Technical Misfires

[Pagan Lord]

Hi My Fiat Seicento 2001 started to intermitantly run badly losing all power. Took it to a garage and it said coil one faulty. I have now changed the coil, leads and spark plugs and it still runs badly only it is now all of the time. Has anyone had something similar or have any suggestions.

 

[jatkinson]

Hi welcome to the FF

Try your lambda sensor, i know ive had a few missfire faults that ive sorted by Changing the lamda , you could see if it is the lamda by unplugging it and see if the missfire clears up

 

[Pagan Lord]

Hi Thanks, i will give it a go.

 

[Pagan Lord]

Tried the Lamda still no joy. Looks like two cylinders not firing despite a spark being generated. Both Cylinders connected to the same coil pack but I have changed the coil pack and it makes no difference. As stated earlier I have also changed the HT leads and the plugs and I do not think its the cylinder head as there is no muck on the oil cap and the oil on the dipstick looks clean. Could it be the ECU? Any thoughts?

 

[Pirus]

Two cylinders not firing though spark is still being generated for them?
Which cylinders arent working?
How have you tested the two spark plugs?

Depending on the cylinders, if youve got spark then I'd of thought we'd be looking at the two other easy things needed for combustion - fuel and air.

No other fault codes have been generated?
Did you fully remove the lambda, or just unplug it? Was this the pre or post cat lambda you removed?

Sorry lots of questions but trying to get a good background to help

 

[Pagan Lord]

Hi Pirus,
Thanks for this.

It is Cylinders 1 and 4 not firing but yes there is a spark and a good one at that and I have changed the spark plugs. I just unplugged the lambda and frankly I did not know there was a post cat lambda are you suggesting it has to be fully removed? When I remove the leads to cylinder 1 followed by 4 the engine still runs the same (badly) disconnect 2 followed by 3 and the engine stops on both occasions. From your note sounds like you suspect the injectors? The code just told us coil 1 and have now replaced both coil [packs, the leads and the plugs......

 

[Pirus]

Okay so 1 and 4 arent firing.
So next step is are the injectors working. Can test with a multimetre and you could try and crank it without the leads in the cylinders and then pull a spark plug out and see if it stinks and is covered in petrol.
With the lambda, i was just checking you just hadnt removed it from the exhaust and had it in fresh air.
Where abouts in the UK are you? if you're nearby someone might be able to come and help

 

[Pagan Lord]

Pirus, You are a star. Having replaced two injectors its now running like a dream. Thank You

 

[Pirus]

You're welcome. Had a few other suggestions to work through if they were working