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gas gauge goof

Kain

Kain

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I went to the lake last night with some friends. while i was waiting to pay when I hit the brake pedal the gas gauge would go to empty and stay there.

I was going to pull the gauge cluster and check the grounds cause i know they both work of a ground connection. is there anything else i should look for besides the printed circuit board and bad grounds?:dunno:
 
I would check the ground near the gas tank first, simply cause it's easier to get to. The brake switch deals with sending power to the tail lights, not ground. And normally, if there is a ground issue with the gauge cluster, all the gauges are dead since it shares a ground on the driver side A pillar.

Might be frame ground near gas tank or dead gauge. Then again, I tossed all my dash related stuff pretty quick so I'm just guessing.
 
well what gets me is it was in park so it was not moving but hit the brakes and the gauge went to empty. I did check the wire from the firewall to the tank and there is no breaks in the wire and it was connected. and the ground at the sending unit is good.
 
These gauges are not the best, and they do weird things when they go bad. I'd try another gauge first...
 
Maybe the wire from the gas gauge to sender unit is getting pinched by the brake pedal linkage ?...it passes thru the firewall right near the same spot..
 
Disconnect sender wire near tank. Watch gauge as you disconnect the wire, then ground the sender wire to the frame. If no change in gauge reading, problem is forward of that connection. If the gauge changes when you do both tests, the problem is in the tank, or the tank ground.

If it's an open or short to ground, gauge will go well past full or empty. If it's not doing that, something else is probably wrong.
 
Well i will check that when my brother gets off, fallowed the sending wire all the way from the tank into the
Firewall to the fash gauge cluster and cant find a bad spot

He sending unit is only a few mounths old.so i hope thats not it.
Its a pain in the but to change.
 
Well i took the sending wire to the tank loose and it went way past full
My question is the sending unit bad again?
 
Now take that wire and ground it. If it goes past empty, the problem is something with the tank or wiring to the tank. The tank ground is the most common problem IF you do the test and find the gauge responds correctly when grounded.

FWIW I don't think the "mid point" of the gauge reading means anything. I've never seen a gauge that was correct on either end of the scale, but off in the middle. May happen, just isn't common, at all. Gauge failure itself is not common at all. It's almost always a wiring/connection/sender issue.
 
ya it the sending unit again, after i did that and hooked it up the guge needle waved at me
 
No fun, but you can always drop the tank and test the sender once you remove it. Have to drop it anyway right? The senders aren't really complex, the wiper or wire connection(s) are the only things that should go wrong, unless the float breaks off or something weird like that.
 
I was stupid,and didn't test the sending unit when I installed another tank in my '82 K2500 diesel on the drivers side..

--I put the original one back in ,which I had never had hooked up before (truck had dual tanks,and I just ran it on one tank on the right side,all the wiring and switch for the dual tanks was butchered or missing)..I assumed it would work fine..
I ended up having to extend the wires from the right side tank to the left--then after it was all installed,the frigging sending unit proved to be junk-:mad:..-gauge pegs the needle way past full...:doah:

I confirmed it was the sending unit by plugging in the other one that worked that was in the RH tank...move the float up and down,and the gauge responds correctly,so its not the wiring...of course!..:doah:..that would be too easy a fix..
:mad:..so far I've resisted dropping the tank and went back to the old method of writing down the mileage every time I put fuel in it,and how much..

I have at least 3 working sending units salvaged from gasoline powered trucks,and one brand new one never used--but I balk at using them in my diesel,I'd lose the "water in fuel" sensor ...but at this point it'd be better than guessing how much fuel is left in it..the water in fuel feature probably doesn't work half the time anyway...
 
dyeager535 said:
Now take that wire and ground it. If it goes past empty, the problem is something with the tank or wiring to the tank. The tank ground is the most common problem IF you do the test and find the gauge responds correctly when grounded.

FWIW I don't think the "mid point" of the gauge reading means anything. I've never seen a gauge that was correct on either end of the scale, but off in the middle. May happen, just isn't common, at all. Gauge failure itself is not common at all. It's almost always a wiring/connection/sender issue.
Click to expand...

Kain said:
ya it the sending unit again, after i did that and hooked it up the guge needle waved at me
Click to expand...

I'm missing something here...did you check whether your sending unit is actually getting a good ground connection? Your sending unit may be fine...
 
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