Jump to content

Fuel Control Valve Test


radio9phs

Recommended Posts

I have been reading many posts about the fuel control valve, its function, necessity (or not), and proper connection.  I have a 1976 that runs fine, despite the fact that according to prior posts, my lines are not connected properly.  My valve also appears to be a mirror image of that shown in parts diagrams.

 

This makes me think that the lines are in fact connected properly, or that they are not, but the valve is not functional.

 

I want to test the valve.  I am thinking I can inject fuel through the various (disconnected) lines with a syringe or something with and without vacuum applied by my Mighty Vac.  If is in fact nonfunctional I will delete it as many others have done.

 

Anyone done a test like this or have some other method of testing the Fuel control valve?

 

Paul

post-42201-0-18776900-1374181051_thumb.j

post-42201-0-44096300-1374181065_thumb.j

Link to comment
Share on other sites

You could just remove the thing and fling it into the weeds as so many others have done.  It looks like you could also remove two pieces of fuel line, which since they are degradable will make your car safer.  I'm all for maximum mechanical simplicity.

Link to comment
Share on other sites

You can test it with air and the results would be the same as with fuel. Or you can just remove the hose to the tank and put a short hose from that nozzle in a container, run the engine so the fuel pressure comes up then when the engine is shut off a small amount of fuel should vent to the container.  Based on my tests, the circuit that vents to the tank is the valve to carb side.  That releases pressure above the float needle so in hot weather the bowl won't continue to fill if fuel in the bowl boils off.

 

Throwing it in the weeds may give you hot start flooding if you don't have it now.  Your results may vary.

Link to comment
Share on other sites

I don't see any difference between your valve and mine, or the connections thereto. My fuel return line, running between the battery and the radiator in the accompanying 1983 photos, had a check valve, now gone. A line runs from the fuel pump to the valve, and another from the valve to the carb.

Steve

post-41123-0-43634200-1374209667_thumb.j

post-41123-0-05122000-1374209762_thumb.j

Link to comment
Share on other sites

Unless you live in California and it's a '76, that whole wretched mess is a candiate for CD's neighbor's pool.  Just more lines to leak either fuel or vacuum, and provide running problems at inopportune moments. 

 

I yanked all that stuff off my '73 back in 1979 when I replaced the Solex carb with a Weber, and haven't had any problems with vapor lock or hard hot starting.  Just keep the fuel lines away from the cylinder head (don't let 'em touch) and you'll be good.  One caveat; if you disconnect the grey charcoal canister in the engine compartment from the metal vapor line that ends under the battery, be sure and plug that line at the fuel tank end.  Otherwise, it'll siphon fuel when the tank's full.  Ask me how I learned that about 25 or so years ago.

 

mike

Link to comment
Share on other sites

Tonight during a pleasure drive, began to encounter significant engine stalling, like a fuel starvation issue. I limped home, and started to investigate. Fuel pump OK. No significant rust coming out into carb. I finally decided to test the fuel return valve. I undid the line coming from the valve returning back to the fuel tank, put the end in a jar, and started engine. Lots of fuel pumping out. I switched ports at the valve, and again lots of fuel coming out. Both tests with vacuum line attached. This makes me think the valve was dumping more fuel back to the tank than was going to the carb.

As had been previously suggested,and as many others have done, I removed the valve completely, and plugged off the end of the fuel return line. No more fuel starvation issue during rest drive.

Link to comment
Share on other sites

Not much pressure is needed at the line to the carb.  The carb fills just like a toilet tank does.  When the gasoline is sucked into the engine, the float lowers and more fuel spills into the bowl just like a toilet when the water goes out of the tank when the handle is pulled.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Upcoming Events

×
×
  • Create New...