will go to maximum.The oil pres. sending unit is in the block below the 3 and 4 spark plugs.Ground it and it too should max out.If the reading is low during normal driving,odds are the sending unit is old/clogged.Replacement is easy,it just unscrews.Don't worry about oil pouring out the hole,it won't. Have fun!! Daniel

[MrMoonshineMan]

ok, so when i ground the temp sending unit wire (what i hope is the right wire, as there are a few dangling unmarked) the gauge goes crazy, it'll jump up past 250, hang around in the middle, go to less than 120, just cruise back and forth, everything, what do you folks think this suggests? btw, the wire i'm using does not spark when i ground it, there is another red/orange wire very near to it that does spark and blows out a fuse when its grounded, should i be using that one? it doesn't seem to have any effect on the guage.

[Daniel]

Sounds like you have the correct wire.If touching nothing the gauge is at rest.Ground and it moves.Does your oil gauge do the same thing?They will not spark. Daniel

[MrMoonshineMan]

yeah, my oil pressure gauge is working fine now guys, thanks. hmmm, so then its most likely my temp sending unit itself thats acting up? its almost brand new (its different from the original, but the paper it came with said it had just been redesigned but would work perfectly), is there a way i can test it? anybody have any ideas what that other dangling wire might be to? btw, the outside of the temp sending unit is grounded, so i don't think it is a problem with a good ground. thanks!

[Royce]

I have had problems with water temp sending units in the past and even a new one can be faulty. But before you go spending money lets get some more info, what are you working on 240-260-280? I have a few around and can take some digital pictures on Friday or may be able to respond with some ideas on the extra wires before then.

[MrMoonshineMan]

whoops, i thought i had posted this already. i have a 1973 240Z. everything besides the tranny is original, as far as i know.