Skoda Fabia II, 1.4 16v 86HP BXW 2008 - Ignition loss in one cylinder, error codes P1112 and P0301

Hello.
The case concerns the skoda fabia II, 1.4 16v 86HP, BXW engine, 2008. mileage 140kkm. Here is a brief history of "maturing" faults.

June - July 2016
Noticed very sporadically and hardly perceptible, occurring every few, several seconds single "vibrations" transferred from the engine to the cabin felt at low speed. Firing dynamics, flawless combustion.

30/11/2016 - first check on the board, error canceled, everything is ok except for the "twitching"
17520 - Oxygen (Lambda) Sensor Regulation: Bank 1: System too Rich
P1112 - 000 - -
Readiness: 0000 0000

12/01/2017 - second check on a board, error canceled, everything ok except for the still "vibrations"
17520 - Oxygen (Lambda) Sensor Regulation: Bank 1: System too Rich
P1112 - 000 - -
16685 - Cylinder 1 Misfire Detected
P0301 - 000 - - - Intermittent
Readiness: 0000 0000
mechanic diagnosis: replacement of candles with new ones (they already deserved it) and replacement of the coils with places with another cylinder and drive for a while as it appears again, it needs to be repaired

24/01/2017 - third check and the following errors
17520 - Oxygen (Lambda) Sensor Regulation: Bank 1: System too Rich
P1112 - 000 - -

17519 - Oxygen (Lambda) Sensor Regulation: Bank 1: System too Lean
P1111 - 000 - - - Intermittent

16685 - Cylinder 1 Misfire Detected
P0301 - 000 - -
Readiness: 0000 0101

After the third check, the car clearly already has a telepiece engine, it seems to be driving but it lacks power. Clearly mussels on Pb and cold engine when accelerating, more vigorous gas pressure causes a noticeable throttling of the engine, warmed up is slightly better. After firing on a cold engine runs evenly without throwing errors until "overheating" then "vibrations" appear.
On warm, "vibrations" are felt all the time, ignition loss occurs only on 1 cylinder both on Pb and on LPG, but on LPG it is much more intense, the change of coils between cylinders does not matter. The car fires normally from the shot. Engine operation deteriorates with its warming up, the warmer it is, the worse. Compression pressure on all cylinders equalized and is above 13.6-13.5, so healthy as a bull.
Where do you advise to start replacing components so as not to charge at unnecessary costs probe for the first fire?

The exhaust is unobstructed / checked?

The car has not been checked yet only yesterday afternoon it went to a mechanic. I do not suspect, however, a blocked exhaust (which does not mean that this is not possible) but the engine does not burn a gram of oil, the throttle was always only slightly smoked, no deposits and carbon deposits were ever there. In addition, the engine spins with no major problems.
Well, please check the exhaust.

PS I just talked to the mechanic by phone and at the moment they are replacing the Pb injection rail with another one. Until now, they have checked electrically and all voltage and signal values on the probe and injections are and are normal.
Nothing is known yet.
I wonder, however, that on LPG there are more ignition drops than on Pb and the engine shakes more. If it was bad on LPG and 100% on gas it would be much easier to choose the direction of the search.

I think so maybe there is a frayed cable somewhere and it vibrates, shorting the circuit and hence I combine these problems in different ways ... I always have to have pioneer cases, nothing typical.

Something else I remembered the candle on the 1st cylinder was black with soot after the thread, the other cylinders 2,3,4 candles with clear correct coating. Porcelain insulating the central electrode of all 4 candles as white as a box from the box no raids.
Even while the engine was running, the work of the cylinders was monitored and the 2,3,4 cylinders had a zero value (I do not know only what parameter was meant but the topic experts will know) and for 1 value it increased in a dozen or so seconds from 0 to over 100 times, and the chart was like the teeth of a saw, growing and rocking to zero. As if something was reset or exploded in this cylinder and in time of these drops with an irregular shift in time, you can feel these "twitches" just not every time they coincide but I think it results from the differences in refreshing the information transfer to the diagnostic computer.
Maybe in this cylinder there is no fair spark or it is not every time and there is periodic ignition is possible? Maybe the ECU was gone?
I apologize for the amateur painting but I try my best to describe everything.

