1 hour ago, Wino said:

Here's the wiring:

 

Z19 is the integrated heater in the sensor G39. Continuous 12V goes onto one end of it at sensor pin 5 (blue/red), PWM controlled ground connection from ECU pin 5 to sensor pin 3 (brown wire) to heat as required to get desired temperature. 

I seem to remember the little external resistor (rectangle between pins 1 and 2) is some sort of 'select on test' tuning thing fitted as it's tested in the sensor factory. Lives under that cover that fell off yours I think.

Google will probably be able to tell you far more than I can about what the four thinner wires do.  Some current is varied by the ECU to keep something static, and the oxygen content can be inferred from the size of that current, is about the extent of what I remember.

 

Test instructions for heater resistance: -

 

At ambient temperature the resistance of the heating element
should be approx. 1...5 . The resistance increases
considerably even if the temperature rises only slightly

 

 

 

Thanks very much. So test for 12 v (ish) supply to sensor from the brown wire at the harness terminal. Then test for resistance across 3 and 5? 

No, 12V supply from blue/red on loom connector, but fuel pump relay needs to be on, so at least ignition on, not sure if that's enough..

Yes resistance from 3-5 of sensor connector, with it unplugged from loom.

 

TBH, any fault here would generate a fault code, I'm near certain.

Lost a post, apologies if I'm repeating myself. Yeah, 11.8 volts from blue/red wire with ignition on (fuel pump had shut off by this point, however). 2.6 ohms resistance 3-5 at ambient temp. Ordered some sharp little probe ends so I can test at the back of the plug for a reading when its running.

Think you are probably right. Resistance between 3 and 5= 2.6 ohms ambient temp, permanent feed ignition on (but fuel pump shut off having run for a few seconds to charge the system) from red/blue 11.8v. I tried to get a reading from the other terminals on the harness plug but they were odd: either very low, below 1 volt or, in the case of the terminal that would join no.1 on the lambda sensor plug that I think is blanked off (as your diagram also suggests), extremely high:107 volts.

Nothing wrong with heater then.

The latter high reading is probably a function of the multimeter. I've never had one that self-ranges before and, once the earth clamp is attached to the battery, it just sits there showing random voltages on the screen until its positive lead is connected. To check it wasn't bust I tested the battery voltage and got a steady 12.5, engine off.

Seemingly not. I guess I need to check the same functions on the downstream one. Now second guessing myself for too long, there can be no way an incorrectly fitted cambelt could account for this? If that were the case a misfire would be constant, it wouldn't drop in and out as it does?  

46 minutes ago, gallaghermartinpaul said:

Now second guessing myself for too long, there can be no way an incorrectly fitted cambelt could account for this? If that were the case a misfire would be constant, it wouldn't drop in and out as it does?

Dunno, to be honest. It's the simplest explanation, and they often turn out to be right. 

Why was the cambelt changed, just routine preventive maintenance? No issues before then?

No, just routine. However...having just looked I've found something strange.

 

Driver side wheel and wheelarch liner off to expose the fanbelt pulley, I've removed the plugs and turned the motor to align the mark on it between the two plastic notches on the timing case labelled '0' and '2'.

 

Then trying to use the pulley locker to lock the cambelts together that I used to change the belts last  time I've found it won't fit. You can remove the two pins from the tool's spacer plate and insert one into the camshaft governing the inlet valves. When you do that, it and the crankshaft (meaning the fanbelt pulley/timing case marks) are in alignment. But then you can't get the second pin into the wheel for the exhaust camshaft under any circumstances; looking in from above with a torch it's apparent that its top edge is only just on the lower lip of the lug in the head it's meant to slot into. If you then remove the first pin from the outer wheel (inlet valve cam) and turn the motor so that the exhaust cam pin will go in then the first one won't.

 

More seriously, by the point the pin is onto the small wheel for the exhaust cam, the timing mark on the fanbelt pulley has moved good 15-20 degrees past the marks on the timing cover. I recall from doing them last time that it was fiddly to get both cams and the crank aligned but it was doable with patience. This is different.

When the light fades a bit I'll take some pics and post them in case I've been at all unclear.

