Starving

[mmt 15]

I believe my mi 16 suffers from fuel starvation.

 

goes like a bat out of h… for 1 lap and then dies completely  
 

The current setup: original tank, fuel filter, low pressure pump, squirl tank, high pressure pump, original fuel filter, rail. And return. 
 

I believe the squirl tank get too little fuel and empties. 
 

would I benefit from an extra low pressure pump ???- see drawing- forgot original fuel filter before rail. 
 

any thoughts or pointers highly appreciated.
 

thanks

 

/M 

[Thijs_Rallye 87 4 Cars]

Is this lap an oval? A surge tank normally doesn't have to be that big unless you are driving on an oval with half a tank.

[wicked 103 3 Cars]

Is your current low pressure pump in good shape? Double pump sounds a bit weird, because it only has give sufficient flow without significant pressure. 

I have a similar setup in my trackday car, but use the original GTI pump to fill the surge tank. 

Edited September 20, 2022 by wicked

[boldy205 75]

Could it be heat related? Maybe evaporation?

[petert 586]

I too use the standard GTi pump to fill a 2L surge tank, which then feeds an 044 pump. Surprising, if the GTi pump fails, the 044 will still pick up fuel, but not enough to race on.

[mmt 15]

Thanks guys

the low pressure fuel pump has less than 3 hours in service. It is a Facet posi flow pump. I surely hope it is in good shape. It sounds healthy. 
 

the high pressure pump is a Bosch - also new, also sounds healthy. 
 

it is not heat. 
 

spark plugs suggests that it run lean also Oil temp gets too high too fast. 
 

it is not oval racing. 
 

I’ll check if the in tank filter is clogged up and if I could fit a bigger straw into the original tank. Currently the straw is 6 mm I Think maybe a 10 mm Will help cure the problem? 
 

more thoughts on 2x low pressure pump? 
 

thanks again. 

[Tom Fenton 1,541]

Why not use a GTI in tank pump to feed the swirl pot?

[Spesh 31 1 Cars]

I'm not sure how much difference it would make but your returns are not the 'correct' way around, the top of the pot should be the return to the tank.  Allows air to escape back to the tank easily,

 

Are you 100% that your fuel rail connections are the correct way around too?

[petert 586]

Well spotted Spesh. It does indeed need to be like this. Except the black high arrows are pointing in the wrong direction in the diagram.

Edited September 21, 2022 by petert

[mmt 15]

Thanks a lot guys. Much appreciated. I’ll switch the lines. 
 

I am taking the original tank of the car to clean it. Inspected it last night and it is full of rubbish. It is quite amazing How much is in there. No wonder the pump could not supply enough fuel. 

[Spesh 31 1 Cars]

I dont expect that will help very much no

[wicked 103 3 Cars]

The Facet Posi-Flo Fuel Pump's self-priming capabilities provide up to 12 inches of fuel lift...

 

The Facet pump is not good at pumping against back pressure (gravity), so likely it will not provide enough flow to keep you swirl pot filled (assuming it is in the boot, couple of inches higher than the fuel tank). 

As said, I would stick to the original GTI pump in the tank.