Hi, I have a 1986 Ford E350 with a 460 4bbl.
My problem is that it stalls after accelerating and lifting the gas. My pressure gage bounces between 2 and 7 psi. Should it stay steady? Any help will be appreciated.
Jim

 

my gauge bounces with the mechanical pump but it doesn't fluctuate that much when it works properly.
2 is low, it should be right around 5-7 . (gauge tolerance and all) Hard to say which pump is the issue though, if it's mechanical only that narrows it down.
If you have in tank pumps I don't know since I have yet to own one with those pumps. I think the in tank pumps are only 5 psi. the mechanical brings it up the rest of the way.
Do you know if you have the in tank pumps and mechanical or only mechanical?

 

Dusty I dont think the 460 or any of the motors used both motor driven and tank pumps at the same time.
It was either a motor driven OR tank pump.

What you may be thinking of is the early EFI trucks first had a in tank lift pump and then a high PSI pump on the inner frame rail.
Later EFI then only had a high PSI in tank pump no rail mounted pump.
No 460 in the 80 to 86 were EFI but maybe the later had in tank low PSI pump?

The other thing to think about is the HFB hot fuel bypass that I think the 460 had.
But in any case the fuel psi dropping to 2 psi is not a good thing.

Is this bouncing at idle just sitting or when accelerating or when you let off and it then reads steady?
When it stalls how hard is the accelerating? Foot to floor and it shifts to 2nd gear and you let off and it stalls?
Or you pull from a stop like normal and someone starts to pull out in front and you left off the throttle?
Out of gear when is the idle speed and if you give it throttle and let off will it stall then?
What carb you running and when was the last time it was rebuilt?
Dave ----

 

Bouncing should not affect how it runs unless it stays low for a extended period of time. The carb has two storage bowls for fuel. That being said, if it's staying down at 2psi the whole time you are accelerating, you may indeed be using up the fuel in the carb fuel bowl if the fuel pump is not replacing it.

I would be curious to run it hard till it stalls, and then do not restart it but pull to the side of the road and check the fuel level in the front bowl in the carb. Those carbs usually had site plugs in the side of the bowl. You could stick a small piece of wire down in the hole after you take the plug out and see where the fuel level is. It should be near the bottom of the hole.

 

Greetings! I have an E350 too, with carbed 460 and C6 automatic transmission. Other features include(d) an electric in tank fuel pump (since converted to an external electric fuel pump), stock Holley 4180 carb, with the hot fuel handling fuel return line.

For what it’s worth, I’m not sure what you mean by “it stalls after accelerating and lifting the gas”.. which suggests it runs fine under throttle and only quits when you come off the throttle? It would also be helpful to know if you have an automatic or manual transmission, electric or mechanical fuel pump, stock or replacement carb, and if you have the hot fuel handling system / return line still intact.

I replaced the original in tank fuel pump after I started running out of gas pulling hills under heavy throttle. It would start cutting out while my foot was on the gas… but as you describe it happening after “lifting the gas” your problem sounds a little different? The old pump still worked but the flow was too low to keep up with the demand from the engine. The tired old pump would only flow about 1/4 gallon per minute at 1 or 2 psi which was not enough. The new one (and spec) flows about 1/2 gallon per minute at about 5 psi.

You might check to see how much fuel flow you’re getting (you want about 1/2 gallon per minute) and see if you can tell us a little more about the problem and how your vehicle is equipped.