 

What I'm not sure on is how this would cause the effects I'm seeing. Inlet valve timing would be normal (obvs) but exhaust out by a tooth, presumably? How serious is this and how come it's only causing probs when warm? I appreciate until then it's running fully fuelled and the ignition timing will probably be advanced or retarded to optimise starting etc. How would the valve timing being out cause intermittent rough idling (if revved it runs normally for 5 seconds or so, then goes back to spasms of shuddering every 5 to 10 seconds) is the ECU attempting to compensate for what it senses but only able to do so much before a misfire occurs?

 

Apologies if I've got a lot of questions but I need to take it back to the garage and be very clear about what I think is wrong and what effects it is having. My German is OK but naturally imperfect, so when you tell people stuff they don't want to hear they've a tendency just to try to talk right over you. The motor trade (and I worked for recovery services for years, I might add): seems some things are the same wherever you go...

*should read 'into the small wheel for the exhaust cam', i.e; it's passed through the toothed wheel and into the lug in the head. Locked at TDC.

Pictures. Of the position of the fanbelt pulley relative to the timing cover marks. First one with inlet valve camshaft locked to TDC. The second slightly fuzzy one is with the locking pin for the exhaust camshaft inserted. The third one shows the empty lug where the pin should insert into the head to lock the exhaust camshaft but can't, the inlet valve cam being locked at TDC. The final shows from above if you what happens if you rotate the engine to the point shown in the second image: the pin won't enter the lug behind the inlet valve camshaft, thus it sticks out beyond the fully inserted one in the exhaust cam. If this is what it seems, this is a major error by a dealer, right?

I've yet to do a belt on one of these, but it sounds like you know what's right and what isn't; and currently it isn't. 

Yes, it's a major error, the exhaust cam is not timed correctly, as you say, it's a whole tooth out.

Show the dealer the error and ask for it to be redone correctly.

On 27/06/2020 at 18:05, sepulchrave said:

Yes, it's a major error, the exhaust cam is not timed correctly, as you say, it's a whole tooth out.

Show the dealer the error and ask for it to be redone correctly.

Yep, turns out that that's exactly what it was. Dropped the car off yesterday and spoke with a guy in the workshop who assured me that both cams and the crank are locked in place by their Skoda special tool, that it was impossible for it to be fitted wrongly and that it was likely a fuel injector. etc, etc. Got a call back just now to say yes, they had actually fitted it a tooth out and wasn't it all rather embarrassing. This, as I'm sure I've said, from the main VW/Audi/Skoda dealer here in Berlin. Now in the process of getting an admission of the error in writing so there might at least be some recourse if the motor blows in the near future. In conversation with a Skoda mechanic in the UK, he suggested 1 tooth out shouldn't have affected the valves, etc; not sure what the obviously elevated cylinder temperatures will have done to the piston and rings. In any case, thanks for your advice guys. As you said Wino, sometimes the most obvious answers are the right ones, no matter how implausible it seems that such an amateurish error could have been made.  

There will be no long term implications since the valves did not hit the pistons.

Hi gallaghermartinpaul.... My wife has an auto BKY engined Fabia too. It sounds like a diesel how rattly the engine is yet it has only done 60K. There is a thread on here about it.... how does yours sound? Also, in neutral or park if you rev the engine & try to hold 2000 revs do you find the revs drop off & it's difficult to control as though there is a dead spot in the throttle?

 

That pipe on the airfilter is a pain, it is really difficult to fit with the grommet. It always worried me that it will fall off & affect the braking performance!

@Zebedee2001, did you ever have a look at the oil separator module on your wife's car?

I bought a (manual) Polo with a BKY engine this year, and found horrors when I checked this item: 

It was so bad that I was compelled to also get the sump off to check the oil pick-up pipe and general 'non-oil' contents. There's a thread about that too here.

 

I'm still intrigued by that pipe to the air filter. Surely there must be a narrow restriction at the point that pipe tees into the main servo hose? (As opposed to there being such a jet or valve at the point it connects to at the airbox). I might have to buy a secondhand servo pipe off an auto car via ebay to investigate.

