constant gas flow, even with engine off?
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Junior User
Joined: Nov 2010
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From: Portland, Oregon
constant gas flow, even with engine off?
83 f250 460:
My truck wouldn't start a few weeks ago, but since I don't drive it regularly (and it's not licensed), I didn't mind.
So I finally was able to check for the filter maybe being an issue or something else (first decent day in Portland, when I'm not at work, in a LONG time).
Couldn't find any filters on the frame/fuel lines.
So I did the next logical thing in my mind. I disconnected the fuel line AT the carb, and checked to see if I had any pressure.
Thats when something weird happened. As I unplugged the fuel line, gas was POURING out of the hose. The engine wasn't on, and I hadn't turned it over in weeks.
Now, maybe I'm totally wrong, but I would assume that isn't normal. It would explain why my engine wouldn't stay running (super flooding).
What could cause that? A bad fuel pump? Being stuck open?
Keep in mind, I'm on a hill, nose facing down.
My truck wouldn't start a few weeks ago, but since I don't drive it regularly (and it's not licensed), I didn't mind.
So I finally was able to check for the filter maybe being an issue or something else (first decent day in Portland, when I'm not at work, in a LONG time).
Couldn't find any filters on the frame/fuel lines.
So I did the next logical thing in my mind. I disconnected the fuel line AT the carb, and checked to see if I had any pressure.
Thats when something weird happened. As I unplugged the fuel line, gas was POURING out of the hose. The engine wasn't on, and I hadn't turned it over in weeks.
Now, maybe I'm totally wrong, but I would assume that isn't normal. It would explain why my engine wouldn't stay running (super flooding).
What could cause that? A bad fuel pump? Being stuck open?
Keep in mind, I'm on a hill, nose facing down.
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Junior User
Joined: Nov 2010
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From: Portland, Oregon
I tried it with the battery disconnected, hypothesizing that maybe there was power to the fuel pump (?) but it didn't make a difference.
I'm going to try it again, this time tweaking the relays. Maybe they're making it stick open? Who knows.
I'm going to try it again, this time tweaking the relays. Maybe they're making it stick open? Who knows.
Posting Guru
Joined: Jan 2012
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From: Dallas, GA
83 460 so I'm assuming it's a mechanical pump and not EFI?
If your float valves in the carb are working properly it shouldn't matter if there is fuel to the carb. There is fuel there all the time when it is running and the flow is controled by the bowl floats.
Is it under pressure or just running out? More importantly does it develop pressure when it's cranking?
If your float valves in the carb are working properly it shouldn't matter if there is fuel to the carb. There is fuel there all the time when it is running and the flow is controled by the bowl floats.
Is it under pressure or just running out? More importantly does it develop pressure when it's cranking?
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Joined: Nov 2007
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From: Denver Metro Area, CO
I would next check for spark
Just like a toilet bowl tank.... Your house has water pressure all the time, the valve controlled by the floating ball on the end of the rod controls the flow of water into the tank.
Sounds to me like what Matt said - a siphon. Personally, I wouldn't consider that unusual or a sign of anything bad.
Since you obviously have fuel to the carb, I would check for spark... Pull a plug wire from a plug, insert a screwdriver into the boot, hold it near a good ground as somebody turns the key as if to start it. You should see a strong, blue spark.
Kevin - Some of these 460s have mechanical pumps, others - even carb'd ones - have electric. Looking up fuel tank senders for 460s is a big PITA for this reason....
Posting Guru
Joined: Jan 2012
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From: Dallas, GA
yeah I was trying to remember what they call it. I think it called the High Temp package or something like that on the 460's. Those had the electric pumps and the funky fuel transition right at the carb by the distributor.
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Posting Guru
Joined: Jan 2012
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From: Dallas, GA
found what I was trying to think of. It's called the Hot Fuel Handling package. There is vapor seperator just before the carb.
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Junior User
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From: Portland, Oregon
Thanks all.
It just sounded weird to me (as I'm not a carb person, I'm a FI person...in that I like that my Volvo is fuel injected..hehe).
I'm thinking, based on what I skimmed on here, what was said here in this thread, and what I found out at a local auto parts store, that it could be the fuel pump (mech) is gone or going.
So it's back to the truck engine compartment i go!
It just sounded weird to me (as I'm not a carb person, I'm a FI person...in that I like that my Volvo is fuel injected..hehe).
I'm thinking, based on what I skimmed on here, what was said here in this thread, and what I found out at a local auto parts store, that it could be the fuel pump (mech) is gone or going.
So it's back to the truck engine compartment i go!
Posting Guru
Joined: Jan 2012
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From: Dallas, GA
Huh??? I'm not sure what you read here that led you to believe it's a fuel pump problem!!!
