Fuel Issues

[buterbaughb1]

I've been having fuel pressure issues all year and I'm fairly new to this, so I'm stumped. The fuel pressure has been real erratic, jumping all around at speed. It would then run consistently at 9-10 lbs., so i put a regulator on it to keep it consistent at 7, and it still would flutter and cut out when at the end of the straights or when i pick the throttle back up in the turns. I've got a brand new carburetor, new regulator, and a brand new fuel pump. Any ideas? I have a -10AN line to the pump and a 3/8" line to the carb.

[usafracer]

What fuel are you running? What kind of filter do you run?

What kind of pump is it? What style of pump is it?

[82Motorsports]

That 3/8 line won't cut it. Should be at least a 08an I believe. It's too restrictive as you have it now and you're running out of fuel in the carb.

[Egoracing]

I agree, a 3/8 is a -6 line and you need a -8 which would be a 1/2 inch.

[buterbaughb1]

What fuel are you running? What kind of filter do you run?

What kind of pump is it? What style of pump is it?

I run 113 VP, not sure on the part number on the fuel filter but its a WIX filter and is 8" long, its close to the tank. Its a Holley Keith Dorton Series High Perf. Pump, mechanical.

Thanks for the tips. Ill make an -8AN line this week.

[gadirtracer]

Sucking air somewhere between cell and pump?
Does the engine miss or just inconsistant fuel pressure @ the gauge?(Bad gauge?)

[Egoracing]

Is your filter the round one that you unscrew the end to open it? If so make sure that the open end of teh element is to the front, then the spring and then you cap it and the incoming fuel hits the closed end of the filter element. If it is the other way the fuel pump will pull the filter forward and shut off the fuel supply.

[buterbaughb1]

I pulled the filter apart and it was in the correct direction. The motor will run like hell on the straights but miss at the top end, and if i pitch it hard into the turn and hold it wide open, it stutters and carries on till it gets back around to the straight. I thought it might be a bad gauge, its a good auto meter but the fact the motor is still stuttering doesn't prove a bad gauge, i could be wrong. I will get a new, small inline gauge and try that. I thought it might be sucking air somewhere, but wouldn't that lean the motor out and cause it to over heat? its been running 170 all season. I have run it on jack stands and gone over the entire system ,there's no apparent leaks. How would i detect if it was sucking air somewhere? Someone mentioned that i run foam in the cell and it could be breaking down and clogging the system. The foam is only a year old, and there's no black flakes on the filter. I appreciate you fellas input, because I'm stumped.

[bushracing67]

-6 or 3/8 from the pump to carb should be fine with a 2bbl, it will not hurt to switch to 1/2" line but i doubt that is your issue, as long as you checked the filter and pick up in the cell next i would look at your fuel cell vent and make sure the check ball isn't hanging up, from there look at how many 90 degree fittings/bends you have in the system front to back, use as many straight or 45 fittings as possible... i would recommend trying another pump just to eliminate that as a variable as well

[Dirtrunner35]

I ran 3/8 line from pump to carb for 10 years with no problems. Maybe your float is to low ?? Like bushracing67 said, check the pick up in the cell.

[4bangerhotrod]

make sure the foam in your cell is not getting close to the pick up tube. ive had the same problem before and the foam was moving around a little and the pickup tube was trying to suck the foam up an blocking the fuel. make sure you cut a big square in the foam where the pickup goes through or just take out the foam all together.

[buterbaughb1]

Thanks guys. I didnt think of the foam blocking the pickup, il pull it all out and make sure it does block anything.

[bushracing67]

a simple fix is to put a wiffle ball on the end of the pick up, it acts as a cage keeping the foam away from the pick up

[stock car driver]

I've been having fuel pressure issues all year and I'm fairly new to this, so I'm stumped. The fuel pressure has been real erratic, jumping all around at speed. It would then run consistently at 9-10 lbs., so i put a regulator on it to keep it consistent at 7, and it still would flutter and cut out when at the end of the straights or when i pick the throttle back up in the turns. I've got a brand new carburetor, new regulator, and a brand new fuel pump. Any ideas? I have a -10AN line to the pump and a 3/8" line to the carb.

Isnt 113 oxygenated? I know I have too much compression to run that stuff..

[Dirtrace54]

If its the green VP 113 then yes it is oxygenated, but most prefer it on a 2 barrel. Ive ran a 3/8 line on 2 barrels and 4 barrels to 7500 with no problem on gas. Id say the sucking air description fits this problem the best. Do you have a warning light with the fuel pressure gauge? Ive never had a problem with fuel pressure unless it dropped below the warning area where the light comes on. Make sure the carb is set up right also, seen where oxygenated fuel requires wetter jetting with jets 2 to 4 points richer than regular fuel because the oxygen in the fuel requires less air in the mixture.

[buterbaughb1]

its not oxygenated. Ive been buying fuel at the track and i havent gotten around to buying a drum yet, multiple guys are running the same fuel without issue. Its a 9.5:1 motor so I dont think that compression would be an issue but i could be wrong. I do have a warning light, and it comes on and it bounces around like crazy, ive never seen a gauge bounce around so much but the motor is sputtering in sync with the gauge so i think the gauge is OK.