Need Help with 69 C10
 

Hi,

I've been a reader of this forum for the last six years since I bought my 1969 c10. In all those years my truck has run with no complaints so I never really needed to post.

Well now old blue is having some issues that have me stumped and I was hoping I could get some wisdom from this forum.

Here's the details. I was driving my truck one day after it sat for about a month and it started dying at every light when I needed to stopped.

After a few lights of having to start it, I got worried about getting stranded with a dead battery so I turned around and went home.

When I got home I noticed the fuel gauge read below Empty, so I figured "it's dying because it's out of gas." No problem, I took some gas out of the shed and started to fill up the tank. Almost immediately it overflowed out the filler neck.

At this point I was stumped. The fuel gauge reads empty, but the tank overflows. I moved the bench seat forward and started tapping on the tank and it sounded hollow/empty.

Other details. My truck has three tanks, but I've only used the cab tank since I purchased it. Also the sending unit in the cab tank only has one tube coming out.

I had to call my dad to borrow his s/10 this weekend in order to pickup a christmas tree. The tree barely fit in that tiny bed.

Thanks,
Adrian

Re: Need Help with 69 C10
 

Look for a tank switch on the floor between the drivers door and seat. If found what position is it in. If not found look for one in an other location. Sounds like a switch is on one of the axillary tanks, not the main tank and the main tank is full.

Re: Need Help with 69 C10
 

Thanks for the quick reply. I forgot to mention that I checked the tank switch and it's currently set to the main tank.

When I tapped on the tank it sounded hollow even through it overflows. Is it possible there's a bubble trapped in there?

Re: Need Help with 69 C10
 

I do not think you can tap a tank to see if it is full or not. I have a 200 gallon heating oil tank on my house and I have tried full and empty, but do not think it is possible to gauge the amount inside by tapping.


Here is a link to a straight forward method to test a fuel gauge. http://www.6066gmcguy.org/Electrical-02.htm

Check the fuel line coming into the carb and see if it has fuel. My 60 GMC had a clear inline filter and it was pretty obvious when it did not have fuel.

I would guess your fuel pump may be causing the problem. Try pouring a small amount of gas into the carb and see if it will start and run for a few seconds.

Re: Need Help with 69 C10
 

My '87 had a similar problem recently. Saddlebag tanks, when the tank selector switch was in between right and left, it would stall whenever at a stop.

Re: Need Help with 69 C10
 

another thing you could look at is inside the carb. manually move the throttle cable on the carb while looking inside of it and see if any gas spits into the carb. if your carb is pretty old, the accelrator pump might be shot and need to have the carb rebuilt. that's what mine was doing....

Re: Need Help with 69 C10
 

I can think of at least 6 things that will cause your problem and neither of them is fuel related. Here's why. Your truck runs 30 or 40 MPH in between the lights but dies while at idle at the light. Fuel delivery is much greater at 40 than at idle so you are getting plenty of fuel. So here's my thoughts.
1.Vacuum leak
2.poor spark at idle
3.one or more cylinders is not firing, maybe just at idle.
4 Worn points causing retarded timing and slow rpm at idle.
5. carb float has tiny debris in the float needle causing engine flooding at idle.
6.float level too high causing flooding.

These are just a few off the top of my head. There are a few more that are more radical like worn cam lobes and timing chain. Leaky valves etc.

It would be nice if you would post a few details about the engine, trans, carburetor.etc.

Re: Need Help with 69 C10
 

You can check the tank with a broom handle/ stick or something . I with Vette Vet line of thinking.