seicento misfire?

[chip20]

Hi.I have just bought a seicento 1.1 sx 2001 Y.It had a misfire when I bought it
so I replaced the usual items.Plugs,Coil packs,Plug leads but still have the misfire.It dosent do it all the time.Seems to do it from start up.It some times last for a few seconds or you can drive 4 miles before it clears.The managment light stays on and the scanner says coil pack 2 is down but I have replaced it.Any help would be very much appreciated

 

[fingers99]

I'm tempted to ask what part of "Before you go posting your problem here, please ask yourself is it a model specific problem" you don't understand.

BWTH.

Clear the fault code by disconnecting the battery.

If the code reader suggests coil pack, first investigate the wiring to the coil pack -- is the connector dirty (clean and smear with vaseline), are the wires intact, is there a good earth to the coil pack bracket?

Next, try the old "start up in the dark with the bonnet open, look for blue flashes (HT leaks) or yellow flashes (low tension leaks) trick".

Then, try and work out which cylinder(s) is/are misfiring. Does this relate to a particular cylinder or coil pack?

In the case of a misfire which comes and goes, particularly as the engine warms up, I'd also suspect a head gasket issue -- a compression test will reveal.

If this gets you nowhere, which ECU do you have? Late and early Seis have ECUs mounted on the passenger side wing. These are ridiculously reliable. Mid period Seis had a "micro" ECU which sometimes goes faulty (often a coil pack is the cause) and gives rise to a random misfire. There's a lot on this in the Punto section (and a good search engine) Puntos were cursed with the micro ECUs: these ECUs can be repaired by specialists.

 

[chip20]

I have had a compression test done.All fine no lose of water or over heating neither.Think I will send the ECU to be repaired.
Thanks

 

[fingers99]

But save yourself a few quid first -- I think in the Punto FAQs or HowTos there's a guide to troubleshooting the ECU issues. (Also recommended reconditioners, etc.)

 

[chip20]

Thank's for your help.