Symptoms of fuel surge ,what are they?

**Stav** · 28-06-2007, 08:24 PM

Guys I am fighting again to eliminate my misfire/hesitation off the mark and at light throttle. The problem is intermittent. My fuel got low today and the problem was there alot.As soon as I filled up to full of fuel the problem immediately dissappeared The problem has occured with standard pump and 500 hp walbro pump..

Is this typical of fuel surge? What are the symptoms of fuel surge? Will I need a tank or just a second inline pump?

stiddy · 28-06-2007, 09:40 PM

Quote:

Originally Posted by Stav

Guys I am fighting again to eliminate my misfire/hesitation off the mark and at light throttle. The problem is intermittent. My fuel got low today and the problem was there alot.As soon as I filled up to full of fuel the problem immediately dissappeared The problem has occured with standard pump and 500 hp walbro pump..
Is this typical of fuel surge?

YES, the fuel pump uses its complete base area as an inlet to pick up fuel, and it will do this efficiently whilst the complete area is covered with fuel. If the fuel level is low enough to allow part of the inlet into fresh air, the pump will draw air & not fuel.

Quote:

Originally Posted by Stav

What are the symptoms of fuel surge? Will I need a tank or just a second inline pump?

Symptoms?
Like you said misfire, hesitation, and it will run rough, lack power, bad fuel economy, and pretty much just run weak.
2 pumps is over kill, the walbro is plenty, make sure your fuel filter isnt blocked, your fuel pick up is low enough and not blocked...... its not a tuning issue is it?

Turbot · 28-06-2007, 10:24 PM

You might want to also remove your intank pump and check the fuel hoses on the pump for cracks / splits, pretty much the only real submersible fuel hose is Gates submerible fuel line bout $30-40 a foot.

**Stav** · 28-06-2007, 10:38 PM

I am thinking an injector or fuel surge . Tommorow will tell for sure.A good drive with a pretty full tank should still see no problems..otherwise I will be looking at other injectors.The power once the stumble goes is awesome every time.It goes hard.I really want to fix this problem to run the car.
On some occasions it happens when half is full.I think the walbro may be emptying the swirlpot too quickly when it gets to that level ? When full the swirlpot would be overflowing with fuel. Maybe I will have to drill out the side walls of the pot to allow a greater amount of fuel in at lower levels?i dont know ..it is annoying though.

**Stav** · 30-06-2007, 01:55 AM

Today I got home and installed my autometer fuel pressure gauge. I mounted it externally for a temporary time like fully sick gauges.I went for a drive and the problem reappeared.The fuel pressure was perfect and pretty steady when the problem occurred .It is not a fuel surge issue .Pressure is perfect. I am now thinking a slight air leak somewhere on the intake side or an injector not doing its job right.