The Stovebolt Site Forums The Shop Area Engine Shop th '58 swoon

i've got a '58 apache with a 235 that seems to lose fuel pressure after about 3 miles of running. i've checked all the obvious stuff. pump is delivering pressure, filter is good, lines are not too close to the engine to cause vapor lock. had the carb rebuilt a year ago.
after i got stumped i took it to my local shop and they couldn't find anything. and i trust these guys. i don't think the tank is too rusty, because the fuel is running clean and the filter isn't catching too much gunk. anybody got any ideas?

thanks

david krause

chicago

hey welcome to the "real shop" David!
just what does 'seems to lose fuel pressure' mean?
if it runs the carb bowl empty, then next question is: does this happen on level ground and is the tank full, or nearly so? "pump is delivering pressure" says you haven't really checked the fuel pump!

if it appears to run outta gas when you hit a slight up hill, or when you accelerate harder, and particularly when the tank is quite low, you have a worn actuator arm on the fuel pump or the rod that pushes it is worn excessively - pull it and take a look at the amount of wear - if you think the pump is good but there's excessive wear on that arm you can lay a bit of weld on it or on the pump end of the push rod - otherwise replace the pump and I'd bet yer problem will be gone - report back!

Bill

thanks for the advice. i'll give it a shot. for $40 it's worth it to go ahead and replace the pump. i'll let you know what happens.

dk

carb float stickin..??? or needle and seat...??? maybe some water or junk floatin or sinkin around in the float bowl too..???

You can do a simple test to check the pump. No sense replacing it if it's good.

Make absolutely certain it's not a spark problem then check the in-tank filter.

oh, and you say, "filter is good" . How do you know? Do you have an inline fuel filter? They can look good but be clogged. If you don't have an inline fuel filter, you'll need one. I'm betting that it's crud in the tank though. Let us know.

naaah, it's the worn arm on the pump - been there, done that - looks like it pumps fine as long as the tanks not real low and there's no real load on the engine, so when ya check the pump you're fooled - gotta take it out and look at the wear

we'll see what the response is to a new pump - if it's not fixed at least there's a spare pump on hand! but it could be the rod is worn too

Bill

put in a new pump, for 29.00 it was worth the peace of mind. it definitely increased the pressure. but i still have the same problem. runs well for 4-5 miles, then acts as if it's running out of fuel. new fuel filter, carb was rebuilt last year, so i feel good about the fuel system, will check the fuel tank strainer next. otherwise i'm stumped.

Check to see if the filler cap is vented.

Very good point Cletis!

If that gas tank cap isn't vented, it's like trying to pour gas out of a five gallon can with out an air hole. It comes out, but slow. With a vented cap, it will come out like out of the can with an air hole. And that's just about how far it will run with out air. With a full tank, it wouldn't run near that far because there is no room for air in the tank.

Joe

My wife actually imploaded two gas tanks on her Chevy Corsica before the service department at the dealer finally replaced the gas cap that was not venting. She had the same symptoms you discribe where it felt like she was running out of gas, so she would stop and put in more gas and was only able to put in a very little, since the tank was full. Then the car would drive good for awhile and then it would start all over again. Next time you lose power try removing the gas cap and see if you now get your power back.

i'll try that today. thanks for the info.

so, i've been busy, and i've been riding the bus. the gas cap was not the issue. this weekend i'll wrangle some time and pull the tank and double check the strainer. an interesting side note, since changing the pump, it actually takes less time for the truck to fail. i was getting 5 miles before, now i'm down to 2 miles tops.

My 61 was doing this same thing recently. With the help of the stovebolt forum crew, I found that it was indeed the strainer on the fuel pickup in the tank. Changed it out, runs like a top.

thanks for the tip.

On my 49 it was a clogged fuel line [rust],changed to rubber line,no problem.


Floyd

Im not sure about your 58, but my 53 had the same problem. I managed to crawl under it with a piece of wire and a cresent wrench. There was a valve that comes out of the bottom of the tank under the cab. I pulled it out and gas was only dripping, I stuck the wire in, got soaked in gas but never had the problem again. Good Luck.

I'd drain all the gas out of the tank, pull it, then flush and seal the tank.

Even if that's not the problem, it will be some day.. it's something that should be done with any vehicle 40+ years old IMO.

Since it actually starts and runs a few miles or so before it starts acting up, I wouldn't suspect a clogged fuel line, since if there was enough crud in the fuel line to stop the engine, it would probably run like [censored] from the get go.

Inline fuel filter between the pump and the carb is a must have, as well. If you don't already have one, get one.. if you've got one, replace it.

With a clean and sealed tank, a new fuel pump, and a fresh fuel filter in line between pump and carb you fuel system should be good to go.

You probably have crud floating around in the gas tank.. as gas is sucked out of the tank by the fuel pump, this crud collects and finally clogs the flow. When the engine is shut off, the crud floats away and flow is restored.

You said with the new fuel pump the problem actually got worse.. which makes sence. Increased suction would mean that crud gets sucked to the "clog point" faster.

Sounds like natures version of the old pingpong ball in the gas tank trick.