fasteddi

iTrader: (2)

Last weekend i put white guages in my car and i took the cluster out to make it easier.. Well in the last few days the fuel guage is reading that i have more than i really have. It goes up and down as i put more gas in it but its off like a 1/4 of a tank. What did i do to this thing???? Any help would be great.

fasteddi

iTrader: (2)

I was thinking that mabey I got the back of the cluster dirty or something when it was off... would this affect the reading since its not stuck. Isnt 90ohms what the max is for a full tank???? So if i got it dirty it would have greater ohms than the sending unit is sending?? Its just a though.. thanks anyone!

t-top havoc

iTrader: (3)

Your new fuel gauge worked correctly until recently?

Ours is about 1/2 tank off, but I was told we need a new sender.

Maybe the sender is going bad Or a bad connection at the gauge itself?

fasteddi

iTrader: (2)

well it must of been the connection when i put the cluster back in. because tonight i was woundering that mabey i should hit the dash a few times, because i didnt have time to take the cluster out again, and the gauge was really innoying me!... well as i hit it (gently) the fuel needle started to go from 3/4 tank to 1/2 tank, which is were its suppose to be. I think the connection was the problem, so I think... its fixed... thanks anyways though.

Project 3.4 Camaro

Probably was the connection, the connectors just get pushed onto, there isn't really a clip of any type to secure it.

55ChevyMan

I have brought a Iroc z stock speedo from ebay and the gas goes all the way to the very top when I started it, it a Lt1 swap and I had also put a new fuel pump and keep the old sending unit could it be the fuel gauge are the fuel gauge connection in the dash I dont think it the sending unit

fasteddi

iTrader: (2)

the fuel gauge connections in the dash are on the back of the gauge cluster. The connections look like a computer plug. To check the sending unit, you un hook the wires coming from the gas tank, which will have a pig tail and stick a bent paper clip in the pig tail going to the front of the car, the gauge will read EMPTY, if the sending unit works. If the guage doesnt read that way, then your problem is the sending unit in the tank.

55ChevyMan

thanks for your help I will try this tommrow now the gas gauge point way passed full even when the key is off

fasteddi

iTrader: (2)

well just try the paper clip thing connecting the two wires. the basic opperation of the gauge is by how many ohms/resistance the sending unit sends to the cluster. I think its 90 ohms when its full. so if the gauge reads full and you tank is not full then you have too much resistance somewhere, such as a faulty sending unit or a bad connection somewhere.

55ChevyMan

Tried the paper clip no defference it didnt move it pointing stright up to gas pump on gauge, connector wire going to the front it has 3 point connector I put the wire clip one end on right and one end on the left maybe I will try taken the plastic cover off and move the gauge needle down and see if it stay down right now it seem like it the gas gauge that bad are bad conection may be put some dielectric grease
on connector thanks again for your help

55ChevyMan

86 IROR Z if its disconected from the fuel pump why would it go up all the way today I removed the gauges and clean conections put some dielectric same thing I think the problem is between the gauge and the pig tail conector could it be a loose ground ?????? thanks no not a loose ground

fasteddi

iTrader: (2)

what year is your car??? On mine, 1991, the back of the gauge cluster is a pin style. Baiscally what a computer pin hook up looks like. That may be loose or have a corroded connection. Here is how my gauges work... My sending unit sends a signal in Ohms. From 0 to 90 Ohms. 0 means the tank is empty and 90 means its full. If your have a bad connection the signal will be a higher Ohm. Thats why your gauge is reading so high. If you connect the wires on the sending unit on the side that goes to the gauges, it will read empty beacuse the Ohms is very very low. Low Resistance. Check the back of the cluster and see if its dirty and also the wire running from your sending unit to the dash are... But your car may be older and the set up might be different than my 1991.... ill look it up later today

fasteddi

iTrader: (2)

OH yea.....IF you removed the pig tail from the sending unit in the tank and the gauges still read full then your problem is could still the sending unit.. look at all the connections on the back of the cluster... and the wires that run from the cluster all the way back as far as you can find them....

