Technical Car starts but then imediately stalls (codes P0353 P0352)

[K3YHL]

Hi all, hoping someone can throw some ideas up on where to look next:

My lads car is a 1.4 Punto Evo 2010 and has had an intermitent misfire for a couple of weeks and thrown the codes pointing to missfire on a couple of cylinders.

Yesterday it finally gave up the ghost and now it starts up but then immediatley stalls.

I cleared the codes and then tried again and its showing P0353 & P0352

I tested the coil pack which came back good and then swapped it with my wifes 500 1.2 which by luck has the same coil pack.

Her car ran fine using the Punto's Coil pack so that rules that out.

I then pulled the plugs which look like they were the ones originaly fitted some 70k miles ago!! anyway, changed these for some lovely new ones and still the same issue.

I then used one of the old plugs to check each HT lead to the engine block and all 4 leads have a spark so i'm guessing this rules out the Primary ECU circuit.

One thing i did notice is that when the car stalls and the ignition is still switched on, there is a loud ticking noise coming from near the throttle body at the back right of the engine bay. Not sure if this normal or not or what it is.

Anyway, thinking it may now be the Crankshaft position sensor but presume this would have thrown the code pointing to this.

If anyone has any other ideas I would much appriciate your help.

Kieran

 

[eeeno]

Codes relate to dodgy wiring circuit from the ECU to the ignition coil. However if fixing the wiring doesn't fix the issue, then the next suspect should be the ECU because running a long time with poor spark plugs damages it.

HT leads were installed correctly, none of them a little loose? They're quite tight, need to push it on the plug. I suppose HT leads don't last forever either and are very cheap to replace. Try that too.

You said about ticking noise? Well let's just say that if the cambelt has been there for a long time, it probably needs changing. It gives multiple cylinder misfire codes when something's not quite right with the belt too. Nothing wrong with the position sensors usually.

 

[K3YHL]

Codes relate to dodgy wiring circuit from the ECU to the ignition coil. However if fixing the wiring doesn't fix the issue, then the next suspect should be the ECU because running a long time with poor spark plugs damages it.

HT leads were installed correctly, none of them a little loose? They're quite tight, need to push it on the plug. I suppose HT leads don't last forever either and are very cheap to replace. Try that too.

You said about ticking noise? Well let's just say that if the cambelt has been there for a long time, it probably needs changing. It gives multiple cylinder misfire codes when something's not quite right with the belt too. Nothing wrong with the position sensors usually.

Hi thanks for the advice, will try and do some wiring checks once the rain stops and I can get some day light.
Would you happen to know if I can swap the ECU off my wife's 500 as it is the same type.
Also looking at opening the ECU up to check for signs of damage but it appears to be sealed. Is there a way to split it and reseal?
Thanks again

 

[K3YHL]

HT leads and cam belt check out fine.

 

[eeeno]

I advice strongly against swapping the ECUs from a different model. As a result you could get two malfunctioning Fiats and an angry wife.

There are companies in UK that refurbish Fiat ECUs, so I think you should try that if it indeed has a faulty ECU. Don't try to open it.

However you should check all the wiring, ECU earth wire (on the valve cover), main earth wire, ECU connectors. Good luck!