What pressure on cylinders?

If the compression pressure is as you write, (candle, coil, injector) checked then it remains to x-ray the bundles and rather than pull off the head and look for a mechanical fault (valve, spring, guide ...)

Added after 3 [minutes]:

Was the camshaft replaced in this car?

Pressure evenly on all cylinders 13.5 - 13.6.

Camshaft replaced in May 2015 with a meter reading of 104,200 km. Now it is 140,800 km.

The first twitches began to appear at the turn of June-July 2016 at a mileage of about 130,000km. "By ear" no signs of abnormal operation you can not hear the engine running only noise I know that the suspension of the valve can not be heard especially as it occurs sporadically. But this can be a clue and cause of incorrect combustion in 1 cylinder.

The engine can sometimes go out in the summer in the climate when you reach the intersection at ease (if it matters) - also no one could bite this problem comes out that TTTM.
From other forums, Skoda Rapid, SEAT Ibiza and engine-related cars, i.e. 1.4 16V 86 HP goes out to hundreds of users and no one has found a solution. I've read hundreds of ideas and none are effective.
Well, but I do off top in my own thread.

Gentlemen, let's return to the theme ...

Pull off the rollers and check the cams, swap the tappets at once.
There they liked to wipe the rollers but then they usually wave revolutions.
Did you ride the PB alone, or is it catching any mistakes?

The revs on the tachometer are even, the pointer does not fluctuate according to the computer fluctuations between 780-820 rpm, the engine runs quietly only.

Yesterday evening I talked to a mechanic and says that the damage to the gasoline injector on the 1st cylinder came out and the mixture was too rich.
He claims that the gasoline injector "hangs up" and does not work properly, then the computer tries to correct the composition of the mixture to the maximum value of corrections that can be made, catches an error and after switching to LPG it does the same on the gas injector and hence these vibrations, because in some at the moment the corrections are restarted and an attempt to return to the optimal values is still in progress in the loop. If, in fact, the gasoline computer then controls the gas injectors directly or indirectly, or even has an effect on the LPG system controller, then maybe this error is later transferred to the LPG injector and due to the fact that gas is a slightly different fuel than gasoline, these vibrations and silting on gas is more noticeable.

My question here is: if petrol injection gets dirty, why can't LPG get the correct settings? In fact, the ECU "remembers" this error rigidly?

As for one more thing, he told me that the engine can not be screwed in revolutions "to the section" only the tip of the tachometer comes under the red field and then as if there was no "forces" there is no typical sections only as if damping, mulching (I do not know how to specify) turnover according to it only indicates a malfunction of the fuel system because electrically it claims that everything is fine.

As for the mechanical defects of the timing system at the moment they are excluded by the mechanic, auscultated the engine and claims that picking the head will be the last resort.

I do not know this so much and it is difficult for me to determine whether this is how the computer actually works. What he says has a logical sense but is it really so?
What do you think about it?
The mechanic confirmed - as colleague Grala1 wrote - that if there was something with the valves, it would wave and revolved once in a 1.4 VW engine.
For now, I let him act and let him replace this injection.

Bambek wrote:

I just talked to the mechanic by phone and they are currently replacing the Pb injection rail with another one

So they checked the injector before or not? The easiest way was to transfer the injector to another cylinder and it would be known.

mario 77 wrote:

Bambek wrote:

I just talked to the mechanic by phone and they are currently replacing the Pb injection rail with another one

So they checked the injector before or not? The easiest way was to transfer the injector to another cylinder and it would be known.

They checked the TEXA diagnostic system and it turned out that the mixture was too rich and the injector on the cylinder was damaged. For now, the car is not complex, because it turned out that the injections are from another engine and there is nothing to change.