You were asked it it has a mechanical or electric fuel pump so that you could run some simple tests to rule that out.
Based on your original post, you stated you disconnected the battery to remove power to the pump. Now you state the parts store has told you it's a mechanical fuel pump problem.
You need to run some basic tests to see where the issue is.
Or you can go to the parts counter and throw parts at it until it runs.
You were asked it it has a mechanical or electric fuel pump so that you could run some simple tests to rule that out.
Based on your original post, you stated you disconnected the battery to remove power to the pump. Now you state the parts store has told you it's a mechanical fuel pump problem.
You need to run some basic tests to see where the issue is.
Or you can go to the parts counter and throw parts at it until it runs.
Thread Starter
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Junior User
Joined: Nov 2010
Posts: 81
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From: Portland, Oregon
You were asked it it has a mechanical or electric fuel pump so that you could run some simple tests to rule that out.
Based on your original post, you stated you disconnected the battery to remove power to the pump. Now you state the parts store has told you it's a mechanical fuel pump problem.
You need to run some basic tests to see where the issue is.
Or you can go to the parts counter and throw parts at it until it runs.
Based on your original post, you stated you disconnected the battery to remove power to the pump. Now you state the parts store has told you it's a mechanical fuel pump problem.
You need to run some basic tests to see where the issue is.
Or you can go to the parts counter and throw parts at it until it runs.
Thread Starter
|
Junior User
Joined: Nov 2010
Posts: 81
Likes: 0
From: Portland, Oregon
83 460 so I'm assuming it's a mechanical pump and not EFI?
If your float valves in the carb are working properly it shouldn't matter if there is fuel to the carb. There is fuel there all the time when it is running and the flow is controled by the bowl floats.
Is it under pressure or just running out? More importantly does it develop pressure when it's cranking?
If your float valves in the carb are working properly it shouldn't matter if there is fuel to the carb. There is fuel there all the time when it is running and the flow is controled by the bowl floats.
Is it under pressure or just running out? More importantly does it develop pressure when it's cranking?
Thread Starter
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Junior User
Joined: Nov 2010
Posts: 81
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From: Portland, Oregon
As I understand it, if there is a mechanical fuel pump, it should be easy to see on the engine block. So far I'm not finding anything.
I find the lines that from from under the truck (from the tanks) to a filter/splitter (1 in, 2 out). That goes to the carburetor.
I'll be back in a second to see if the spark issue happens (its a little hard to do it by myself).
I find the lines that from from under the truck (from the tanks) to a filter/splitter (1 in, 2 out). That goes to the carburetor.
I'll be back in a second to see if the spark issue happens (its a little hard to do it by myself).
Posting Guru
Joined: Jan 2012
Posts: 1,410
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From: Dallas, GA
I hear that...
What I would suggest is start very basic.
Every engine needs spark and fuel...so start there.
See if you have spark, at the right time of cource...and see if you have fuel.
You know you have fuel to the carb...just don't know if you have enough of it (i.e. is your pump working)
Take the air cleaner off and look straight down the throat of the carb with a flashlight. Stroke the accelorator a couple time all the way. See if you have a good strong stream of fuel squirting into the carb.
If the truck has been sitting for a long time...check to see if it smells funky.
If you got gas sqirting in the carb...then that's a good start. Check that your choke is funcitoning properly as long as your there.
Next you would move on to see if you have spark.
Once you narrow it to fuel or spark...then you can further narrow it down to why one of those is not working.
If you feel it is flooding...not based on the fuel coming out of the fuel line, Then hold the accelerator pedel to the floor as you crank it
What I would suggest is start very basic.
Every engine needs spark and fuel...so start there.
See if you have spark, at the right time of cource...and see if you have fuel.
You know you have fuel to the carb...just don't know if you have enough of it (i.e. is your pump working)
Take the air cleaner off and look straight down the throat of the carb with a flashlight. Stroke the accelorator a couple time all the way. See if you have a good strong stream of fuel squirting into the carb.
If the truck has been sitting for a long time...check to see if it smells funky.
If you got gas sqirting in the carb...then that's a good start. Check that your choke is funcitoning properly as long as your there.
Next you would move on to see if you have spark.
Once you narrow it to fuel or spark...then you can further narrow it down to why one of those is not working.
If you feel it is flooding...not based on the fuel coming out of the fuel line, Then hold the accelerator pedel to the floor as you crank it
Posting Guru
Joined: Jan 2012
Posts: 1,410
Likes: 1
From: Dallas, GA
perfect!!! then you don't have a fuel pump problem. Good job, that's possiblity is eliminated.