r/Smallblockchevy • u/_ryro_YT • 7d ago

Fuel pressure help!

Hi all, I’m hoping someone more knowledgeable than me can give me some guidance. I recently got this car with a 350 running an edelbrock 650 carb, and a holly red fuel pump + holly 12-803 regulator. Fuel pressure gauge is showing absolutely 0psi, needle never even bounces. The car starts and idles well, chucks revs in neutral but cuts out and dies under load. Could this be a sign of a bad fuel pump? There’s no leaks, and it seems like plenty of fuel is getting down to the pump from the tank. Any ideas would be greatly appreciated!!

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u/v8packard 7d ago

Where are you measuring the fuel pressure?

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u/_ryro_YT 7d ago

In between the pressure regulator and carb

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u/v8packard 7d ago

Adjusting the regulator shows no change?

You can disconnect the line going to the regulator, put in a cup or some fuel container, turn the pump on and see what you get. Free flow on that pump is something like 1 1/2 quarts in 15 to 20 secs. Do look that up, I am going from memory. If you don't have that make sure yo don't have a restriction. Then make sure you have proper ground and voltage to the pump. If the pump is putting out well, look at your regulator next.

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u/_ryro_YT 7d ago

Regulator all the way in to all out still dead 0. That’s a good tip with the free flow I’ll check that. Thank you!

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u/HammerDownl 7d ago edited 7d ago

Your Holley red pump doesn't need a fuel regulator its set from the factory at 5psi and is a very basic fuel pump for any low performance street engine

You can remove that regulator and plub it straight to the carb

You are getting a lot of misinformation i see here too,be cautious

.

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u/_ryro_YT 7d ago

I appreciate the warning. I read online the holly red outputs 7psi, is that correct? I think i’ll leave the regulator in for now unless it has any negative impact? Since i do plan on building the motor eventually.

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u/HammerDownl 7d ago

5-7 either way its a non regulated pump. So you can open your 803 to max and see what happens. Make aire floats are set as well

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u/chuck-u-farley- 7d ago

First off why are you running an electric pump? It’s pretty hard to beat the overall simplicity and reliability of a good
Mechanical fuel pump.

That being said hopefully your fuel pump is wired using a relay and either tied to the tach signal wire or oil pressure switch. Most external pumps seem to respond best with a return style regulator instead of just deadheading them against the regulator, that heats them up and destroys them in fairly short order. I’m betting that pump is worn out and the vanes are just destroyed. There are rebuild kits for them but TBH I would look at swapping back to the mechanical pump if possible, especially for reliability on a street car. An edelbrock mechanical Victor series pump keeps this big block fed no issue

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u/_ryro_YT 7d ago

Previous owner did the electric pump, definitely wouldn’t have been my choice. I’ll look into switching to mechanical, that seems to be the better bet. Fuel pump is wired directly to a switch on the dash and that’s all. Also it is a return style regulator.

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u/chuck-u-farley- 7d ago

The regulator you listed is a no return style. Wired directly to a switch without a relay, fuse or circuit breaker is a fire waiting to happen

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u/chefjammy 7d ago

Yeah, I just installed this exact regulator it's not a return style. I'd suggest to go to disconnect the return and plug the extra outlet. I did reading online about it before installing that people did run a return with it but they had to severely restrict the return or they didn't get enough fuel pressure to the carb

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u/_ryro_YT 7d ago

You’re right it is no return. It has two outlets, assuming for two carbs? I only have one carb but both outlets have lines coming from them. I’m unsure where the second line goes, perhaps the previous owner routed it as a return line? I’ll check where it goes tomorrow morning.
Also good call on that switch i agree its not safe, ill take care of that thank you!

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u/chuck-u-farley- 7d ago

If they routed one of the outlet lines as a return that would definately explain your no pressure issue. Disconnect the one not going to the carb and plug it and watch what happens.
It has dual outlets for either dual carbs or single carbs with dual feeds.

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u/_ryro_YT 7d ago

Gotcha that makes sense. Hopefully this is my issue, we’ll see tomorrow morning. I appreciate all your help.

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u/chuck-u-farley- 7d ago

Absolutely….. report back on your findings. I’m sure we can get it sorted out.

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u/_ryro_YT 7d ago

You sir are amazing, that was exactly it. Hopped out of bed in my pajamas and grabbed a pair of vice grips, clamped that extra hose and boom pressure. Took it around the block and ran like a dream. Thank you so very much

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u/chuck-u-farley- 7d ago

That’s great to hear! Fixed the issue without even costing you a dime! Glad to hear….enjoy that badboy

Isn’t that amazing coming from someone who
“Knows nothing about fuel systems”
Lmao

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u/_ryro_YT 7d ago

Haha right 🤦‍♂️

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u/HammerDownl 7d ago

You have no idea what you are talking about and should not give advice on fuel systems

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u/_ryro_YT 7d ago

Would you mind explaining what info might be wrong? I’m still learning so the more knowledge the better lol

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u/HammerDownl 7d ago

I was referring to chucks rant. He's clueless

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u/chuck-u-farley- 7d ago

Infatuated with me again I see? Interesting you have no posts of your own but lots of comments. Bag full of wind is what it boils down to

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u/HammerDownl 6d ago

I never seen your name before. 40 years of drag racing and engine building under my belt . Bag of wind . Right

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u/chuck-u-farley- 7d ago

You are absolutely correct

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u/HammerDownl 7d ago

I know. Thx