Starts, runs, drives then dies (a tale of two problems)

[Mac2Night]

So, I just read a similar thread the GreatJustino posted this week, but some of my elements are slightly different (seemed suggestions for his situation leaned towards points and/or wiring issues) and I couldn't offer his post any advice by posting there (nor did I want to hijack his thread) so I thought I would ask for help in a new post.

So, my new-to-me '74 had been sitting for several years. It's the first EB I have ever owned with an electric fuel pump and I have no knowledge of their operating habits/temperament other than just electrically pumping fuel from the tank to the carb. Upon my first attempts at driving it wouldn't idle after started, just fire up then die. I figured it was the old gas so I pumped the old gas out (dark as honey but no real issues with rust or debris). Once emptied, filled with new gas. Replaced the carb and fuel pump filters, sprayed out the carb (didn't take it apart and rebuild YET). This all seemed to help so I tried driving it to work yesterday. Big mistake! I got 5 miles into my 7 mile commute when it just died like out of gas. After sitting for 10 minutes, she fired up and I turned for home (getting stuck in midtown Atlanta is NOT fun (have dealt with that situation in an EB before and Atlantans do not like to be delayed by a vintage truck it seems). Made it almost home and it did the same thing again. This time I raised the hood and turn the key into the "On" position. The fuel pump would kick on with the power flowing to it. I turned the switch off then on again and the second time I did so, the pump was not running. Waited a little while and it started pumping again and the truck fired up and I made it home. While it sounds like the electric fuel pump, I am wondering if anyone else has had a similar experience with one before so i can use that as a baseline.

My second issue that may-or-may-not be related is the manual choke the PO installed as well. The lever is all or nothing it seems. Pull it out and it closes the throttle plate, push it in and it opens all the way. This alone seems to have something to do with the idling of the truck as when the truck is first stared and I have the throttle plate open it won't start but closed it does sit and idle.

I am at a loss at this point. Similar situations and suggested fixes welcome.

 

[broncnaz]

I would suspect the electric pump is either going bad or something is blocking the pickup in the tank and the pump is working hard and getting hot and shutting down. Do you know what brand of pump it is? Old gas and long term useage can cause build up in the pump which doesnt help. You might also check to see if the fuel tank has any pressure or vacuum on it when the engine dies sometimes a bad gas cap wont allow air into the tank and that can cuase a vacuum which may make the pump work harder.
AS for your choke I dont think its related but it sounds like its working like it supposed to. Cold engine choke closed engine runs cold engine choke open engine is hard to start. Now that said its more of a tuning issue on how much choke is needed for cold starts. I can usually tune my engines and carbs to where I hardly ever need to choke the engine except when its really cold.
Maybe as you go through this bronco a little more it will start better.

 

[Mac2Night]

Update. So I bypassed the electric pump and put a new mechanical one on and it got worse. Not only did it start and run then die, I couldn't get it to run at all save for a shot of starter fluid and then it just died without really running more than 5 seconds. Thoughts here appreciated.

I would suspect the electric pump is either going bad or something is blocking the pickup in the tank and the pump is working hard and getting hot and shutting down. Do you know what brand of pump it is? Old gas and long term useage can cause build up in the pump which doesnt help. You might also check to see if the fuel tank has any pressure or vacuum on it when the engine dies sometimes a bad gas cap wont allow air into the tank and that can cuase a vacuum which may make the pump work harder.
AS for your choke I dont think its related but it sounds like its working like it supposed to. Cold engine choke closed engine runs cold engine choke open engine is hard to start. Now that said its more of a tuning issue on how much choke is needed for cold starts. I can usually tune my engines and carbs to where I hardly ever need to choke the engine except when its really cold.
Maybe as you go through this bronco a little more it will start better.

 

[blubuckaroo]

Try disconnecting your new mechanical pump from its suction hose and stick the hose into a container. Then pressurize the fuel tank with compressed air. Just a little pressure should give you a good stream of fuel from the hose.

 

[zonian]

Like broncnaz, I'm thinking making blockage in pickup. Maybe next step drop the tank and check it out...

 

[badmuttstang]

I'd say time to check fuel lines for blockage and or fuel tank for the same can you take a picture of the electric fuel pump you might be able to rebuild it for next to nothing but I'd say drop the tank and flush it out while its out disconnect the fuel lines both ends from carb and pump blow it out pump to tank and blow it out

 

[badmuttstang]

Blubuckaroo and zonian beat me to it while I was typing but yes that's where you need to go next

 

[Mac2Night]

So I worked on everything tonight. Ran a bottle of gas from the pump hose and she started and ran beautifully... BUT when I even lightly touched the accelerator, it sucks and dies. It almost sounds like a vacuum leak sucking but I checked and then checked again and couldn't find a leak. After it dies it is hard to start OR it won't till it sits for awhile.

Suggestion on what it might be

 

[blubuckaroo]

You say the car sat for several years? Flushing out the carb might not be enough. The diaphragm material on the power valve could have decayed, causing a lean condition like you've described. Why not just kit the carb? That way you'll eliminate needle valve, float level and accelerator pump problems from your troubleshooting. All for the price of a kit and can of Chemtool.

 

[broncnaz]

Have you rebuilt or checked all the adjustments on the carb? If not Probably should go thur the carb. Id also check and make sure the accelerator pump is working that could be a partial cause of it dying when you touch the throttle and the hard restart. But really Id go thur the carb and make sure its clean and adjuster properly.