High Fuel Pressure and Acceleration Bog

[Tynan918]

My engine bogs when I accelerate from a take off from a complete stop like at a stop light or stop sign...

Once I mashed the gas and it stalled, but started right back up.

Checked fuel pressure and its 9psi...Edelbrock carbs fuel psi are rated 6.5 max.

Could the way too high fuel pressure cause the bog at acceleration at take off ?

 

[SSMonteMan]

Depends on why it's bogging. Is it due to too much fuel or not enough. If you're mashing the gas and it boggs down but then after a moment comes back and takes off, that would be accelerator pump not working, causing a lean condition that is resolved when the vacuum comes back and pulls fuel through the main jets.

If it stalls and dies, could be too much fuel, which may be due to your excessive fuel pressure. Do you have a Regulator? Can you adjust it down? 6-7 PSI should be fine.

Do you have a wide band ARF gauge? They're kinda expensive but very valuable when tuning in a carb.

 

[SSMonteMan]

Also, is this a new issue? Or has it been like this since you put the carb on?

 

[Tynan918]

If you're mashing the gas and it boggs down but then after a moment comes back and takes off, that would be accelerator pump not working, causing a lean condition that is resolved when the vacuum comes back and pulls fuel through the main jets.

If it stalls and dies, could be too much fuel, which may be due to your excessive fuel pressure.

At take off from a complete stop or a rolling start, it bogs/hesitates/stumbles to accelerate properly... and as long as I'm lightly holding the gas pedal down, things smooth out once it jumps in 2nd gear, but once I come to another stop and accelerate through first gear, the bog/hesitation/stumble happens again. I mashed on the gas once from a complete stop and it stalled.

I reset initial and total timing from 8°BTDC and 36° total to 6° BTDC and and 32° total...bog/hesitation/stumble has bettered.

...and swapped my vacuum hoses around and the acceleration... bog/hesitation/stumble has bettered.

I didn't have this problem until my radiator fan cut open my upper radiator hose shooting rusty water on everything of the engine and my air filter was not attached exposing my open carburetor (haven't cleaned it yet, water killed my last battery and alternator), and swapped my electric fuel pump for a mechanical fuel pump.

 

[Tynan918]

Do you have a wide band ARF gauge? They're kinda expensive but very valuable when tuning in a carb.

My uncle has one in his Challenger but he said it was a b**** trying to install, but never showed or told me how he installed it... are you referring to a gauge that I can mount on my dash?

 

[Tynan918]

If it stalls and dies, could be too much fuel, which may be due to your excessive fuel pressure. Do you have a Regulator? Can you adjust it down? 6-7 PSI should be fine.

I don't have a inline fuel pressure regulator, but I'm buying one come Friday...maybe the Holley brand, I see good reviews on those, and the Edelbrock brand I can't find...

 

[SSMonteMan]

Yeah, AFR gauge is a Air:Fuel Ratio gauge. It'll tell you if you're running rich or lean. It's not too hard to install, but with your wiring as it is, I would avoid adding to it as much as possible. They're also a couple hundred dollars.

I assume you're running an electric fuel pump, from your other posts that illude to that, and the engine you have most likely not having the hole for a mechanical pump. You should definitely have an adjustable regulator with a return line in that setup.

 

[Tynan918]

I assume you're running an electric fuel pump, from your other posts that illude to that, and the engine you have most likely not having the hole for a mechanical pump.

I now have a mechanical fuel pump, I plan on buying a regulator this Friday...probably the Holly branded one.

 

[Tynan918]

Yeah, AFR gauge is a Air:Fuel Ratio gauge. It'll tell you if you're running rich or lean. It's not too hard to install, but with your wiring as it is, I would avoid adding to it as much as possible. They're also a couple hundred dollars.

I've changed and cleaned up a lot of that wiring under the hood...I no longer have the distribution box, the alternator has the correct gauge running from the battery and grounded, and a new two wire resistor plug, the starter is wired up correctly, and I got rid of the electrical fuel pump.

 

[SSMonteMan]

9 psi is really high for a mechanical pump, what pump did you get?

That china junk gauge isn't what you want. If you want an AFR gauge you'll need one with a wide band O2 sensor, not one that plugs into a computer. This is what I have: https://www.summitracing.com/parts/avm-30-0300