[z10kl]

I have read many posts and have learned alot but any hints on this? My temp is peged to cold. I took the wire off sender and touched it to ground and I can here it peg to hot. I immediatly remove from ground it slams back to cold. It dosen't move gradually it's like Bam Bam.
Reading Mark Cs post he said disconnect wire in trunk and it goes to full. When I ground the wire it only goes to a little over half full and stops. When I plug it back in it is on empty. Every think is new except the gauges.
I went and bought a digital multimeter and which setting do I use to read ohms?

[alanrw]

The scale that has the Omega on it.

BTW, which gauge are you trouble shooting, the temp gauge or the fuel gauge? If it is the temp gauge, you really shouldn't be in the trunk.

alan

[z10kl]

Both
There are 6 different settings from 200m to 200

[alanrw]

You can use the 200 scale to check the sender reading at the gauge. The range on the fuel sender is 0-90 ohms.

Check to make sure your grounds at the gauges are good. Seems to be a lot of troube when the gauge grounds are iffy. To check the grounds, set the meter to 200. Put one end on a good chassis ground and another on the gauge ground. The meter should read 0.00. If it reads numbers, you have ground issues.

alan

[z10kl]

On the fuel gauge, I unhooked the plug in trunk and checked the wire to tank with a digital MM and got 00.2. I was expecting to get around 10 to 20 based on how much I think is in the tank. I had already checked the ground wire in front of tank and appeared good.?????

I checked the temp sending unit in the head and got no reading with one lead on stud and the other grounded. Do I have to take it out to check?

[alanrw]

On the coolant sensor in the head, I bet the sensor is bad but for giggles, warm up the engine and then test the sensor again. If the reading is the same, I would replace the sensor in the head.

You are on the right track.

Edit: I just pulled out a new consol gauge coolant sensor I have. Cold, it measures 750 ohms. I then put it in a cup full of hot water and it then measured 247 ohms.

Recheck your sensor after you bump the ohm scale up to 2000 ohms on your meter.

Also, look up how to use a DVM on google. I am pretty sure when you are testing circuits like this you don't want voltage running thru them as it will skew the readings. I always just disconnect the battery when doing these tests

alan

[z10kl]

OK, I verified what I was testing on the fuel sending unit by doing the same thing on another car. When I checked it I got 68 ohms. I checked the gauge and it had 3/4 tank. I like it when something makes since. So I rechecked the unit on the subject car with a wire ran from neg bat terminal to the ground wire from unit to be positive I had good ground and got the same 00.2. So I know I have a issue with the sending unit which is new. I am a test light kind a guy. But I ain't to old to learn.

[alanrw]

I have always operated under the theory that whatever I am trying to learn, somewhere, someone dumber than me has mastered it.

Either the fuel sender is bad or the wire to the fuel sender is bad? Run the tank empty, drop it, check it all out. If you do replace the sender, bench test it before you install it.

alan

[z10kl]

In addition to the sender, what should happen when I ground the wire in the trunk? The gauge only goes down to half or a liitle over half. When every thing is hooked up it is on empty. When unhooked in trunk it goes to full. Should it not go all the way to empty when grounded?
Now on the temp I took the sending unit out of the block and If I am reading it right it has at room temp 870 olms. When it was in the block it read about 1140. I guess the coolant is pretty cold in there.

[alanrw]

Check out this sticky:

http://www.camaros.net/forums/showthread.php?t=71062

Lots of good info. Check out Fuel Gauge Issues

alan

[z10kl]

Can someone verify that grounding the wire in the trunk should send the gauge to empty?

[z10kl]

Yes it will unless some idiot spends a day and a half grounding the wire with a test light. It dawned on me riding down the road. Grounded with a wire and it goes all the way.

[yellow69RS]

Originally Posted by z10kl

Yes it will unless some idiot spends a day and a half grounding the wire with a test light. It dawned on me riding down the road. Grounded with a wire and it goes all the way.

In my experience grounding it with a test light typically puts it at half tank. Grounded direct should put it below empty.

Jeff

[Mark C]

Originally Posted by z10kl

In addition to the sender, what should happen when I ground the wire in the trunk? The gauge only goes down to half or a liitle over half. When every thing is hooked up it is on empty. When unhooked in trunk it goes to full. Should it not go all the way to empty when grounded?
Now on the temp I took the sending unit out of the block and If I am reading it right it has at room temp 870 olms. When it was in the block it read about 1140. I guess the coolant is pretty cold in there.

You don't have teflon tape, or plumbers dope on the senders threads do you?

[z10kl]

No teflon tape. I took it out and put sender in water from microwave with my digital meat thermometor and at 205 it was just past half way on the gauge. At 170 it just past 1/4 mark of gauge.