55ChevyMan

there two nuts you can tighten it shouldnt move at all

fasteddi

iTrader: (2)

it shouldnt move but they can be dirty or corroded.... its just a thought

55ChevyMan

[quote=fasteddi;5027211]it shouldnt move but they can be dirty or corroded.... its just a thought[/quo On the wires coming from connector pig tail there ( Pink sending unit) ( Tan/white fuelpump) ( Black ground) when I ground the pink wire it starts working the gauge starts coming down to around a 1/4 of tank which is about right I thinking it a bad ground wire the wire looks good like new under left rear seat if dirty I think, it by the pig tail connector black ground wire I dont know what to use to clean it any ideas W D40 are maybe brake clean

thanks for your help

fasteddi

iTrader: (2)

wd 40 should work. Where did you connect the pink to the ground at?? If it was at the sending unit then you completed the circit and the gauge should have read empty.. so your wiring probly is dirty.. just clean it as best as you can and see if theres a difference

fasteddi

iTrader: (2)

you could try a finger nail file too i guess.. emery board ... be careful though.

55ChevyMan

I tryed grounding the pink wire just to the body I dont know if adding a ground there would work long term are not

fasteddi

iTrader: (2)

was the gauge reading what it should??? you grounded the pink coming from the front of the car??? I found this on TG.org >>>>>>

The way the fuel gauge works is some what like a game of electrical tug of war. Without getting into too much detail on that basically how it works is as the resistance increases so does your fuel level according to the gauge and vice verse. What 99.9% of the time causes your issue is an open circuit. This makes scene because an open circuit is essentially infinite resistance which would correspond to an infinitely high fuel reading (pegged). The opposite would be shorting it to ground with the paperclip trick mentioned earlier makes the resistance 0 and the fuel level should also read 0 indicating the gauge itself works. To troubleshoot this I would start at the gauge itself. I would remove the fuel gauge and measure the resistance to ground of the contact that connects to the fuel level sensor. Now your meter could show a multitude of things or just nothing at all. If the meter is unresponsive this means you have an open circuit and will need to track it back. Could be a bad connection a broken wire bad sender ect. If you get any resistance withing the normal range of the sensor (including 90 ohms) it means that either the gauge itself has an open circuit internally, a bad connection from the dash to the gauge itself, or in case of some constant high reading around 90 the sensor may be just jammed up.

55ChevyMan

Now the 3month old fuel pump is not working no fuel pressure

fasteddi

iTrader: (2)

jezz well sorry to hear it... it suxs taking out the fuel pumps on the thirdgens.

fasteddi

iTrader: (2)

mabey check out those wires that run into the fuel pump... mabey you losened them up when you were checking the sending unit??? just a thought...

55ChevyMan

I put in a new fuel pump about 3 months ago driven the car under 35 miles what a pain dont know if chaning the fuel relay would help

fasteddi

iTrader: (2)

mabey its the relay... did you run the tank dry? I know that will kill them... the relay should is on the firewall on the drivers side.. i hope thats your problem.. its easier and cheeper.. only like $8. I replaced mine like 6 months ago.

55ChevyMan

Well on my new lt1 harness it has the new smaller relay better then the old ones when i went to auto zone and they want like $48 dollars so tommrow I will go to salvage yard I used a test light and the wire going to the fuel pump brown and there no power there so maybe it is a relay the only fuse by the battery box I found was going to the accel coil it was a 10

fasteddi

iTrader: (2)

jezzz 50 bucks!! ya good thinking going to the junk yard for sure.. itll cost little to nothing if ya find one out there. Hope you find one and fix the problem

55ChevyMan

If this happen to you there no power to the relay so every one said fuel relay is by the battery looked and looked and I cant find took the battery then look on the left side and here it is blown 20a fuse change it I think fire birds battery goes on the left but if you have a(( 86 Camaro it on the Left Side fuel relay fuse) not by the battery( I say thank you every one for your help

fasteddi

iTrader: (2)

awsome that you found the problem... i keep your situation in mind if something like that ever happends to my f-body