Technical 2013 Panda 1.2 rough idle and failing emissions test.

[jackwhoo]

Just had a call back from the garage.

They also put the new coil pack back on, no change, did some more diagnostics and found one of the injectors not working.

It's bee replaced and MOT passed.

more updates later.

You are going to gain 25% more power now it will run on 4 cylinders rather than the 3 it has been running on

I was very wrong about having a big hole in the exhaust causing the high emmision lambda reading , the cylinder with faulty injector was pumping fresh air into the exhaust causing the very high calculated reading by the mot test machine.

 

[varesecrazy]

You would have anticipated 1 very clean spark plug if that were the case..


Great to hear its an MOT pass..!!

 

[plasmahal2020]

Thanks to everyone who has chipped in.

They used a process of elimination after clearing the codes on their diagnostic machines.

Checked plugs, leads and did compression tests, all came back OK.

Checked voltages and signals from the ECU and seemed all normal.

They then checked all the injectors and one came back dead.

£135 for the injector and £110+£49 VAT for labour and no charge for the third MOT.

We can now move on.

 

[Herts Hillhopper]

Thanks to everyone who has chipped in.

They used a process of elimination after clearing the codes on their diagnostic machines.

Checked plugs, leads and did compression tests, all came back OK.

Checked voltages and signals from the ECU and seemed all normal.

They then checked all the injectors and one came back dead.

£135 for the injector and £110+£49 VAT for labour and no charge for the third MOT.

We can now move on.

As I commented - like my older model, faulty injector

 

[R1NGA]

Very glad to hear this is fixed and in truth we were all pretty close in one way or another. Injector health is often overlooked and whilst I'm not a general fan of the big engine cleaning treatments like CataClean that Edd China provides (other services available), I do believe that it's worth sending injectors off for a service once running issues appear unexpectedly if they're more than 6 or 7 years old.

One of the best threads for ages

 

[plasmahal2020]

The garage gave me the faulty injector and no cracks or obvious faults, just electrically failed although i suspect it could have been intermittent.

 

[jackwhoo]

My previous (2005) 1.2 4x4 did something similar... turned out to be a crack in the plastic where one of the wiring plugs connected to the fuel injectors on the fuel rail. If you try 'wiggling' each connector there should be very little movement. In my case, three had little and one wobbled a lot. Was worse when hot. I bought a complete rail with the four injectors on it from an on line breaker (for very little money!) - and swapped the individual injector from that 'new' one to the original rail. Worked a treat! Exchanged the car a few months later... for a 2013 MJ 4x4

Worth quoting to show how close herts was way back in thread.
Kudos to herts hop

 

[Herts Hillhopper]

Worth quoting to show how close herts was way back in thread.
Kudos to herts hop

Thanks! My long experience of mending things (not just cars) is that generally, the cause of things that behave ‘intermittently’ tends to be an electrical issue - broken wire, dirty contact, duff solenoid. My other car (a Volvo) has been behaving oddly, going into limp mode but with no warning lights... and this too turned out to be a break in a small wire connected to the DPF pressure sensor. My dishwasher too, where all the signs pointed to a failure of the main ‘brain’ turned out to be a break in a thin wire in the door, that flexed back and forth each time the door was opened and eventually snapped.

 

[Pugglt Auld Jock]

Thanks so much for keeping us updated. I echo what has already been said and was sitting on the edge of my seat awaiting every post!

 

[Herts Hillhopper]

Just heard back from the garage.

Their diagnostic equipment is pointing to a coil pack issue.

While i fitted a new magnetti maerelli unit, it did not solve the issue or get it through the second emissions test, so i refitted the old one.

I have given them the new coil pack and they will fit again tomorrow and re-run diagnostics.

I did suggest they may want to look at plugs and leads even though they were replaced last year but i realise they may still have developed a fault since then. I don't have any equipment to test these parts.

This shows the 'problem' with OBD diagnostics. The ECU didn't detect the fuel/air mix being ignited (the 'knock' sensor didn't detect an explosion), so the system concludes that there was no spark present. But in fact, the spark was there, just there was nothing to ignite. The effect is the same - no 'power' generated by that cylinder, but the cause not that the 'diagnostics' points towards. There's a lesson there: ignore the fault codes (although do let them guide you a bit - was the faulty injector on cylinder two where you previously saw a fault code?). Instead, go back to first principles for a petrol engine - check for a spark, and if that's there and the issue remains, then its almost certainly lack of fuel. Yes, it could be stuck vales or damaged valve seats - but in this day and age, is that really likely? (And no, I'm not that old - just like to consider the 'most likely' (which is often the most simple) cause first. Glad its all sorted... great thread and shows the value of forums such as this.

 

[murphyv310]

Excellent news.
This has been a great thread, with good advice.
Like Mr Hillhopper, I like repairing my own things, a great way to learn.