79 C10 350 No fuel -- replaced pump and still nothing

[brody287]

Hey guys, I've got a 1979 Chevy C10 with the 350 SBC and dual tanks. The dual tanks have worked beautifully ever since I bought the truck two years ago, no problems there at all (except for a leak in the right side that has been fixed). It's got cold here in Canada and the truck was having some trouble starting last week. No problem, I gave it plenty of time to warm up. I should say more specifically, it would start up fine, but the problem was keeping it running. It would shut off and then only brake cleaner would get it going again. Odd that it would start fine with just a few pumps of the pedal the first time, and then require some brake clean afterwards. And it has never needed brake cleaner before. Even on the coldest days.

Mind you, I'm saying it's cold here. It's about freezing, 0C most mornings. This truck has easily started at -30C before. Few pumps and foot on the gas and she's good to go. So this has been really strange behaviour.

Then the other morning, it started up fine, died as usual, and never came on again. Even with brake clean. I tried again later that afternoon and it wouldn't start. So I got to work testing things and disconnected the fuel line. No fuel was coming out of it when cranking so I figured that was my culprit and bought a new fuel pump.

I installed that today and still nothing. And it's not like I haven't been cranking it for a while to try and get it going. What is going on here? And it still won't start even with brake clean. Which should be my indication that it's not the fuel, or at least not just the fuel. It should definitely fire off at least on the stuff, and it's not even doing that.

So I'm at a loss here. I don't know anything about the switching system for the two tanks. But I'm starting to suspect my problem may be further back with that system. How do I test it? Any suggestions for me on this one? Or is it something else other than the fuel entirely? But that wouldn't explain no fuel from the pump...

Any help is greatly appreciated.

[dusterdude]

I would run a hose out of a gas can to the inlet side of the pump and see if the pump will pick up gas out of the can.that will tell you whether or not its a supply issue.

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[bd]

Verify ignition spark while cranking before chasing that rabbit too far into the woods.  Pull the most easily accessible spark plug wire off of its spark plug and slide the boot up the wire far enough to expose the terminal.  Keeping your hand well away from the business end of the wire, hold the spark plug terminal about 3/4" away from a bare metal ground and crank the engine.  You should see a bright blue spark arc the gap.  If not, resolve the ignition problem before tackling fuel delivery.

[JohnnyPopper]

Once you've verified spark, do bd's trick of looking down the barrel of the primaries with a bright light as you pump the throttle, looking for gas sprays from the accelerator pump.

If none, pour a couple of ounces into the vent tube at the front of the carb to fill the bowl, see if it starts.

Being so cold though, how is your choke acting? Sounds like it got progressively worse- as in harder to start.

The choke should close completely at those temps.

[brody287]

I verified spark and then filled the bowl down that vent on the front of the primaries. She fired off so hallelujah I know it's gotta be a fuel issue. After that I ran a hose straight from the pump into a bottle of gas and it ran on that, so, the fuel pump works. The old one probably did too but hey I don't mind having a shiny new one on there.

From there I moved back to the selector valve for the dual tanks and and bypassed it with some more fuel line. It works great now! So the tank selecting valve must be shot. I'm back on the road just down a tank. Thanks guys! I got to a point of being exasperated because it's my daily and just needed some ideas. Thanks again.

[dusterdude]

Excellent!!!

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[JohnnyPopper]

Nice, glad it worked out 

[Mike81K10]

I have had my tank selector valve gum up with crud. Remove it and check the inlets and outlets. Connect wires to operate it with a battery to test it out. You can clean it up if the inlets and outlets are clogged and reinstall. The new selector valves out there are not as good as the OEM (which is no longer available). Might want to check out your tanks while you are at it. Ethanol plays havoc on the older vehicles and the steel tanks rust up pretty bad (ethanol causes rust to occur in the older fuel system).