Runs out of fuel…

[BJedi76]

1986 GMC 1500 Sierra Classic 4x4 SWB w/Q-jet 305”/700R4

I rebuilt the Q-jet (I didn’t replace the 2 (throttle butterfly) seals on housing

I have to prime the carburetor or spray starter fluid on air cleaner to start it. It takes a few tries.

Once it’s running, I can turn it off and it will restart just fine. If I start it every day, it will start just fine, but if I wait two days or more, I have to prime it again.

… also I can’t even make it around the block if I drive it. It runs out of gas.

- new (in tank) fuel pick up/sending unit w/new fuel sock.

- New fuel filters (in carburetor and in-line before fuel pump)

- New fuel pump

- New steel line from fuel pump to carburetor

 

[BJedi76]

Ok

 

[80BrownK10]

Are you sure the fuel pump is good?

 

[BJedi76]

No

 

[Paladin]

Ahhhhhhh..... another thread involving a vehicle not wanting to stay running with the Wonderful, Glorious, Magnifcent Q-Jet...! Isn't that a complete surprise, NOT!!! Now shall come all the responses of people who haven't learned from history!!!! LOL

 

[Octane]

How exactly would you test whether the “fuel pump is good?”

It starts, runs, & revs, and it will idle until i turn it off.

it seems to me, that’s fairly conclusive evidence the fuel pump is working.

Are you suggesting that it’s not pumping at full capacity?

how would a mechanical pump even do that?

does anybody have extensive Q-jet knowledge?

Would an improper float level setting and/or power valve, create this condition?

I don’t wanna rip apart my carburetor again, if that won’t help.

If you didnt do it you need to replace that float,especially if it is the black plastic looking float.Ive rebuilt them and not done it.The float either drops down and creates a flood issue or sticks at the top side and can cause fuel to not fill the bowl properly.

 

[Old60Driver]

Just a heads up. My ol girl would start, run and rev just fine. Would fall on her face when accelerating though. And that was after rebuilding my Qjet. Turns out it was my fuel pump. In the interest of time, I slapped on an external electric and she was fine.

Also, check to see if you have a check valve on the fuel filter. Fuel could be passing back to the tank.

Good luck!

 

[Ricko1966]

To test If a fuel pump is good 1st check is check the pressure 2nd check is volume lots of them will provide enough volume to idle but not enough to drive.

 

[Octane]

Just a heads up. My ol girl would start, run and rev just fine. Would fall on her face when accelerating though. And that was after rebuilding my Qjet. Turns out it was my fuel pump. In the interest of time, I slapped on an external electric and she was fine.

Also, check to see if you have a check valve on the fuel filter. Fuel could be passing back to the tank.

Good luck!

Before I rebuilt my carb I forgot it had been nearly twenty years since the fuel filter had been replaced.Then all of a sudden it was totally clogged one day and I replaced it.Found out that was partly why my truck was running a bit screwed occasionally.Then I just did a rebuild,couldnt believe how much better and stronger the thing ran.So I put 50k on the old filter from about 2002 till 2021. I now have a filter before and after the pump

 

[Octane]

To test If a fuel pump is good 1st check is check the pressure 2nd check is volume lots of them will provide enough volume to idle but not enough to drive.

On an old truck its better to replace pump,filters.Pumps are cheap.Carbs mostly can be rebuilt but many that are are not really done properly.I remember well the old days of carbs and chokes screwing up.Sometimes on cars that really werent that old.Fuel injection has been a blessing overall.

 

[Ricko1966]

I like to test the pump to verify I've found the problem,not just change it and cross my fingers that was the problem. But that was learned over many years,the customers car has to be fixed,and fixed right the first time.Its funny my old boss would tell the parts changer mechanics, okay now you have to pull all those parts that didn't fix it back off. The reason that's funny is flat rate you only get payed for billable hours if you're there all day and only do an oil change you get payed 3/10ths of an hour for your day. So when you parts on all morning and then take them back off all afternoon you kill your paycheck.

 

[Octane]

In some shops I know of,if they replace a part that didnt fix the problem the customer pays,and continues to pay for whatever else is replaced.With a hobby truck as I was referring to, it pays off in the longer run to replace a system of parts just to add some reliability back to it at times. That book labor can add a lot of money to a job that was done in half that time too.

 

[Turbo4whl]

I like to test the pump to verify I've found the problem,not just change it and cross my fingers that was the problem. But that was learned over many years,the customers car has to be fixed,and fixed right the first time.Its funny my old boss would tell the parts changer mechanics, okay now you have to pull all those parts that didn't fix it back off. The reason that's funny is flat rate you only get payed for billable hours if you're there all day and only do an oil change you get payed 3/10ths of an hour for your day. So when you parts on all morning and then take them back off all afternoon you kill your paycheck.

So one advantage of working on a fleet, you get paid as you learn.

 

[Ricko1966]

So one advantage of working on a fleet, you get paid as you learn.

Thank you I really did laugh,I m glad No one was ,here,because they'd have wondered what was wrong with me.

 

[Ricko1966]

In some shops I know of,if they replace a part that didnt fix the problem the customer pays,and continues to pay for whatever else is replaced.With a hobby truck as I was referring to, it pays off in the longer run to replace a system of parts just to add some reliability back to it at times. That book labor can add a lot of money to a job that was done in half that time too.

My experience has been customers scream bloody murder if they have to pay for things that weren't needed. Most guys on here would and most would say find a different mechanic,sounds like he doesn't know what he's doing. On your own truck as Hobbie great change all the things you want,I still don't agree with it. Seriously many O.E. parts if they test good are better quality than the aftermarket replacement parts. Example an original TBI fuel pump would go for years,it dies,you put in an aftermarket pump from advance,O'Reilly, any discount parts store.Now you're changing them every 2 years or less. When I worked at Pat's shop we wouldn't install parts store pumps on FI cars.
And the guys that beat book,spend a lot of money on tools,and they diagnose.They diagnose quickly and fix the car right the first time and change only what's necessary. Any unnecessary steps cost me money.

I'm not trying to start a war,some guys like fat girls,some guys like skinny girls. It's your life,your truck and whatever makes you feel best is what's important.