put me out of my misery

[acl]

I know i have asked before and read lots of forums but still can not get the #@*! temp gauge to work. It will not move from far cold at all. I have grounded the wire to everything and it peg the gauge hot i have changed sending unit 3 times I have ask for and hopefully gotten gauge not light senders. I don't know squat about olhms and volts. Have a tester no smarts to use it. I do not have a ground cable from block to frame anymore but touching sending wire to block peg the meter so i think its got ground. will putting teflon tape on sending unit matter? i'm am lost and willing to trade house and kids for a right answer, just kidding i will keep the house. thanks to those who attempt to save my sanity, whatever is left. is the gauge good if it goes hot when grounded. maybe i am assumnig too much
gary

[slomotion]

If you have tape on the threads, take it off and try again. Your sending unit needs a good ground to work properly, and the tape may be insulating the sending unit.

[Longhorn Man]

slomotion is right.
If you remove the sending unit and look at the threads, they should be tapered. The tip is smaller, and it gets larger as you thread it in. This is designed to not need thread tape, and as he said, the tape (esp if you wrapped it in 3 or 4 layers) can hinder the ground it needs to work correctly.
you are right in the assumption that your guage and wire are in proper working condition since it pegs upon grounding.

[acl]

more info- had p.m. jimKshortstep4x4 (thanks Jim) and he thinks it might have to do with late 70's block with 68 gauge set -up. Does this matter and what do I do. The senders are different size and i don"t think a 68 (no 350 in 68??) will fit in the block any back-up to jims help. thanks to all Gary

[WorkinLonghorn]

Just take off the tape!

[DREAMS OF A 67]

do you have a good themostat ?

[elektrik]

Originally Posted by acl

...Have a tester no smarts to use it

Ok, since you mentioned you have no smarts to use your meter, here's a meter reading primer - I'll be using mine to explain. Hopefully it will be similar enough for you to use your meter.



Ok, on my meter the left side is "Ohms" or resistance. You can use this side to test grounds or resistance (In the simplest terms, a resistor is what is used to create current when a Voltage runs across it) levels. There are varying dial settings on mine from 2 MEGAOhms resistance all the way down to 200 Ohms. If you're measuring resistance and if it's a digital one like this one, you should start with the highest setting and switch until settings until you get a reading. For example, if I have something that reads 150 Ohms, starting at the Highest setting-if I don't get a reading, I'd go to the next setting on the dial, etc. until I see a number on the display (this should still work with the old analog style meters, the difference being as you dialed down the levels, you'd see the needle jump higher).

There's one more setting which you may find more useful than even the resistance function. On the last setting, you can see a little icon that looks like a speaker. This setting is called "continuity". When you test two ends of a wire, you'll hear a beep. This lets you know that the wire is unbroken from one end to another. This setting is also great for, you guessed it-testing whether the wire is grounded properly.



Now, when you're measuring resistance, you may need to switch the terminals to the right holes. In my meter, when I want to measure resistance, I have to put the black terminal in the middle or "COM" and the red on to the left. When I want to measure voltage, I have to move the red terminal to the right where the "V" is.



This is the back of my temp gauge. The top and bottom terminals are ground, and the right one (if you are facing the back of the gauge, like the picture) is the "ground". all you have to do, since the gauge has two terminals is setup your meter like mine on the continuity setting, put one lead on either the top or bottom terminal and then touch the right terminal with the other lead. If it doesn't beep, try doing the same with the left terminal. If neither beeps, you know your gauge somewhere isn't grounded to the chassis. If it does beep on one side, you'll know at least the ground is working.


Hope this helps!

[acl]

Originally Posted by DREAMS OF A 67

do you have a good themostat ?

yes good thermostat thanks

[LONGHAIR]

Just take off the tape!

Yeah^^^^ the tape is insulating the sender from ground. You can test this as simply as touching a wire from the sender body to ground, with the engine warm of course and key on too.

