Please help fuel guage not showing proper fuel levels

[raltz]

please help, if anyone had this problem before can you please help,

my fuel guage doesn't show the proper fuel level, well basically it doesn't work it stay at "E"

how can i tell if the guage needs replacing or if its something else,

please help and please be as descriptive as possible, sorry but i am new to the whole datsun world, these cars are different for me

Thank you

[d240zx2]

http://www.classiczcars.com/forums/showthread.php?t=38577&highlight=fuel+guage

You may find more info using "search."

[Nazgul280]

That's a good post to read.

Start with the basics. Since you didn't tell us what Z you have, I'm going to assume it's an S30 (1st gen). Has the car been sitting for a long time? If it has, corrosion of the connections or the sender would be the first thing I would check.

Before you get to pulling the sender out of the tank, your problem could be where the wires are attached to the sender. Mine were broken, so I used solder to make the contact good between the sender and the wiring harness, then covered it up with silicon to protect it from the harsh environment where it is.

Anyway, read that post that was supplied to you and see what you can find. If your still stuck, someone here will try to help, but be as descriptive as you can with what you have done to find the problem. (and include the model of the car too)

[Kathy & Rick]

Back in the day at Bob Sharp, I remember we would occasion-ally (but rarely) experience a perforated float. This would

cause the float to sink partially or totally, rendering an

inaccurate (always low, never high) reading.

FWIW,..............~Rick~

Edited August 31, 2010 by Kathy & Rick

[raltz]

Thank you guys, i do have a 1973 datsun 240z,

again sorry guys im new to this so im not sure what the part is called but there is a part that is attached to the tank that has two wires coming out of it that run to another part that looks to be attached to the chasis (fuel pump or is that the sender) but regardless there is a blue wire connected to to that part attached to the chasis which the blue wire runs into the car, and the part coming out of the tank with the two wires one is connected to the part on the chasis, another the other is just dangling there, black in color, and the part connected to the chasis has another wire that seems to run on top of the tank...

sorry if i sound confusing, i hope it makes sense, i thinking that wire coming from the part connected to the tank should be connected somewhere, but where? there are no other wires loose for it to connect to.

[EScanlon]

You really do need to do some reading, as this is beginning to sound like a troll prank or like someone who really doesn't know much about cars. Not flaming you, just calling it as I see it.

The wires you mention coming out of the "tank thing" are the wires are doubtful as that part is the Fuel Level Sensor. They are typically a pair of "t" studs instead of wires coming out of the tank. There should be two wires connected to it for the Fuel Gauge to operate properly.

FWIW

E

[biddljj]

I have the opposing issue... Fuel gauge always full.. Disconnect the fuel sending unit

and the fuel gauge goes to empty.. This has me thinking I need a new sending unit...

I ordered a sending unit while the memory of almost running out of gas while test driving at night was fresh in my mind.... I was driving at night to experience all the lights working...

Jay

Not just a Z - ZDisease

[raltz]

trust me this isn't a "troll prank" (whatever that is) i do know somewhat some stuff about cars, sorry im no pro, this is why i coming to you guys for help,

as i stated in some of my previous post (sorry i didn't mention that here) but when i bought my 73 240z, it looked like the previous owner did a hack job on the electrical, before i bought it ran perfect, he started it quickly, and never got a chance to see that the gauge wasn't working, he told me before he handed it over to me he had to remove the fuel tank to make a weld on the diff mount. then he remounted the tank and when i got the car back no wires were connected, so not sure what connects to what, i have see 2 wires coming from the tank, 2 wires coming from the fuel pump, a blue wire looking like it comes somewhere close to where the filler part of the tank is, and black, green and yellow wire coming from the top next to the chasis, so im not sure what connects to what, i looked at the wires coming from the sending unit and cleaned and theres no corriosion. as well when i connect the black wire from the fuel pump to the black wire that comes from top close to the chasis i hear the fuel pump run and constantly run (not sure if this should be another post, asking for help, as to why my fuel pump sounds like it constantly runs) \

so Escanlon, this is not a prank, really i am lost, if anyone can help, thanks

[EScanlon]

Raltz, the reason for my questioning your first post's validity is that many of the references you were making to wiring, parts etc. were similar to those that have been used by other prank posters to incite arguments and make members mad or angry. Even spammers try to sound "on topic" while just looking to spam. Trying to help either one of those is a waste of time.

To help you:

1) the Fuel Float Sensor doesn't have any wires coming out of it. It has a pair of "T" style connections that a locking spade connector connects to. One is the large size, the other is the smaller size. The two wires that connect to it are a Yellow and a Black. The Black is a ground connection.

2) the Fuel Pump receives it's power via a Green wire, and it's other wire goes to ground.

3) Have no idea what/where the Blue wire you have goes to. A WAG would be that it's the lead from the fuel pump that then gets the Green wire connected to it.

Get the wiring schematic for your year car and much of this will be much easier to trace and fix.

FWIW

E

Edited September 22, 2010 by EScanlon

[BrianL1987]

If the fuel gauge reads "full" the 2 wires on sending unit may have been attached to wrong leads (50/50 chance). Thats what I did (oops) easy fix if problem.

[biddljj]

Has the sending unit ever been removed ? I discovered my 72 240Z had a sending unit installed 180 degrees wrong. My sending unit had been removed to allow for gas tank restoration.

Jay

Not Just a Z - zdisease

[Bonzi Lon]

If, and when you remove the sending unit and it looks somewhat like this, you might consider replacing it. Cheaper in the long run, and don't forget to get a new O-ring to go with it.

Bonzi Lon