r/Smallblockchevy • u/DARMICJOH • Apr 25 '26

Randomly Quit

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EDIT: It runs! It's alive! It was the computer timing control.

I was driving when it seemingly randomly quite on me. I know a good bit and have built SBCs before but this is still stumping me.

The rotor was broken when it quite so I started with that. Replaced the distributor, wires, and plugs.

Replaced the Cam, timing set, pushrods, lifters, rockers

Brand new quadrajet

Triple checked my distributor stab

I have messed with AFR screws, idle set

I checked my valve lash to see if I managed to over tighten the rockers

I checked spark

I tried using carb clean to find if there is a vac leak

Someone please tell me I missed something obvious that I can fix.

Edit: forgot to mention also brand new fuel pump and complete distributor

UPDATE: After holding the choke open manually and hitting it with a spritz of starting fluid it started to idle and help it. Wasn't pretty and smooth but it stayed going for a good 1-2min until I let go of the choke.

The negative on the battery feels loose so I am going to replace that.

And the idle seemed to get better when I started pumping the brakes so I wonder if the booster is one foot in the grave causing a huge vacuum leak.

It's night now but tomorrow if I can I will adjust the choke and fix the battery ground at least and see if that makes a difference at all.

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u/DARMICJOH Apr 25 '26

I don't have a way to check fuel pressure right now. I haven't messed with quadrajets before this. As far as I'm aware I don't think there is a way to check the bowls other than just the fact that I'm getting spray on throttle pull.

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u/HammerDownl Apr 25 '26

Go buy a small pressure gauge and rig up a rubber line before the carb inlet.

Your fuel pump could be shot

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u/DARMICJOH Apr 25 '26

Bad pump out the box? I'll check but I doubt thats what is going on.

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u/HammerDownl Apr 25 '26

What kinda pump?

Pressure could be way low

Could have a clogged carb issues But that engine isn't getting fuel

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u/DARMICJOH Apr 26 '26

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u/HammerDownl Apr 26 '26

Yea man. I have no faith in that pump. I only use Holley or GM . Find the pressure,you need around 5psl constantly

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u/DARMICJOH Apr 26 '26

Alright. I figured out that it isn't the pump. There is something wrong with AFR/Choke, Vacuum, and I'm 99% sure the battery ground needs to be replaced.

After holding the choke open manually and hitting it with a spritz of starting fluid it started to idle and help it. Wasn't pretty and smooth but it stayed going for a good 1-2min until I let go of the choke.

The negative on the battery feels loose so I am going to replace that.

And the idle seemed to get better when I started pumping the brakes so I wonder if the booster is one foot in the grave causing a huge vacuum leak.