Hello,

 

Found an error 3 days ago:

 

P0303 - Cyl. 3 misfire

P0300 - Random/Multiple Cylinder  - Misfire Detected

No check engine light or any other lights on the dash.

 

Removed the faults (have them in a backup) and did not show up anymore since then.

Strange though, I did a live reading of parameters, for misfire, and seems to have some high numbers of misfires i believe since beginning - 2.5year old car.

And if I hit the throttle hard and go to high RPM's I get 1-2 more every now and then.

 

Is this normal? Should I check something? Could it be the gas although it's Premium 100.

 

Did anyone else read these live parameters? Or it should 0 or close to zero?

Edited 27 February, 20206 yr by ccosmin

In terms of what it's counting, I wonder what 'misfire' technically means?

 

Spark not generated at source, spark plug didn't spark, combustion didn't happen, combustion below normal parameters, injector didn't inject, or a whole host of other things?

 

Don't think I've ever owned a car, new or old, where I haven't detected the occasional misfire.  Unless it's affecting the drivability of the car, I don't think I'd be concerned.

 

If the car averaged out as running at 2,000rpm for just an hour a day, that's 900 hours (ish) over 2.5 years, or in other terms, 54,000 minutes.  54,000 x 2,000 = 108,000,000 fires. Which equates to a successful fire rate of 99.992%.  My simplistic maths are probably squint, but what I'm thinking is 9k in 108m barely registers.

 

Gaz

I did a similar math but different, regardless of the time droven, i's count in average of 10 misfires/day for 900 days. COnsidering nothing is affected, drivability is fine, no errors. When you have in one run many more misfires, it will probably cause the errors to trigger as it happened to me, but not enough to cause check engine light...

So assuming this is normal....

Edited 27 February, 20206 yr by ccosmin

Sometimes too much information is as dangerous as being kept in the dark.  Unless you know the allowed specification then the readings are pretty much useless.  For example does it count as a misfire if you lift off the throttle part way through the firing cycle so fuel is interrupted?  Is your car ACT or is that only the 1.5 models?

Basics.

Remove all sparkplugs, inspect very closely, check the gap.

Since they are out you might as well put in new ones.

 

2 minutes ago, Roottootemblowinootsoot said:

Basics.

Remove all sparkplugs, inspect very closely, check the gap.

Since they are out you might as well put in new ones.

 

 

Why check them if you are replacing???

@Kental  You have all that anyone needs to be a Skoda Technician.   

 

Because you are trying to diagnose why mis-fires.  Looking for issues.

Head for thinking feet for dancing.

 

The OP does not mention how many km covered in 2 1/2 year.   Spark plugs that are having and early demise can cause Ignition Coils to also go early.

5 minutes ago, Kental said:

 

Why check them if you are replacing???

If the gaps are wide then you know it is the plugs causing the misfire. Also if the electrode is worn that can cause misfire. The colour of the plug can also be an idicator if the cylinder is running lean or too rich. It might point to a slightly blocked or worn injector etc.

Edited 27 February, 20206 yr by Ecomatt

Just now, Roottootemblowinootsoot said:

@Kental  You have all that anyone needs to be a Skoda Technician.   

 

Because you are trying to diagnose why mis-fires.  Looking for issues.

Head for thinking feet for dancing.

 

The OP does not mention how many km covered in 2 1/2 year.   Spark plugs that are having and early demise can cause Ignition Coils to also go early.

 

As the OP says there are no warning lights, wouldn't most techs stop there and say "no fault found, thank you that is £100 + Vat for the diagnostic"!!!

You do not always get fault codes if not enough misfire to log in a cycle.   That is not a push bike.

 

Sometimes you want a Mechanical Engineer and not a Technician / Fitter with a NVQ. all the gear and little idea.

Edited 27 February, 20206 yr by Roottootemblowinootsoot

2 minutes ago, Ecomatt said:

If the gaps are wide then you know it is the plugs causing the misfire. Also if the electrode is worn that can cause misfire. The colour of the plug can also be an idicator if the cylinder is running lean or too rich. It might point to a slightly blocked or worn injector etc.

 

Sorry, yes I was being a bit flippant, but as IamGaz said it is 99.992% firing normally, are the internal readers really that accurate, the average MPG one certainly isn't!!!

The OP said he is using 100 / 100+ Octane.   The misfires can be there under higher loads, under acceleration.

 

It is not uncommon for 1.4 TSI Twinchargers with the common one bad spark plug to be running 95 ron and no misfires being detected, 

but a new owner uses Super Unleaded / 99 ron and gives it a bit of a thrashing and then the car goes into fault mode, ECP or Exhaust Emissions light or both.

The fuel never caused the issue, the plug with the already burned tip, or fouled plug was in for thousands of miles and just not worked hard.

@Roottootemblowinootsoot you'll be glad to know I run 99ron & check my plugs regularly 😂😂😂😂

@themanwithnoaim  Do you really or are you a little kidder, are the original plugs still in?  You never struck me as been that hands on, more a leave it to someone that knows about mechanicals.

http://briskoda.net/forums/topic/477945-dsg-oil-leak

I hope you check them because you are running non factory approved engine management or hardware and do not want any engine failures when driving like a man with no name possessed on that private roads.

Edited 27 February, 20206 yr by Roottootemblowinootsoot

On 27/02/2020 at 13:26, Roottootemblowinootsoot said:

The OP said he is using 100 / 100+ Octane.   The misfires can be there under higher loads, under acceleration.

 

It is not uncommon for 1.4 TSI Twinchargers with the common one bad spark plug to be running 95 ron and no misfires being detected, 

but a new owner uses Super Unleaded / 99 ron and gives it a bit of a thrashing and then the car goes into fault mode, ECP or Exhaust Emissions light or both.

The fuel never caused the issue, the plug with the already burned tip, or fouled plug was in for thousands of miles and just not worked hard.

 

From his first post, the misfires are pretty even across all 4 cylinders so does that make it less likely to be a dodgy plug?

Sorry, was away these days, but I have 26.000 km done, and on my last 250km drive I had around 50-70 misfires per cylinder, on the counter. Sport/ECO/Normal driving....