205 Rallye 1.6 On Twin 40's Misfiring When Driven Hard

[Tandoh 17]

Right ok well my rallye has a vtr bottom end with 1.4 head n piper 285 cam running twin 40 carbs.

Well what seems to happen is when you drive the car hard, it starts misfiring. Occasionally if you turn the ignition off then on again it's back to normal. Usually if it happens when you have only 1/4 tank of fuel then you have to leave it overnight and hen it will be alright. It's got an electric fuel pump n pressure regulator. Had the fuel pressure tested on the rolling road n it was around 3 n they said it was perfect.

 

This is really starting to irritate me

cheers everyone

luke

[swordfish210 20]

Fuel surge, the standard tank has no baffles in and as such under hard right hand bends the fuel sloshes away from the pick-up pipe so it's just sucking up air.

[Tandoh 17]

Any idea how I can sort out the problem? Would I need a different tank?

[swordfish210 20]

Well i supose it would be possible to remove the pick up pipe and stuff the tank full of fuel cubes. I doubt it would work very well though. The ideal solution would be to have an alloy tank made with a baffle system built in.

[Tandoh 17]

What about getting a fuel swirl pot? Cheers

[swordfish210 20]

What about getting a fuel swirl pot? Cheers

 

Yeah it's certanly an option. I have a 750ml swirl pot but i still get a pressre loss around Combe (and Llandow) with anything less than 1/2 tank. You could fit a larger swirl pot (1.5L or something) and have a high flow fuel pump feeding it like a Facet Red Top which may help even more.

[backroadpug 12]

tell me bout it noting worse than hitting a tight right hand corner and the car loosin all power then boom of she goes again

[vickiw106 1]

as far as I am aware when running carbs you should get fuel surge problems as they have a reservoir that holds fuels

 

if your fuel does surge in the fuel tank for a second or two the engine will use the fuel in the carb reservoir and it shouldn’t misfire,

 

i had a very similar problem and found it was the carbs tightened to much to the manifold, this was causing to much vibration on the carb side and aerating (think that’s how you spell it) the fuel to much hence the misfire,

 

Just another thing to consider

[205Rallee 59]

I have no problem with twin 40's, standard fuel pump , tank and sticky tyres on my TU24. It will go around any right or lefthanders with the fuel warning light on and no fuel starvation.....

[MrG 3]

same here with my 1.9, as vicki says check the carbs are not too tight on the manifold as this allows the fuel to froth due to vibrations and that doesn't help at all. You should be able to just about move the carbs up and down a bit on their manifold.