Holley carb too much fuel pressure. Dec 26, 2011 · IMO, Put the new Holley Brand needles and seats in, not cheap-O's. 8. Nov 5, 2022 · Learn about Holley carburetors troubleshooting where everything from basic troubleshooting tips to advanced diagnostics and tuning procedures are discussed in great detail. Also check your float level on the carb. A Holley carburetor is vital for your engine’s performance. After my car sits for a few days I'll go to start it and it will fire up and If your fuel pressure is too low, you run the risk of running the fuel bowls dry. Does anyone know what would cause the one booster to dump too much fuel? Would this be causing the surging, assuming everything else is in order? Any help would be greatly appreciated. You can see the fuel literally flow into the engine, and the engine will stop after about 20 seconds cause of over fueling. Check for sufficient fuel pressure. It's also possible that your float needle is damaged and not sealing allowing too much fuel into the bowl. manufacturer specifications dictate 5 psi to the carb in order for p I'm hoping that the excessive fuel coming out of the one booster is the issue with the surging (maybe not the slight hesitation). This video will help explain fuel pressure regulators that were designed for use with a carburetor. Most electric fuel pumps (especially designed for fuel Sep 5, 2019 · When choosing a fuel pressure regulator for your ride, you need to take into consideration several factors. Jun 9, 2021 · One of the most important factors of tuning a carburetor – is having the proper fuel pressure to feed your carb. Regular maintenance and adjustment are key to optimal performance. They will also flood if excess pressure is applied. From rough idling to poor acceleration, a faulty carburetor can cause many headaches. I'm pretty sure I did not indent or damage the regulator's housing either. Way to high for me. Last edited by 69cam; 04-20-2015, 11: Mar 20, 2014 · Holley carb fuel pressure? Pontiac - RacePY Online Forums - Bringing the Pontiac Hobby Together > General Classic PONTIAC TECH > Pontiac - Race > Holley carb fuel pressure? Nov 2, 2010 · Holleys will tolerate a maximum of 6 1/2 lbs of fuel pressure before the pressure overpowers the needle and seat and blows raw fuel into the intake manifold, so get the pressure under control, like 6 psi. Historically, a 1963 Pontiac 421 Super Duty with two 650 CFM AFB carburetors was equipped with a 12 PSI mechanical fuel pump. 5 PSI. Jul 10, 2015 · Thanks, Holley says their carbs can handle up to 8, I'm not getting much choices, The Carter super street pump is $167, lot of coin for a mech pump. If the pressure is too high, it can force too much fuel into the engine. Oct 31, 2024 · For those using a Holley carburetor or fuel injection system, having the correct pressure setting is essential for optimal performance. A stock AC Delco mechanical fuel pump is designed to put out 5-1/2 to 6 psi. I'm running a 650 Holley double pumper and it seems to run rich at wide open throttle. Any suggestions would be greatly appreciated, car should be able to run up to 6800rpm but I was running out of fuel by 5000rpm. This is what happens when a piece of dirt gets stuck in the needle/seat assembly. Again, you would see fuel dripping from the main boosters. I checked: Jan 5, 2014 · I have a Holley 750 that was showing 5. Check the Floats, and make sure they are not half full of fuel, and set properly! Also, if the stock pump is putting out that kind of fuel pressure 10psi, you need a fuel pressure regulator, and dail it down to 6psi max!!. Dec 28, 2016 · Mechanical fuel pumps can range from 5 psi to 12 psi. Understanding the common problems and their fixes can save time and money. Just where I want it. Explaining the importance of Fuel Pressure Apr 24, 2011 · The fuel pump says it puts out 5. FWIW those little Holley fp regulators are preset at that pressure. I'm not sure if I should start tuning on the carb or get a fuel pressure regulator and make sure the pressure isn't too high. 5lbs A stock holley needle/seat assembly will be forced open if you run the pressure high. Thanks guys and gals. Nov 26, 2017 · If you run that fuel pimp without one, or set incorrectly the pressure will over power the float needle and flood the engine. 5psi at the fuel log on the carb. Can only keep it running by increasing the idle speed. Aug 15, 2015 · What fuel pump did you install on your car? A stock mechanical fuel pump for a carburated engine should put out only 6 psi. Dec 30, 2024 · Holley 350 & 500 cfm carburetors will work with a slightly higher fuel pressure. Too small of an accelerator pump in carb(s). 