Technical Seicento stutters when tank is half full

[Jelle05]

Hello everyone,

I’m new on the forum and I daily a 2001 fiat seicento 1.1 mpi sporting, because my megane 3 RS is awful as a daily driver. But unfortunately the car has had some problems the last weeks. One thing that I can’t find out is the stuttering.
When the fuel tank is beneath half full, the car begins to stutter and loses all the power. The emptier the tank is, the worse it gets. And it’s not driveable anymore. When the power goes away, I just have to restart the car and it works until the power goes away randomly.

I’ve cleaned the fuel tank and ‘filter’ (the little filter in the fuel pump) because those were a tad dirty. I checked the spark plugs and those work fine and look good.

What do you guys think I should check or replace? Or is there a forum with this problem?

My mechanic friend told me the fuel pump housing could be cracked and it suck dirty air in from there, but I want to know for sure before I go and buy a new pump and housing.

 

[FiatMatt94]

Maybe there's some crud in the pipes or the throttle body, whenever I fill up with fuel I put in redex fuel system cleaner in the tank which cleans the entire system, pipes, throttle body etc & I can confirm this stuff works as I had my throttle body off last week to change my rocker cover gasket, the inside of the throttle body was spotless & looked brand new, another thought is which type of petrol are you running it on as in the UK we have both E10 petrol & E5 petrol. The E10 is 10% ethanol & E5 is 5% ethanol, the Seicento's don't like the E10 fuel but a lot of people will put the E10 in as it's cheaper than the E5 but Seicento's don't run very well on E10 as I found out when I purchased my car 7 months ago so I switched to E5 & it ran perfectly.

 

[valeter]

check the fuel tank isnt leaking have any signs of wet fuel around the tank seals and also the fuel filler cap seals properly sometimes you can end up getting an air vac leak which can affect things as when the tank is half full thats now half a tank of air thats getting sucked in from somehwere and then air into the fuel lines combined with air in the fuel making the ecu go WTF ,,,its worth a look at least