New Auto Meter Gauge/Sending issues

-
smartken22

smartken22

U.S. Navy Senior Chief
Joined
Feb 20, 2011
Messages
887
Reaction score
75
Location
Lemoore, California
So now that I finally have fuel in the car and have her running I need to figure out why this fuel gauge is not working. Everything is brand new. The gauge is an Auto Meter 5715 rated from 73-12ohms and the sending unit is a new factory 3/8 unit from Vans Auto rated at the same ohms. I have 5 gallons of fuel in the tank now and it reads zero on the gauge. I should at least be reading 1/4 or less. I pulled out the fuel filler tube and stuck a coat hangar in there to lift the sender and once I pulled it all the way up, it finally read full. There is no in between. It either reads totally full or empty. Ideas? I have exhuasted my options with the search so now I am looking for help. All grounds are good and everything is temporarily run straight to the battery for troubleshooting purposes. My next option is buying a full sweep programmable gauge if all else fails.
 
are you bypassing the dash board voltage regulator ?
 
It's either the gauge, wiring or the sender, and you should be able to easily run this down

Make certain the gauge actually has battery voltage to the gauge.

Hook your multimeter to the sender alone, and slowly move the sender through the entire sender movement. It should "smoothly" move from the range of resistance, and "about" halfway should be about 25 ohms. These are not what is called linear and might be a little hard to estimate.

If I had to guess, I would guess the sender is losing connection in the middle.
 
OK thanks. When I get home tonight I will take the sender out and move it around to see what we are actually looking at. It is a new sender and I talked with Vans Auto and they said if the sender reads bad they will send me a new one. They said they get a bad one here and there and I may have gotten a bad one. I will break out the meter tonight and posts my results. Thanks for the info!
 
I have an auto meter gauge in my dart and a sending unit from Vans as well... my issue is a strange one as well.. If I fill the Dart up, it reads full... however, it will work its way down to reading 1/4 tank in no time... Found out the hard way that if it is reading 1/4 i still have a little better than half a tank of gas... trouble is once it gets down to a 1/4 it slows down and doesnt move for a good while.. So while I have taught myself that 1/4 means half or better... I have no earthly idea whats going on from there.. havent pushed the issue yet, but I get the impression I would run out of gas with the gauge still reading 1/4 lol
 
You guys might want to sit down with some test resistors and justify how the Autometer gauge compares with the original "specs" The Mopar gauges were supposed to test as this:

L = 73.7 Ohms (empty)
M = 23.0 Ohms (1/2)
H = 10.2 Ohms (full)

Maybe the Autometer gauge is nowhere as "matched" to the original scale as it might be
 
Here is a link that may help explain things.
http://www.autometer.com/tech_faq_answer.aspx?sid=1&qid=56

The main problem is that the ORIGINAL FACTORY tank sending unit is NON-Linear in design,

Most if not all of the replacement ending units on the market although they look the same are LINEAR in design.

This is also why folks still have "fuel gauge" problems after replacing the tank sending unit with a "new" aftermarket replacement.

I will try to post photos of the internals of both types later.

Herb
 
[quote="Dart67";1970413715]Here is a link that may help explain things.
http://www.autometer.com/tech_faq_answer.aspx?sid=1&qid=56

The main problem I that the ORIGINAL FACTORY tank sending unit is NON-Linear in design,

Most if not all of the replacement ending units on the market although they look the same are LINEAR in design.

I will try to post photos of the internals of both types later.

Herb[/quote]

This makes sense... And if this is the case my fuel gauge will again be accurate as it gets to the empty point... So totally full and totally empty would be spot on. Everything in between would be a mystery lol
 
Either that or see if you can adapt a Ferd sender resistor into your Mopar sender
 
OK guys here are the results from tonight's meter party. I took the sender out and at empty it reads dead on 73 ohms. When I move the float all the way up I read 8 ohms. I slowly swept it from top to bottom and the meter was sweeping higher and lower with the movement so the sender is working properly. Our only thought was that there was not enough fuel in her. So I went and bought five more gallons and now it reads 1/4 tank. I put another five in it and it is almost reading full now. It is reading in between half and full and there is roughly 14 gallons in the tank so it seems as though everything is working as advertised. It just drops a little faster once on the empty side. Additionally this was the first time that I put fuel in the new tank so I noticed when the sender was removed that the pickup tube/float do not sit all the way on the bottom of the tank. I would say that there is at least 2 gallons of gas in the tank before it even hits the float. The fuel pickup tube is lower than the float which would make sense on the readings. Basically when the first 5 gallons went in, the sender only detected three or less gallons due to the free space. I dont think she is quite full yet so I will keep adding fuel until it gets to the top and I think it should be good. Thanks for all the help guys.
 
Damn man you read my mind! We were just discussing this at work today when reading up on the tech info on Auto Meters website! Very good gouge as I did not understand the difference between the two. I had to get my avionics guys to help explain this to me!

[quote="Dart67";1970413826]Here is a link to a post that I just made about the Types of fuel sending unit resistor boards.

http://www.forabodiesonly.com/mopar/showthread.php?t=274770


Herb[/quote]
 
You must log in or register to reply here.
-

Back
Top