fuel sending unit?

[brotherdavid]

I installed a new fuel sending unit in my 3a with a 6 volt system. (part#640694). my problem is if I actuate the lever just a small amount it goes to full on the fuel gage. then if I release it all the way down it goes to about 7/8 full on gage then if I move lever up again it goes to full. So the fuel gage is only going from 7/8 - full in the full range of the travel. I have the unit grounded well. Also I believe the fuel gage is good because when I ground out the sending unit wire it goes to full on the fuel gage and when I remove ground off the sending unit wire it goes back to empty.

[rocketeer]

Sounds like maybe you have a defective sending unit. Can you exchange it?

Larry

[Carls_jeep]

It could also be the wrong sending unit. Contact the supplier.

[brotherdavid]

got new fuel sending unit again. it now works. first one was defective.
                                  THANKS

[calvinhunt]

brotherdavid,
 ï¿½Where did you get you fuel gauge and sending unit? �I have a six volt system and have had nothing but trouble. �I'm ready to start over. �Your response will be appreciated.

[rocketeer]

What kind of trouble are you having Calvin? The first thing I recommend to anyone feuding with their gas gauge is to run a separate ground wire from one of the sending unit retaining screws to the tub, making sure it has good bare metal contact at each end. Secondly, make sure the dash gauge has good contact with the dash as it too needs a good ground to function properly and thirdly, these bloody things never are completely right. The only time you will get a true reading is if the jeep is sitting on a perfectly level spot and not moving. Otherwise that needle will move all over the place because there are no internal baffles in the tank and the sloshing gas bumps that float up and down virtually all the time the jeep is in motion. �:)

Larry

[jamesr]

Although my tank has a baffel, my gauage still slops around. I converted to 12 v. replaced both sending unit and guage, and ran a seperate grnd for the sending unit.  I had to bend the arm to read accurate from 1/4 down, while on the bench, and prior to installation of the tank. Above 1/2 it is "full" (on the bench). After installing and driving it, at 3/4 it begins to bounce, and at 1/4 I stop for fuel. Even though I know there is 2.5 gallons in it. I also carry a "whiskey stick" in case I want accuracy to the inch.  Jim

[brotherdavid]

calvin, my fuel gauge is the original from 1953, as for the sending unit it is part# 640694 that i ordered from walcks. Upon more playing around with it it is kind of eratic on the needle. I dont know for sure how good it will be until I drive it around more, and if i run out of gas before it reaches empty on the gauge, O BOY, I think I to will use a whiskey stick and monitor the fuel level until I can really trust it. I'll keep you updated on this as I just finished a total restoration of the jeep and haven't got much drive time yet. she'll be ready to roll for sure on the 4th of july for the local parade.

[calvinhunt]

Thanks for each of your responses to my request.  I should have clarified that I have a new 6v 3-wire gauge and sending unit from Walck's.  You may remember a couple years ago we had a thread going about fuel gauge problems.  Mine and others acted like an ammeter.  The higher the RPM the fuller the fuel gauge read. I soldered a small resister-looking 6v regulator into the circuit.  It worked for a while and then died.  I thought that if it would just work sitting still before I started the engine, at least I would have a good reference.  Now it just reads anywhere and never ever accurate.

Larry, I know you're right about the positive grounding and the sloshing of the fuel when moving.

jamesr, How did you get a tank with a baffle? Your idea of a "whiskey stick" has already been adopted.

brotherdavid, Occasionally I've seen a working gauge on eBay.  Maybe I'll keep watching and then get a sending unit from Walck's.  Keep us posted.

Maybe gas gauges for these old Jeeps should be called "guess" gauges.  I'd just like to get better performance than I presently have.  Your advise and help is appreciated.

[jamesr]

Calvin, my original tank had a baffel, and the original guage still bounced around (untill it stopped working altogether).  I bought a reproduction tank from Walks, and it too had a baffle, but it had 2 or 3, half inch holes punched in the top and bottom of the baffel, where the original tank had slits where the baffel welded to the bottom of the tank. I converted to 12V so had to buy matching guage and sending unit. You can't stop a slosh, but you can slow it down. Jim

[calvinhunt]

So my question is, "Has anyone purchased a 6 volt system--sending unit and gauge--that they are pleased with?" �I don't care if it just works correctly when stopped. �If so, I would be willing to try to get one from the same source and start over again. �Honestly, that is the only disappointment with my entire restoration. �Where I have literally worked out all the other bugs, this one remains aloof. Thanks.

This was really "brotherdaivid's" topic.  I think he got the help he needed.  Sorry to have taken it over.  

[Chasm]

The gas gauge issue will be ever present as more folks restore these old Jeeps. We are all spoiled by our modern vehicles with their on board computers calculating how far you can go 'til empty!

I have all but given up trying to get my gas gauge and sending unit to work. After grounding everything, testing, replacing, and so on, my wooden dipstick is still the best way to go. Yes, I ran out of gas one time and even had folks stop to take a photo! �>

I'm thinking about mounting my jerry can as a back-up in the future!

[aboyandhisdog]

So my question is, "Has anyone purchased a 6 volt system--sending unit and gauge--that they are pleased with?" ��

Like everyone else I tried about every combination of sender / gauge out there.  I did learn that there is no such thing as 6 volt, 12 volt, 24 volt fuel gauges and senders.  Apparently system voltage has nothing to do with it.  The important thing to determine is that both sender and gauge are compatible in regards to "Ohms".  You can buy senders and gauges sold together that are compatible.  The biggest mystery to me is that when I run the sender out of the tank, the gauge will work perfectly but as soon as I secure it in the tank (yes, with an excellent ground) it won't work as well.  I currently have a Sunpro gauge and sender.  Works perfectly out of tank but as soon as I install it, a full tank only reads 3/4 on the gauge.  I can live with this, but can't for the life of me figure out why it won't read full.  And, yes, the float arm is adjusted correctly to be at the top of its travel inside the tank.  

[jamesr]

A back up Jerry can is the most accurate fuel guage there is.  If you remember to fill it.  Been there done that too! At that time, I could not blame old age either. Jim

[rocketeer]

�I currently have a Sunpro gauge and sender. �Works perfectly out of tank but as soon as I install it, a full tank only reads 3/4 on the gauge. �I can live with this, but can't for the life of me figure out why it won't read full. �And, yes, the float arm is adjusted correctly to be at the top of its travel inside the tank. �

That's because the float is reaching the top of it's travel before the arm reaches the stop. You can correct that by bending the arm DOWN slightly. It may take a little experimenting until you get it right.

However, the important reading is not Full but Empty. The way to set up a sending unit is to do it on an empty tank and make sure that when you install it and connect it up it reads Empty without the float hitting the bottom of the tank. It should hang about 1/2" above the bottom. The length of the arm is critical. It MUST be the correct length in order for the gauge to read accurately thru the entire arc.

Larry