Technical Punto 2004 1.2 8V missfire/failure

[rkwheeldon]

Missfire started a week ago with intermittent engine warning light. Took it to my mechanic who read error codes which indicated missfire on No. 4 cylinder. Replaced all plugs and new leads. Missfire returned and now continuous with engine management light on all the time. Also mpg reading stopped if thats a clue. Tried to start yesterday and it wouldnt. Any help much appreciated.

 

[varesecrazy]

Missfire started a week ago with intermittent engine warning light. Took it to my mechanic who read error codes which indicated missfire on No. 4 cylinder. Replaced all plugs and new leads. Missfire returned and now continuous with engine management light on all the time. Also mpg reading stopped if thats a clue. Tried to start yesterday and it wouldnt. Any help much appreciated.

Basics :

Has the coolant level dropped?

What does the oil look like on the dipstick?

Yellow warning light..?

 

[rkwheeldon]

Basics :

Has the coolant level dropped?

What does the oil look like on the dipstick?

No. Coolant level is fine. Oil is nice and clean too ( changed one month ago).

 

[rkwheeldon]

Yellow warning light = engine management light.

 

[varesecrazy]

That's good news.. As should rule out head gasket

So..
The garage visit restored service for a little while.. (so something they did was of benefit..)

The Yellow light is generally just a check on emissions (a sensor in the exhaust)
A misfire means it doesn't burn all the fuel.. And the sensor warns you of that


Common 'ish to have a Coil Pack fail on the 8 valve FIRE motors

There are 2, serving 2 cylinders each

When previous light was on, did it tick over smoothly.. Or lumpy?

 

[rkwheeldon]

Intermittent smooth/lumpy. The new leads and plugs hasnt made a noticable difference. My guess is coils next but for the car not to start at all? I would have expected start but missing so no start has me wondering. Also does the lack of mpg info indicate a problem with the ECU?

 

[Greasytrucker]

Could it be that the coil pack that serves 3 & 4 has failed completely now hence it won’t start on just 2 cylinders?

 

[varesecrazy]

Could it be that the coil pack that serves 3 & 4 has failed completely now hence it won’t start on just 2 cylinders?

Quite possibly..

 

[varesecrazy]

Intermittent smooth/lumpy. The new leads and plugs hasnt made a noticable difference. My guess is coils next but for the car not to start at all? I would have expected start but missing so no start has me wondering. Also does the lack of mpg info indicate a problem with the ECU?

Realistically you want to ask the garage why that work made no improvement..

They should have ruled out a failing coil pack before your @£100 bill

Does the car make any attempt to start?

I remember how gutless my sons 1.1 was when a coil pck failed..
But it DID RUN..!

 

[rkwheeldon]

Turns over briskly but no signs of firing. I also suspect that the coil pack might have failed. I've ordered two new ones. Fingers crossed!

 

[rkwheeldon]

Coil pack had failed. Engine now starts but runs rough. Diagnostics say injector failure on cylinder 4.
So, 4 injectors ordered!

 

[varesecrazy]

Coil pack had failed. Engine now starts but runs rough. Diagnostics say injector failure on cylinder 4.
So, 4 injectors ordered!

Ok, I would swap plugs, leads etc 1st

At least it runs

 

[rkwheeldon]

New injectors finally solved the problem. So, the plugs and leads were on their last legs. A coil pack had failed and No. 4 injector had failed.

 

[varesecrazy]

How old were the plugs?

This is the era where tired plugs took out the spark driver in the ECU,
so it could have been worse

 

[rkwheeldon]

Unsure but looked as though I should have changed them some time ago. I was lucky with the ECU then!