Runs out of fuel…

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
1,264
Reaction score
1,025
Location
kansas
First Name
Richard
Truck Year
1975
Truck Model
c20
Engine Size
350
Okay now that you're paying attention instead of arguing. Still 1st thing is check pressure and volume. 2nd the qjet you have is going to have to go away. All qjets are not the same, not even close, and you will not be able to make it work right on your 305. I could but it is a process. You need a qjet for (your) 305 or as close as possible by year and options. Or go with a more universal carb like a Holley. 3rd when we get the fuel and carb worked out you're going to have to learn about timing and yours is going to be rough .Do you still have your ESC distributor laying around? If so it will make your life much easier.
 
Last edited:

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
1,264
Reaction score
1,025
Location
kansas
First Name
Richard
Truck Year
1975
Truck Model
c20
Engine Size
350
Now as for your timing 305s are a 3.73 bore, and ESC 305s had compression of I believe it is 9.5-1 Ideally you are going to want about 36 degrees total and then we are going to add vacuum on top. With that compression, that bore, and no EGR we are going to have a tough time getting the optimal curve,and total without getting pre ignition. But let's climb 1 mountain at a time. Check fuel pump pressure and volume. Then we'll move to the carb. And seriously you will never get the right jets, hangers, metering rods, secondary door tensions figured out. So just count on replacing the carb.These are not simple carbs, that's why most can't make them work.After all that I'll walk you through ignition. NBD.
 

BJedi76

Full Access Member
Joined
Nov 7, 2019
Posts
146
Reaction score
16
Location
Soldotna, Alaska
First Name
B.J.
Truck Year
1986
Truck Model
GMC Sierra Classic 1500 4x4 SWB
Engine Size
305”
I do not have the old distributor.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
1,264
Reaction score
1,025
Location
kansas
First Name
Richard
Truck Year
1975
Truck Model
c20
Engine Size
350
I do not have the old distributor.

K. NBD, would have been nice to have the springs weights eccentrics and vacuum can that went with your engine, but we will work with what we've got.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
2,007
Reaction score
2,067
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
It's super confusing to read this whole thread through... but based on Rusty and Ricks comments, I'm assuming there were a whole lot of edited comments:happy175:


Like they have already told you.. first thing is to troubleshoot the engine. If it was me, and a completely unknown history engine, I'd start with the basics.

  1. Run a compression test
  2. Depending on whether compression number are within 5-10% of each other or not, run a leakdown test if not.
  3. What is your idle vacuum reading?
  4. Check fuel pressure and volume
  5. Stop spraying your air cleaner with starter fluid
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
2,007
Reaction score
2,067
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
oh, and

6. Check mechanic TDC mark for accuracy.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
1,264
Reaction score
1,025
Location
kansas
First Name
Richard
Truck Year
1975
Truck Model
c20
Engine Size
350
It's super confusing to read this whole thread through... but based on Rusty and Ricks comments, I'm assuming there were a whole lot of edited comments:happy175:
He's installed numerous fuel pumps and rebuilt a mystery qjet. He's having fuel issues and didn't want to check pressure and volume even though that's what I told him to do several times. I suspect his fuel pump lobe is worn, and he needs to get the right qjet or something less troublesome for him than trying to make a BBC qjet work on a 305. Now that he's willing to accept the fact, you have to test things, you can't just assume they are good,because when tests pass or fail we know what direction to go. Now I think this will be easy from here on in.

Like they have already told you.. first thing is to troubleshoot the engine. If it was me, and a completely unknown history engine, I'd start with the basics.

  1. Run a compression test
  2. Depending on whether compression number are within 5-10% of each other or not, run a leakdown test if not.
  3. What is your idle vacuum reading?
  4. Check fuel pressure and volume
  5. Stop spraying your air cleaner with starter fluid


He's installed numerous fuel pumps and rebuilt a mystery qjet. He's having fuel issues and didn't want to check pressure and volume even though that's what I told him to do several times. I suspect his fuel pump lobe is worn, and he needs to get the right qjet or something less troublesome for him than trying to make a BBC qjet work on a 305. Now that he's willing to accept the fact, you have to test things, you can't just assume they are good,because when tests pass or fail we know what direction to go. Now I think this will be easy from here on in.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
2,007
Reaction score
2,067
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
He's installed numerous fuel pumps and rebuilt a mystery qjet. He's having fuel issues and didn't want to check pressure and volume even though that's what I told him to do several times. I suspect his fuel pump lobe is worn, and he needs to get the right qjet or something less troublesome for him than trying to make a BBC qjet work on a 305. Now that he's willing to accept the fact, you have to test things, you can't just assume they are good,because when tests pass or fail we know what direction to go. Now I think this will be easy from here on in.

