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Discussion Starter #1 (Edited)
I have a magnafuel prostar 500 fuel pump with a quick fuel regulator and for some reason my fuel pressure creeps up and will actually peg the guage out while idleing. this is the second regulator i have had on here that does this. If i remember correctly I have the fuel pressure coming from the pump set to 27 lbs and the drops to 6 on the quick fuel regulator. 10an line to the front and the bypass off of the pump like magnafuel shows it. What is causing this? do I need to lower the pump pressure more? or get a different regulator?
 

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hope u dont have a liquid filled gage. even if u dont, try a diffrent gage. perhaps your regulator is a strong enough unit to handle it, but maybe inside of regulator u have a defective seal or something like that. but seeing as its the second reg. id bet it might just be the gage
 

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Get an after pump filter and adapter fittings from MagnaFuel. The mount the filter and regulator together.

MagnaFuel regulators are very sensitive to even the smallest foreign bodies in the fuel. When we put the after pump filter on our pressure creep problem we worked on for 16 months went away.
 

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if it pegs the gauge(and its accurate) youll have fuel pouring out of the vents. 27psi is too much pressure at the inlet for a quick fuel regulator if its the holley style. need to dial it back to 16-18psi inlet pressure.
 

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I have a bypass at the fuel log. Use a .020 n20 jet and run a -4 line back to the cell.
Magnafuel shows a simliar deal on their website so it must be pretty common.
 

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I'd say too much pump pressure.....drop it back to around 15 and see what it does.
 

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What size return line. May be a combination of things. I don't think you need more than 22/23psi primary pressure and I would go up on pressure to carb like 7-8psi and see if that will hold. 27/6psi is a lot to ask from a general purpose reg. I like the Aeromotive regulators the best and Magnafuel has good stuff too. I have a BG bypass reg setup on two of my slower NA cars and it works great, rock solid press but you have to run a #10 return line all the way back to tank from carb. These cars are streetable so did this mainly to help pump run for extended periods. Hope this helps.
 

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Discussion Starter #9
Its definetly not the guage. if I don't catch it in time it will actually flood the the motor out and start running like shit. I have the magnafuel pump with the built in filter. Where my pump is located I really don't have room to add another filter between the pumps built in filter and my fuel cell. Ill try droping the pump pressure down to 22 or 23. But how much will that affect the amount of fuel im getting to the front? I use one fuel system for motor and nitrous with a magnafuel log in the front that feeds the quick fuel reg. for my motor and a holley regulator for my nitrous fogger. I have noticed once you get the car running for a minute and get driveing and useing some fuel and not just idleing the pressure creeping problem will go away.
 

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well if u have the big two port regulator(which is prob what u need and u have same pump i do and i went with the big two port reg and no probs) then i think something wrong with regulator...if u dont have the big two port magnafuel reg, get one. they are about 220 bucks
 

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How do you turn the fuel pressure down coming off the pump ? I'm having a issue with the car running smooth at idle. If I'm at a stop light, the car seems to leave the line kinda choppy, But once I get into the gas it runs good. I'v had the engine dyno'd with the carb thats on the car now, so I know it's tuned correctly to my set-up. Thats why I seem to think its the fuel pump.
 

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are you watching the fuel pressure when this issue occurs? could be power valve, timing, and also intake manifold runner length or the way its split. my car will chop just off idle till about 2K, then smooth as a stock motor. pull the plugs from idle, outer 4 clean. pull them after a wide open run and all the plugs are near the same. i dont know if velocity is the right term?
 
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