What Are Fuel Surge Symptoms ?

[useless]

The dreaded hesitation seems to have come back to haunt me.It got worse by the end of today as the fuel level went close to empty.Ironically tonight on my way to the shops with the family it was very prominent.I filled up at the petrol station and the problem stopped immediately. Is this fuel surge? Is the standard fuel pot just too small to cater for fuel delivery to bigger injectors?

Can I just use a second inline pump such as bosch 044 to solve the problem?

Sorry I just realised I did not describe the symptoms well enough. The car intermittently seems to stumble off idle and part throttle when taking off from a standstill. Tanks been cleaned,pumps changed,lead changed,throttle body changed,plugs too..

[JP300]

Spot on description ... never push the car when you have less that 1/4 tank showing on the gauge.

Why: (my theory)

The more power that a car can put to the ground the more g-forces the more splash around in the tank as it is nearing empty. This causes the pump to suck up air --> loose fuel pressure --> little or no fuel going through injectors.

Fix = external properly setup surge tank in a safe location

Problem = External surge tanks can be dangerous in situations that a car gets hit in that corner/location. This is particulary worse in situations that the Surge tank sits over an exhaust pipe !!

My 2cents worth ...

[useless]

How about an inline pump on its own?

[JP300]

If the intank pump sucks in air then the inline pump still gets no fuel !

[RAP1D]

Yes, a surge tank the only way to avoid this.

Using an 044 inline of the stock pump wont resolve the surging issues that the stock pump is having... basically the tank was designed to have a pick up that needed to support 300plus kws.

Yours does sound very serious though. I can drive mine on a very low level and its fine on normal tame driving... maybe one of the fuel lines is kinked or something, reducing flow

[JP300]

My car is also fine at very low fuel levels. I drove mine to empty once and did not have any problems until the engine cut out all together ...

(... I was driving out of the city going home from being at Darling Harbour at a car show. The distance to empty went to zero. I was telling the guys that I have driven the car for 20 - 30 ks without running out of fuel on zero. As soon as I finished the sentence it cut out ... I had enough momentum and got the lights to roll down the hill into a servo !! ... )

[useless]

This thing is temperamental.Most of the time it is fine.I am leanning towards fuel surge or something wrong with the injectors.?Will see tommorow if the car behaves with the full tank. If so ..I will be installing a temporary fuel gauge in the car untill I see if I lose pressure.

[JP300]

Where abouts are you located ?

If the car has problems with a full tank then it is not a surge issue ... as Rapid said, it could be line, injectors, pump etc ...

[useless]

I live in Sydney JP300. I will see tommorow how it behaves. The problem seems to occur under initial load from stopping .Light load gives a general hesitation and a hard throttle sometimes backfires then the car goes very well..all intermittently. If the car plays up tommorow the injectors will be changed to el;iminate this from my list.

It is funny how the problem dissappeared after stopping at the garage and filling the tank..

The only item not changed are the injectors..

[2fardown]

I would temporarily fit a fuel pressure gauge in the cabin. When the problem is occurring, take note of the pressure. This will tell you a fair bit about what's going on.