I have a couple of questions about my gauges. On my ammeter the needle stays at a slight discharge whether the key is on or not. My temp runs between 190 and 195 which I think is fine. My gas gauge is now a 12 volt and stays just below 1/2 even with the key off or the battery unhooked. Oil pressure stays on 30 when the engine is running. This is a 1954 235 so I think this is good. Question is, why doesn't the gas gauge drop to E when off and why doesn't the ammeter move? Thanks, Gater
Gater, I've got more questions than answers on this, but maybe it will stimulate some "thought processes". Your sending unit is 6 volt. When you went to 12 volt, did you put a voltage reducer in the circuit for the sending unit? Do you have the gas gauge wired through the ignition switch? Is everything properly grounded? When you fill up the tank, does it read full or stay on "just below half"? As far as the ammeter, are you running an alternator or generator? Does it show a charge when you're running down the road?
Ken, Brand new 12 volt gas gauge and new sending unit. I will look at my paperwork and see about the voltage. Should be grounded good. The gauge is for a 1/2 ton cause I could not find one for a ton. Therefore the float does not reach the bottom of the tank. Therefore I would expect it to read low even with quite a bit of gas in it. I haven't filled it completely yet. When I put gas in it reads higher than just below half. Right now it is between half and 3/4 after I put in about 6 more gallons than I had. It is not wired through the ignition as far as I know but I will double check. I am running a generator but the ammeter does not move regardless of whether I am running down the road or it is off. Maybe it is fried? Gater
Gater, if it's not wired through the ignition switch, then it will be "hot" all of the time. You've got an "on frame" tank, right? Could it be that your sender does not go far even down to register anything less that half a tank? Ammeter should also read positive when cruising down the road unless the gauge is shot or the gen is not genning. Double check your "grounds"!
Gater, I would agree with Ken a lot of the newer fuel senders are poor quality. Try measuring the gas sender output at different levels of fuel. Should see a good swing as the tank get's lower. If you feel the ground is good maybe just pull the sender out of the tank then manually operate see how the guage react's. My quess sender is ok bad gauge. The Gen should be putting out better then that. Try putting a voltage guage on the output stem and rev the engine up then down. The guages can be fried very easy need to be very careful espically when switching to 12 volts. Output is very easy with a simple DVOM.
Remove the negative terminal from the battery and leave the key in the off position. Does the ammeter go to center? If it does there is current flowing somewhere in the system. Hook the negative terminal back to the battery. If you have fuses, remove them one at a time, checking the ammeter after removing each one. When (if) it moves to zero, that is the circuit that is active. If the ammeter stays in the same "slight discharge" position when you disconnected the negative battery terminal that position is the real zero position. Either live with it, open up the gauge and bend the needle a little (not advised) or replace the gauge.
My bad Does it change anything if I admit that I was thinking alternator when I wrote generator? I am running an alternator. YOu all have given me some things to do so I will have to do them and report. Thanks for all the ideas and sorry that my brain was not attached to my fingers when I typed generator. Gater
Gater, go to this site. It might be helpful in determining your gas gauge problem. www.fifthaveinternetgarage.com/tech_tips/tech_tips_gas_gauge.html Good luck with the gremlins!
By The Numbers : # 1: disconnect the battery ground cable , if the ammeter doesn't move , all is well , they're often assembled off center (remember how many times I mentioned poor QC in AD's ?) #2 :right as rain . #3 : gauge head is junk as you said it stays @ 1/2 with battery unhooked. # 4 : be glad , be very glad . # 5 a : see # 3 # 5 b : you may have one of the three wires on the back of the ammeter , on the wrong post as it should show a slight discharge when you step on the brake , and show some charge as soon as the engine starts and goes above idle . NOTE : the ammeter and charging circuit is entirely seperate from the ignition circuit ! the key should have NO EFFECT on the ammeter . FWIW , unless you have a frame mounted fuel tank , all AD's use the same gauge sender . I hope this helps . -Nate
I agree with Nate, I think your wire from your generator (alternator) is on the same amp guage post as the wire from the battery (starter post). Remove your sending unit from the gas tank and get two long jumper wires, run one from a good ground spot on the sending unit to a good ground on the truck and run the other from the sending unit terminal back to the "sender" post on the dash guage. Now you can move the float arm up and down, slowly, and watch the guage--no messing with gasoline involved. When the arm is down: empty, in the middle: 1/2, and all the way up: full. Most chevy guages work with 0-90 ohm senders so if you have an ohm meter you can hook one lead to the sending unit body and one to the terminal and test it. I'd rather use the first method because it's in the system it's going to be working with.
The other option could be that your primary route back to the battery is not thru the amp meter. I added an a/c, live in FL, and had to put a blower fan on the radiator. the main alternator output goes to the fan and then the battery. The amp meter is wired via the original harness, but of course the current takes the path of least resistance which is via the fan to the battery. The amp meter will go negative when the lights are turned on, but usually runs just a little positive.
Once I get my truck back together~ (next year??) this is the first thing I'm gonna' check! I'm just glad Gater asked it first! Thanks Gater!
When you guys who have your trucks done and are use to the gauges turn off your ignition, does your gas gauge needle drop to "E" or does it stay about where it is when the ignition is on? I checked two of my other cars tonight and on one of them it stayed put and on the other it dropped to "E' so that didn't help me figure it out. Take a look at yours when you have a minute and let me know, please. Gater
It's Not Important Because It depends on the typ of gauge , there's a few different ways of making them work so some will drop (mostly older) and some won't . -Nate
