Technical Fiat Punto 1.2 2004 missfiring

[FiatSwede]

Hi I'm new here and have a problem with mu friends Fiat Punto.
Cylinder 3 missfires.
I have changed the coil.
I have changed the ECU.

When i look with the strobelamp to check if the spark comes i notice that cylinder 1 and 3 flashes "slower" than 2 and 4 who is flashing more often.
Sometimes cyl 3 is "dark" for a short while.

As i see it this is an engine that ignites every time the piston is on top, even if the exhaustvalve is open.
But in that case why does it miss cylinder 3 if the pulse comes from the crankcase and do not take the camshaft position in considiration when sending the sparksignal.


Does anyone have an idea or had similar fault?
Or have i missunderstud how the ignition works on this car.

Best regards Andreas from Sweden

 

[flisko]

spark plugs ht leads coils or engine ecu
what engine?

 

[torgut9]

Hi,
got same situation here.
Find out if ignition leads are bad and spark jumps to the cylinder head causing misfire.
I had mint looking leads with good resistance measures but still spark found its way to cylinder head making random misfires.
I covered each lead with rubber tube from bicycle tire and it cures the misfire problem.
New set of leads installed now. Misfires came back few days after new leads ... still figuring out how to insulate lead boots properly in spark holes so they wont leak spark to cylinfder head

Other reason for same kind of misfires in Punto in generaly is leaking head gasket - got one with my earlier Punto. This usually cause the loose of coolant.

 

[FiatSwede]

Hi guys.
The Punto has been put aside for a while in favour for other projects.
But now i plan to do a new attempt.

The engine is a 1.2 16v 59kw/80hp 2004.

Coil changed.
EVY changed.

I will start it while it's dark to se ut there is a firework somwhere.
I will also do a comp test just go be shure.

One question remains regarding from where the ECU gets the information wich cylinder is going to ignite.
Would be glad if somone had that information and make an wiring drawing.

Regards from Sweden

 

[Scudmonkey]

Hi guys.
The Punto has been put aside for a while in favour for other projects.
But now i plan to do a new attempt.

The engine is a 1.2 16v 59kw/80hp 2004.

Coil changed.
EVY changed.

I will start it while it's dark to se ut there is a firework somwhere.
I will also do a comp test just go be shure.

One question remains regarding from where the ECU gets the information wich cylinder is going to ignite.
Would be glad if somone had that information and make an wiring drawing.

Regards from Sweden

Crankshaft sensor...some have camshaft sensor too