andyvr4

I recently put in a new tank sending unit and fuel pump and clean lines and for some reason my gas gauge reads empty no matter what. Today I lifted the car pulled the plug out and turn on the accessories and the gas gauge went to full. So what I'm trying to figure out is why my gas gauge wont work I'm stumped on this I was thinking it was a ground but not sure we just did an engine swap from a 305 to 350 and it would be nice to know where all my grounding points should be and how many I should have because I'm not positive we attached all of them and I'm not seeing any loose straps so any help would be grateful I really like a gas gauge. the gauge work before we did the engine swap but then again we also changed all the gas stuff out so I'm wondering if it's something I forgot or with something that is not working correctly with the sending unit

andyvr4

Bump. anyone?

Joe Tag

iTrader: (4)

The sender wire must be pinched or skinned and grounded somewhere. The gauge defaults to full when there is no signal, so that is normal. Trace the pink wire from the plug under the rear seat to the tank.

Gumby

That bulk head connection to run the wires through the body can get crusty n funky, had to wire around mine for fuel pump.

John in RI

iTrader: (167)

+1 Sounds as if the wiring is connected properly, but not sure what happens if the signal wire gets grounded due to a chaffed wire; seems like a EMPTY reading is possible if that happens.

Was the sending unit plugged and checked BEFORE it was installed ?

Probably best to try and obtain/borrow another sending unit so you can plug it in and test watch the gauge work properly before dropping the tank to remove the one that's not workin' right.

I ask if you tested it first because I've witnessed a sending unit that didn't work due to a lack of good contact in the rheostat type thing that the float operates. Basically; when the float goes up or down it moves this "rheostat" and the rheostat sends a variable strength signal down the wire to the gauge.




It IS possible to bend the tiny metal tabs and open up this thing so it can be cleaned, but this obviously mean the tank has to be dropped so the sending unit can be removed again.

Good luck !

andyvr4

No sadly was pressed for time and didn't think to test it first. Should have. Is there a way to test it before I have to drop the tank? I really dont want to drop it but if I have to I will. Can I use a mulitimeter and see if its correct or not?

Gumby

Most people who do that, install an access door while the tank is down, GM didn't do it out of lazyness.

As that what happens, ya do all that work then end up having to go back in. much easier with an access door.

Joe Tag

iTrader: (4)

Things done properly are rarely accomplished through the easy path. I wouldn't hack a hole in my car to save a few hours. Honestly, how much time do you really save by the time you spend cutting the hole, cutting the sender unit lines and patching them back up? How often do you have to change a pump if you buy a quality one vs an airtex? Talk about lazy?To each his own.

rusty vango

the gas gauge ground is under the left rear seat.where the wiring comes thru the body. you will find it screwed to the floor pan. most likely, all you need to do is clean it and it will work for you.

Joe Tag

iTrader: (4)

While that is a common problem, the symptoms don't suggest it. The gauge would be reading full and remain unchanged when disconnected. The signal wire IS grounded somehow. Through a break in the insulation or a faulty sending unit IMO.

Gumby

Good luck with that, had my car over 13 years now and have had to go in 3-4 times, an access door saved hrs n hrs of un-needed labor.

And no one said hack, if you would take a hatchet to your car, that’s your problem, people install a real proper door that effects the car in no way.

Your just a neg nacy, when I made my hole, so many said " your car is gonna fall apart, you weakened the structure" then when I installed a rear STB I was told " there is no need for that, the structure is sound without it, there is no flex"

So a 10x10 door will make your car fall apart, yet that is no flex in that are to need a brace. AKA your talking out your *** like the rest.........

Joe Tag

iTrader: (4)

Before pulling the interior or the tank, unplug the connector again. Test the resistance from the black wire on the body side to ground. If there is no resistance, the ground is good. Test the sending unit side pink wire to ground for resistance. If there is none, the wire is skinned and grounded or a faulty sender. Test the pink wire on sender side to black on sender side. If none, one of three things. The tank is empty, the sending unit is faulty, the float is stuck in the down position.

Joe Tag

iTrader: (4)

I never said your car will fall apart, just that I wouldn't cut an access door to save a few hours.

You contradict yourself in the same breath with that statement. Saying you need a rear brace, but there is no flex in that area. Not going to debate it with you any more than saying I wouldn't do it.

powder white

i need help what is the fuel line size on 89 rs camaro in-and out

andyvr4

Ok I will try this this week and see how it goes thanks

Bradlyj8Z28

iTrader: (2)

Any luck?