fuel sender pi$$ing me off

[Jim]

Okay, just got done replacing the 5/16 fuel lines and sending unit on my Challenger with 3/8. Keyed it up to make sure the gauge worked and it barely budges off E. 

I dry checked the unit out of the tank before install and it worked, although not quite to "F". I also grounded the lead and the gauge shot to full.

This leads me to believe my float is sinking.

BUT, I got similar results off the previous sender. Never could get it to read past 1/4 tank.

Wondering if the voltage from the gauge is low. Haven't checked it yet. Should it read 5V, correct? Maybe time for a new instrument panel voltage regulator?

[Jim]

Just checked the voltage. Not getting a steady reading. Ranging from 0-12. Definitely the old-type regulator.

Priced a new one. $40. Ouch.

Am I on the right track?

[Strawdawg]

you might consider one of the solid state units...might not be a lot less costly unless you build your own..but, should be a lot more effective

[Cooter]

I learned one thing when dealing with aftermarket Sending units.....NONE of 'em work properly as OEM...
All have reading problems..About the best you can hope for is a "Rough guess" as to how much fuel is in the tank.....This holds true for the '57-'61 stuff and the '62-'74 stuff.....I bought a NEW 3/8 one for over $100.00 back in 2002 and it has never read over half a tank...Reads "Fair" from 1/2 tank down, but fill it up and you still have around 3/4 tank.....

[Jim]

I've built my own before, but they are a bit of a PITA to install with the IP in the dash.

Pretty sure the new ones out there are solid state. The BWD R307 seems to be what everybody is selling.
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Instrument-Cluster-Voltage-Regulator-BWD_3040151-P_947_R|GRPBODYAMS_559289299___

[ShelbyDogg]

If your regulator was screwed up, your Temp and oil pressure guages would flake out too.  Stick with troubleshooting the sending unit.   I usually file off a little of the coating on the exit tube and solder a clean wire to it. I then ground the other end with a screw right on the shock cross member.

Pull your sender out again and work the float up and down to check the gauge again and to make sure that you float didn't leak.  All 3 of my new 3/8 sending units are close to accurate.

[Jim]

Pulled the sender and double checked it. It ohms out ~ 20-80, same as the 5/16 OEM Mopar one I removed.

I reinstalled and ran a redundant ground to the body.

Still with over 5 gallons in the tank, it barely reads above E. Need to top off the tank and see if it goes to full.

No telling if the other gauges read accurately. Really haven't paid much attention to them other than to make sure they are in the normal range.

If it doesn't run to F after topping off, I'm going to make a trip to Radio Shack for a 7805 VR, heat sink and 100 uF capacitor. For about five bucks, I'll make an new VR.

[ShelbyDogg]

When you had it out, you should have swung the float to the top to see if the gauge read full.  If so, you might just have to bend things a little so that your gauge matches the gallons. Bend the float arm up or down and also bend or rotate the pick-up so that the filter tip is rubbing the bottom. I have mine so that when I see "E" I still have about 2 gallons left.

[Jim]

At the top of the range, it goes to 3/4.

[ShelbyDogg]

At the top of the range, it goes to 3/4.

  At the top of the range, that should be like you almost grounding the wire straight to ground. I would open it up and see what is causing resistance when all the way up. Maybe the wiper is bent on the resistance wire and not sliding all the way to the bottom. Very easy to check then put back together.

I read your 1st post saying that your gauge shot all the way up when you grounded that wire, so stick with this end of the car for now.

[Super Blue 72]

 

[Chryco Psycho]

Dave at Roseville has the best senders I have found

[72rtchallenger]

Dave at Roseville has the best senders I have found

i put one in about 3 yrs ago and it reads perfect,,with 5 gallons of gas with a 15 gallon tank it should read just above a quarter of a tank,,sometimes you have to tweak a float and use a good ground,,and it should have a pluse when checking for voltage,,as you said you check the omhs it is good,,so your float is off or weak ground,,but always use a good sending unit,as the cheaper ones are just that,,you say when grounded the gauge goes all the way up,so that just leaves the float an unit

[brads70]

     Just watching and learning....I want to replace my sender someday...

[wally426ci]

I have an NOS one in mine that sucks too.