Fuel delivery problem......

[stallion85]

Ok here's the deal. This is a recurring problem so I will tell you what I have done and what is going on. So far I have replace my fuel pump, fuel filter and my carb was rebuilt about 3 months ago (Q-Jet).

When my truck sits for a few days it will not start, does not get fuel to the carb. It will crank over and not even think about starting. I disconnected the line directly to the carb and no fuel squirts out while cranking. I took off the fuel filter and ran some air through it and it was not clogged. I then blew some compressed air through the fuel lines back into the tank and through the line to the carb. Both gave me the impression they were not clogged.

Now here is the kicker, when I dump fuel into the carb to get it to fire she will start after a few doses, then run great and start right back up again??? WTF is going on??

Any help will be greatly appreciated

 

[sled_dog]

just sounds to me like the fuel lines are emptying out when it sits then the fuel pump needs to get going to suck up fuel. How long do you sit there and crank it? Maybe its like sucking water up a straw and right before it hits your mouth you stop sucking. Never dealt with such an issue, never had a problem getting fuel TO the pump. Maybe check out your pickup in the tank? Just cause its clear enough to get some fuel doesn't mean its not some what clogged.

 

[stallion85]

I was thinking it might be something in the tank? I was hoping not though. As for how long I crank on it, I would say almost till the battery starts to die, so a long time. Never been inside a tank before....

 

[sled_dog]

hmm thats really weird...

 

[stallion85]

Thunder,



I will look into that, The thing is though, No fuel pumps out of the line while disconnected

I guess I saw your reply, then you edited it. I will do what you have suggested. Sounds like it could be a big factor in my situation.

 

[Thunder]

Check your fuel lines for leaks all the way back to the tank. Look for rusted spots or brittle/cracked rubber lines. Even a pinhole air leak will cause the fuel pump to suck air instead of gas.

 

[diesel4me]

it might bee

Could the carb be leaking out the contents of the float bowl thru leaky well plugs in the base of thr Q-jet??..that would flood the engine while sitting,then have an empty float bowl ,and after much cranking to "de-flood" the engine,the fuel pump will have to "catch up" and fill the bowl again before it will start..A bad check valve in the fuel pump could do it too(assuming its a mechanical pump)as can the already mentioned hole in the fuel lines that allow air in,but leak no fuel-I've seen rubber fuel line hoses that join 2 peices of metal lines together separate inside and collapse at random,driving you nuts when you never know when it might act up--the stock paper gas filter had a small check valve built into it to help keep the fuel bowl full,and to somehow magically keep the gas in the carb if you roll it over!!

How does it run once it starts--does it start and stall,or start and run and drive ok after you "prime" the carb??--that will help pin down the cause..

 

[stallion85]

Once it is started it runs like nothing is wrong whatsover. It doesn't stall, hesitate, nothing? I think thunder had a good point with maybe sucking air through the lines due to cracked or holes in them. Or it could be what you have mentioned about the hose collapsing. I will look into both of them. Thanks for the ideas guys

 

[big pappa b]

Find out anything yet? I too have a similar problem. Seems like I have to crank and crank to get it to fire after sitting for a while or overnight but it runs fine once it's going. I'm thinking of dumping the gas tank and swapping in a fuel cell with new fuel line all the way. That will have to wait until we close on the house and I see how much money we have left.
Anyone have a cheap big fuel cell for sale?