I do not know if the injection was transferred to another cylinder, I think so since he claims that he is sure of the fault and the coils were also replaced at the beginning.
I do not stand there and do not look at what is happening at the moment but as I have known it for a long time this is a mechanic of those who rather want to diagnose the problem well first and does not touch blindly exchanging subsequent elements, he already has many strange cases healed successfully let's give him another chance

The latest news from the workshop, unfortunately, not very successful.
Substitutions were coils, injection, candles, probe and vibration still occur the same and still error in 1 cylinder.
A sad decision was made, the head was up, only valves were suspected at the moment, mechanical damage to the cut rollers or a problem with carbon deposits on the shafts.

Before the head, let them take off the rollers and look at the springs on the valves.

Fights, springs and valves will do the trick without a head check.
Head disassembly is a last resort.

Thanks for the advice, gentlemen, for following the topic and helping you. Thank you so much.
Tomorrow morning I will go and talk what and how. Today, they haven't done anything yet for the car.

The reason for the fault were burnt out valves, very large amount of carbon deposits in the channels. One of the valve stems looked like a mouse was eating it. I was surprised myself that after 140kkm the head could be so devastated, the fact that from the first kilometer the car had factory-set gas.
The mechanic says he is very surprised that the engine kept the compression so high and even.

Maybe it's the fault of a poor landi renzo installation, what do you think?

The head has been completely regenerated with the replacement of valves, guides and sealants, etc.
The car is currently being assembled at the workshop, I hope that was it.
I will let you know how the procedure was successful.

Bambek wrote:

The mechanic says he is very surprised that the engine kept the compression so high and even.

I have already done this several times, the pressure measured several times and ok, and after removing the head a surprise. greetings

Well, all signs indicate that after repairing the pest will recover. I'll call you when I pick up the car for today was not ready because I had to do the timing, 40kkm only but as they say "go cow let go and body".

Edition from 07.02.2016 at 8:00.
Auto made engine on Pb works perfectly without any interference, no vibrations.

On LPG, however, the check crashes and the same error numbers as before on the 1st cylinder. Feel the continuous uneven operation slightly different than before the regeneration of the head, now it is light but nevertheless noticeable and continuous shaking and "wheezing" from the exhaust. After returning to Pb, everything stops and works perfectly again.
Today visit to the gasman, suspicious LPG injection rail.

Edition from 07.02.2016 at 21:55
After visiting the gas supplier. Completely fallen LPG injector on 1 cylinder. Mileage 80kkm. Once, at 60kkm, the strip fell, but it was replaced with an identical one under the warranty. Now she fell for the second time after 80kkm it seems that this is some terrible crap.

The strip is landi renzo OMEGAS "green" exactly as in the link. I am sorry but I can't add a 24kb picture in the size of 24kb error 500 crashes.
https://www.google.pl/search?q=omegas+landire...2F%25252Fwww.agsiedlik.pl%25252Fzestaw-landi- Renzo-4-cyl-reducer-li02-injector-rg1-4 cyl-green-omegas-i1562-k386.html & source = AI & pf = m & fir = riGdFrhIY2HpHM% 253A% 252C0HzySBuRYINYJM% 252C_ & ultrasound = __ 1pk__N6cnFQBE8zicHRvQGy9W9Y% 3D & BIW = 1280 & BH = 654 & ved = 0ahUKEwjwzJ7P9_7RAhXMWCwKHWZ4B_gQyjcILg & ei = xzyaWLDNEMyxsQHm8J3ADw # imgrc = riGdFrhIY2HpHM:


Scared me a little price because he said that such an injection rail in the original costs about 800 PLN IMO is a lot.
All in all, he said that he would choose something different and the costs would be between PLN 400-500 with labor, but he had to do something with the wires. I do not know much about these gas matters, but looking at prices on the network, you can actually find strips for PLN 800, but does it really have to be mounted here?

Hello.
Today I picked up the car from an lpg mechanic. The LPG injection rail has been replaced. The engine runs smoothly and without any vibrations. It switches to gas unnoticed - there was a tug on the old bar - now there is butter.
Tomorrow, jump on a longer route.

I am asking for a non-closing thread for a few days and the fork knife will be born ... hopefully not.

Once again, thank you very much for help, comments and accurate diagnoses that allowed me to solve the problem faster.
I will tell you guys that the electrode rulez !!!