[Sport/Truck]

I wouldn't have guessed the tape.....it makes sense. Will Teflon paste work? (That's what I would have used.)
s/t

[Sport/Truck]

Originally Posted by acl

I know i have asked before and read lots of forums but still can not get the #@*! temp gauge to work. It will not move from far cold at all. I have grounded the wire to everything and it peg the gauge hot i have changed sending unit 3 times I have ask for and hopefully gotten gauge not light senders. I don't know squat about olhms and volts. Have a tester no smarts to use it. I do not have a ground cable from block to frame anymore but touching sending wire to block peg the meter so i think its got ground. will putting teflon tape on sending unit matter? i'm am lost and willing to trade house and kids for a right answer, just kidding i will keep the house. thanks to those who attempt to save my sanity, whatever is left. is the gauge good if it goes hot when grounded. maybe i am assumnig too much
gary

Maybe the lack of ground to the cab would cause it to not work? There are two braided ground cables from the block to the firewall. The motor is setting on rubber blocks (no ground) the cab is setting on rubber pads (no ground). There will be a small trace of continuity through the metal fuel lines etc. But not enough to operate things. Does your radio work? Is it grounded to the cab?
s/t

[LONGHAIR]

Sport/Truck,
While I agree with you that it really should have a ground cable driectly from the frame to the engine....you stopped "highlighting" a few words too quickly.

touching sending wire to block peg the meter so i think its got ground.

If the sender wire from the guage pegs the meter when touched to the engine, it has ground, at least enough for the guage to work. Since he didn't say that the truck doesn't start or run, it must be getting good enough ground somehow.

I wouldn't have guessed the tape.....it makes sense. Will Teflon paste work? (That's what I would have used.)

It might, but you are still taking a chance. Tapered threads, especially with soft brass fittings, should seal just by tightening.

[Sport/Truck]

^
^^

I think it starts because the neg goes directly to the block and not the frame.
Grounds can be funny because of resistance issues (rust, loose connections etc) causing poor grounds.
I did read the rest of that statement but still thought it was worth noting.
It would be a easy test to just run a ground from the block to the firewall.
s/t

[acl]

Originally Posted by LONGHAIR

Sport/Truck,
While I agree with you that it really should have a ground cable driectly from the frame to the engine....you stopped "highlighting" a few words too quickly.
If the sender wire from the guage pegs the meter when touched to the engine, it has ground, at least enough for the guage to work. Since he didn't say that the truck doesn't start or run, it must be getting good enough ground somehow.


It might, but you are still taking a chance. Tapered threads, especially with soft brass fittings, should seal just by tightening.

should i put the ground from block to cab or block to frame or both????

[LONGHAIR]

Both never hurts, your ground can't be "too good".

[byrd]

most gauges that read low at operating temps have a weak resistor on the back, the wire mesh or porcelian piece between the two center studs. You should change that out and it will most likely fix your issue. FWIW most of the temp gauges only move to about an 1/8" past the begining off the solid line across the face of the gauge, when at operating temps. If you have an 165 deg T-stat that would also make it read low.

[acl]

going out to put all this good advice to good use i hope. any comment on the different years for sender (Late 70's) and gauge 1968?? should work???
thanks to all and will let you know the outcome maybe it can help someone else.
Gary

[byrd]

Originally Posted by acl

more info- had p.m. jimKshortstep4x4 (thanks Jim) and he thinks it might have to do with late 70's block with 68 gauge set -up. Does this matter and what do I do. The senders are different size and i don"t think a 68 (no 350 in 68??) will fit in the block any back-up to jims help. thanks to all Gary

Sending units and gauges were the same 1967-72, 69-72 the 350 was availible then, you can still get the correct sending unit from GM, or one of the board venders.

[70c10]

I'm glad I saw this thread. I didn't realize teflon could affect the temp gauge!. I think I used it but mine reads normal on my aftermarket gauge. Good luck acl