0 psi. The way to go is the strip with reg but I really didn't want to go that route. Sep 19, 2011 · 6. Mar 27, 2024 · Apparently, newer mechanical pumps put out far too much pressure for these carbs, which seem happiest around 5-6psiplumbed in Holley regulators on both and no more issues. Either increase the pump size or the nozzle size or both. You might have to take carb off and check secondary throttle blades,stop might be open too much from factory The importance of knowing too much fuel pressure to carb symptoms can be summed up in a single line. That is a descent range and there is no adjustment that I know of on the pump. That can cause fouled spark plugs, among other issues. It controls the air-fuel mixture. They will take 4 - 6lbs of fuel pressure before the needle and seat will not hold the pressure. Get a gauge and check the pressure. do this pumps make too much pressure for the holley carbs? what pressure do this carbs like? edelbrock performer RPM goodies on both engines. If that happens fuel will pour out the vent tube and into the carb venturi's. Unfortunately, many folks are running fuel pumps (mechanical or electric) that push too much pressure for street use, causing a multitude of headaches, like… Overfilling the fuel bowl Flooding Rich running Hard starting Poor gas mileage Damage the needle/seat Aug 25, 2023 · Two pressure gauges in to rule out a faulty gauge & I'm now on my second fuel pressure regulator and the pressure ends up being way too high, I've seen over 100 psi and as low as 80 psi with either fuel pressure regulator, blue filter cap on & off. There were slight flooding problems at idle with the Pontiac Super Duty cars. The regulator is a critical piece and should to be matched to the type of fuel delivery system and the fuel pump that you are using or plan to use. This guide will help you identify and Apr 26, 2011 · I'm having issues with two different cars, both have the same 350 SBC with holley 1850 carbs, both have the stock chevy no return fuel pump. 7-8. If you are running a high performance mechanical fuel pump such as a holley 12-289-35, it will put out almost 16 psi which will blow the needle valve open so yes you will need to run a regulator on this type of pump. 5 psi for this type of carb, but it seems to me that since it is a Holley pump, it is probably calibrated in the right range (gauge reads a steady 8psi). Jun 25, 2013 · fuel volume is the important part. Jul 28, 2015 · To make the metering and atomization functions of a carb work as intended fuel pressure, flow, slosh, and foaming management are all critical. You need a good amount of airflow to cause a negative pressure change, to get the mains to start flowing. Shown here are the main jet extensions used to compensate for fuelbowl surge during high-g operation. Sep 8, 2021 · Mains won't start flowing till about 2000 RPM, give or take a little. My problem is, when I go out in the morning while the engine is cold, turn on the key to get the fuel pump running, my fuel pressure is 7 PSI. It is the cause of poor engine performance, and lead to fire hazard. Sep 11, 2025 · Holley carburetor troubleshooting primarily involves checking for fuel leaks and ensuring the air/fuel mixture is correct. Started up; getting too much fuel through the discharge nozzles and the booster venturis. Nothing works. 0psi a common item that is often overlooked when having holley problems is the fuel pressure. Oct 13, 2012 · I've been battling this issue for way too long now and am seeking some help. Your regulator is adjustable. At idle, mains will not flow, unless something seriously wrong with carb. Anyway, the regulator is on order and I am going to adjust the max pressure to 7psi. They could have used a pressure regulator. Running 8AN feed from the tank, sumped, all the way to the carb and a 6AN return line at the regulator. When it malfunctions, your vehicle can suffer. It almost bogs like it's dumping in to much fuel. Valhegen Jun 19, 2025 · Knowing how to troubleshoot these problems is key. I start the engine and fuel pressure goes to 10. I used to use a regulator with stock pumps just to mellow the pulses (mechanical pump)You need to have a good line from tank,7/16 is better than 3/8. This prevents flooding from too much pressure on the needle seat assembly. May 9, 2010 · I use an adjustable type fuel pressure regulator located between the stock fuel pump and the Stromberg carbs and set it at 2 1/2 lbs. Mar 19, 2012 · There is some info on the Holley website that suggests a max fuel pressure of 7. In this guide, we'll walk you through how to adjust Holley fuel pressure regulator for improved engine efficiency and power. Feb 12, 2016 · I've got a Holley 750 double pumper carb with a 110 GPH "Blue" fuel pump and a 12-803BP regulator. The design of the fuel system from the tank to the carb’s jets dictates successful operation. epx0 k7d lyj7f ny05 sa ku vuto 5dcl wizexj 2rec