The clothes pin trick works well on just about anything. I have used it many times for diagnostic purposes, not permanent though.

 

I got the spacer and coil installed and my symptoms seem to have gone away. I think the test will be when it warms up outside though as it was only in the mid 40s today. Might be a while until its in the 70s again which is the temperature when I had a lot of issues the last time.

 

I took it for a spin today and it seems like my issues aren't sorted out yet. It stalled on me again, though it was not as bad as the last time. It was not as warm today either, so I am not sure if the issue has actually improved or not. I never checked my float levels, so that will be my next step.

 

I did little more digging. I used a temp gun to figure out where my hottest area is in my fuel system. The fuel pump was as high as 135 degrees, and it was only in the low 30s outside today. the fittings at the carb were all around 100-105. Do you guys think that the temperature at the pump is high enough to cause vapor lock? It stalled on me once today, and when I pulled over and checked the float levels, the front was actually too high. The engine did spin for a while not running before I pushed the clutch in, so I am not sure if that could have overfilled the float bowl. I checked the bowls afterwards when it was running, and they were both set perfectly. At this point, I am leaning towards the fuel pump getting too hot. What do you guys think?

 

Have you tried running with the gas cap off? As previously suggested I think your system is either creating a vacuum in the tank or clogged with dirt.

 

Remind me. Is your fuel pump stock? or is it an aftermarket electric frame mounted unit?

Sounds like at least you have fuel in the carb. Fuel expands when it gets warmer, and that could cause it to percolate, thus maybe pushing the raw fuel in your bowls up and over from the main well of your carburetor into your intake manifold. The raw fuel dripping from down inside your carburetor causes flooding, which would necessitate you using the carb's unloader mechanism, by flooring the accelerator while you are cranking to hopefully lean out the mixture while at the same time pumping the overly rich mixture out thru the exhaust. I know you mention that your fuel pump measured around 135 *, my 302 has high temps under the hood. I have looked at my stock block mounted fuel pump temp before too, IIRC it was around the block temperature of 190 degrees with no hot run and very minimal hot start issues. When cranking in warm weather, I just have to let it spin for a second or two, then gently push down on the accelerator about 1/2 way and it's running. I guess I would think if you have fuel in the carb bowls, then the mystery moves to the lack of spark. I would take along one of those spark testers, a mechanic's remote start button, some chocks, and test it for spark next time it quits, hopefully on a quiet stretch of highway. Sorry if you checked for spark already!

PS, Try what Pete has mentioned above. If you are using a stock tank, hopefully you have a vented fuel cap.

 

If you rule out ignition system problems, one thing about running a rear mounted tank with a mechanical fuel pump, is to make sure the fuel line from the tank is adequately sized. I'd think with a 429, the line should be 3/8" to be on the safe side. Remember that the pressure in the line will be reduced because it's on the suction side of the pump and if the line is restricted, the pressure will be much less toward the front of the rig since it's nearer the pump inlet. The more the pressure drop across the line, the more likely the fuel is to boil up front nearer the engine. Fuel pumps are designed to pump liquid (not vapor) so any heat from headers, collectors, catalysts, etc. that are near the fuel line will aggravate the problem, as will running at higher altitudes. Years ago, I had a "Hot Rod" Ford with fuel starvation problems and symptoms of vapor lock. The local "old timers" suggested wrapping the fuel line to the carb with aluminum foil, putting clothes pins on the line, etc. - none of which did anything to help. It turned out that my dual side exhaust pipe was running too close to the "undersized" stock fuel line and that was the cause of the vapor lock. Once I happened to notice that (with the car up on a lift) it was obvious what had been causing the vapor lock. In my case, I only experienced the problem in hot weather and while pulling long hills in the mountains - fuel demand was greater, exhaust was running much hotter, and the higher altitude was reducing the boiling point, too. It probably wouldn't hurt to do a pressure and capacity test on your pump just to make sure you don't have mechanical problems with it. Is the fuel pump eccentric on a 429 attached to the cam with just one bolt like on the old FE's? I saw one of those come loose once and the fuel pump couldn't do it's job as a result. Replacing the fuel pump didn't much help either! - Bob

 

Hey Nick,
You've tried some of the easier fixes....but the problem persists.
You may want to add the gas tank vent at this point ..... It's a fairly straight forward
job & the vent costs less than $10. Not much fun lowering the tank but would rule out
venting as a problem. (We had a vented gas cap & a Mustang tank --- experienced similar problems
until we added an additional tank vent). Sorry about your frustration - these old trucks can be a pain).

Ben in Austin
1950 F1 (351W/AOD)

 

Atmospheric pressure is 14.7 psi (at sea level). This is the pressure exerted on the surface of the fuel in your tank. The tank vent system must be of adequate size to compensate for fuel used without reducing that pressure, or worse, creating a vacuum which could, in effect, starve the fuel pump. This is reaching.........

 

Can you describe just how it dies? Is it all of a sudden? Are you getting back fire from the exhaust? Or popping from the carb? Or does the engine shake and surge like its going lean? BTW, Bob had a great write up on how fuel line size, length, and heat all effect each other. I learned a lot from that. And all posts in this thread!.

 

I have not yet tried that. I will give it a shot next time I take it out. We are currently getting a bunch of snow, so it will probably be a little bit before I can get it out again.

 

I have an edelbrock mechanical pump
Fuel pouring over into the inlet is what I was leaning towards. I pulled the needle and seat out to see if maybe it got fouled, but it is clean as a whistle. I also pulled the bowl to take a look at it and that looks fine too. I think Im gonna take a timing light with me next time and see if its getting spark after it stalls. I do jave the stock vented cap.

 

I have 3/8 stainless line running from the tank to the pump, then a -6 an line from the pump to the carb. I checked all the way down the rail where thw exhuast is closest to the fuel line, and it was cool to the touch when I had it running for a while yesterday.

 

I dont have a floor yet in the bed, so adding a vent wont be a big pain. I think Im gonna try running without the gas cap and see if that helps, then Ill know if I need to add a vent.

 

I dont really have enough experience to say that its leaning out or getting too rich. When it stalls, if I hold the throttle open it pops pretty bad, and it trys to run if I pump the throttle. If I let off the throttle it dies completely.