Yep... spend weeks chasing your tail or just get everything you need to troubleshoot the issue down to the ACTUAL source in a few hours of work. Sometimes we trick ourselves into thinking it will be faster to just throw a part at it, but that almost never works out well.

I just did some modification to my factory quadrajet last night in preparation for installing it on the NEW motor this week. Converted hot air choke to electric and new idle mixture needles with a 5mm hex head instead of the terrible double D head the originals had. Should make it much easier to dial in when its running right again. This afternoon will be going out to a guys house form the local squarebody group to dial in his idle mixture, idle RPM, and timing so that it drives decent again. He swapped in a new motor with an edelbrock and doesn't know how to do the fine tuning, so hopefully I can get it dialed in for him without too much trouble.
 

Octane

Full Access Member
Joined
Dec 31, 2019
Posts
1,043
Reaction score
1,555
Location
Atlanta
First Name
Eddie
Truck Year
1977
Truck Model
K10
Engine Size
350
May be it'll turn out to be a disconnected/ missing vacuum line.But I would troubleshoot that fuel pump...the 38th time is the charm? Lol. But all I see are questions and recommendations but not much action by the poster.Ricko1966 has tried real hard tho.
 
Last edited:

BJedi76

Full Access Member
Joined
Nov 7, 2019
Posts
146
Reaction score
16
Location
Soldotna, Alaska
First Name
B.J.
Truck Year
1986
Truck Model
GMC Sierra Classic 1500 4x4 SWB
Engine Size
305”
I can only work on it on the weekends.

working on vehicles is a lease violation where I live.

The manager lives 80 miles away and doesn’t come around on the weekends, so I chance it when the week is over.

Fuel pressure and volume test is next.

I just have to wait till Saturday.
 

Rusty Nail

Victim of Culture
Joined
Jan 29, 2015
Posts
7,776
Reaction score
6,438
Location
Your mom's house
First Name
Rusty
Truck Year
1977,1988
Truck Model
C20, K5
Engine Size
350, 350
A fuel pump volume test consists of attaching a hose long enough to collect gas in a container, cranking the truck over (enough to start it) and determining if you think that's enough gas or not. Pretty straightforward!

Btw, you ordered one of them .02 longer Moroso pushrods, right?
I bet that's the fix.
 

BJedi76

Full Access Member
Joined
Nov 7, 2019
Posts
146
Reaction score
16
Location
Soldotna, Alaska
First Name
B.J.
Truck Year
1986
Truck Model
GMC Sierra Classic 1500 4x4 SWB
Engine Size
305”
I’m not ordering anything until I complete all the tests, “Ricko” recommends.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
2,007
Reaction score
2,067
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
A fuel pump volume test consists of attaching a hose long enough to collect gas in a container, cranking the truck over (enough to start it) and determining if you think that's enough gas or not. Pretty straightforward!

Btw, you ordered one of them .02 longer Moroso pushrods, right?
I bet that's the fix.

I'm not really seeing how a longer fuel pump pushrod would help if the cam fuel pump lobe has been wiped out. Generally when the lobe is wiped it only wipes the tall side, which makes it almost round. If you have no eccentricity to the lobe, it won't pump even if the pushrod is making contact.
 

Rusty Nail

Victim of Culture
Joined
Jan 29, 2015
Posts
7,776
Reaction score
6,438
Location
Your mom's house
First Name
Rusty
Truck Year
1977,1988
Truck Model
C20, K5
Engine Size
350, 350
Well, good luck with all that.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
1,264
Reaction score
1,025
Location
kansas
First Name
Richard
Truck Year
1975
Truck Model
c20
Engine Size
350
Volume cranking with starter, disconnect power to distributor. Crank 30 seconds you should have approximately 3/4 cup of fuel. For your pressure test I forgot you have 3 line pump.1 of those is a bypass return. So your gauge is going to jump up but not hold so watch the gauge while you are cranking
 

Latest posts

Forum statistics

Threads
33,669
Posts
697,411
Members
21,230
Latest member
76 Newbie
Top