@Wino - not wanting to hijack a thread...but

 

I did replace the oil seperator - it wasn't actually that bad & looks like it had been replaced before. I did think about taking the sump off but haven't ventured there yet! In some ways we have learnt to ignore the rattling! It was helped by the knocks fromt he suspension but I have since replaced the bottom ball joint one side & both the drop links.

 

The vaccum pipe is bizarre. I don't understand the point in it & it looks like it is bodged in using various bits of pipe etc...

I've got one of the vac pipes coming from ebay now, so will have a look.  To my mind, whatever its function, there ought to be a jet/narrow orifice at some point in that leg to the airbox, or at the airbox, and from a failsafe point of view that would best be at the point it tees into the main servo vac pipe.  With luck that'll be what I find, and it will render the business of it being connected/disconnected from a filtered air source at the airbox irrelevant.  Have you tested brake servo efficiency with it disconnected from airbox versus connected? 

My spare pipe arrived this morning and confirmed my idea of the restriction at that end of the pipe.  I could've probably seen it in photos of that part number in hindsight, but here it is, looking all nice and narrow in the plastic part just beyond where the hoses meet. (hose going off rightwards at 45° is the airbox one, rightwards is towards servo, left side connection to inlet manifold)  I would therefore expect the attachment or non-attachment at the airbox to make no difference to anything functionally, except that it would - long-term - potential clog that very same narrowing with particulates from the air, as it would be sucking in unfiltered air if not connected to the airbox. 

 

 

On 27/06/2020 at 09:49, Wino said:

 

 

On 27/06/2020 at 17:43, Wino said:

On 16/07/2020 at 23:26, Zebedee2001 said:

Hi gallaghermartinpaul.... My wife has an auto BKY engined Fabia too. It sounds like a diesel how rattly the engine is yet it has only done 60K. There is a thread on here about it.... how does yours sound? Also, in neutral or park if you rev the engine & try to hold 2000 revs do you find the revs drop off & it's difficult to control as though there is a dead spot in the throttle?

 

That pipe on the airfilter is a pain, it is really difficult to fit with the grommet. It always worried me that it will fall off & affect the braking performance!

 

 

On 16/07/2020 at 23:26, Zebedee2001 said:

Hi gallaghermartinpaul.... My wife has an auto BKY engined Fabia too. It sounds like a diesel how rattly the engine is yet it has only done 60K. There is a thread on here about it.... how does yours sound? Also, in neutral or park if you rev the engine & try to hold 2000 revs do you find the revs drop off & it's difficult to control as though there is a dead spot in the throttle?

 

That pipe on the airfilter is a pain, it is really difficult to fit with the grommet. It always worried me that it will fall off & affect the braking performance!

Hi, 

Absolutely, sounds much like a modern diesel. And yes, it also has an odd spot at relatively low revs (c1200) where even if the pedal is held in place-by a torch, length of wood, etc-the RPM will fluctuate in 2-3 second cycles by around 200 RPM. No air leaks, new MAP sensor, sparkling throttle body and a clean manifold; no problems shown on my hand-held scanner or at the VW garage locally. Runs fine and will maintain constant revs at tickover or at higher RPM. A mystery...

1 minute ago, gallaghermartinpaul said:

 

 

Hi, 

Absolutely, sounds much like a modern diesel. And yes, it also has an odd spot at relatively low revs (c1200) where even if the pedal is held in place-by a torch, length of wood, etc-the RPM will fluctuate in 2-3 second cycles by around 200 RPM. No air leaks, new MAP sensor, sparkling throttle body and a clean manifold; no problems shown on my hand-held scanner or at the VW garage locally. Runs fine and will maintain constant revs at tickover or at higher RPM. A mystery...

Only consolation being that we hired a brand new 3 cylinder Fabia last year and the effect was even more pronounced.

@gallaghermartinpaul Are you still active here? I have a very similar idle in my BKY polo. It's been like that since I bought it and that was right after the engine was rebuilt after the cambelt went. I'd rode in it before then and I can't remember ever noticing anything similar.

I've tried so many things and I cant cure it. I'm not very knowledgable about cars so I'm confused about how you discovered your misalignment. I want to get stuck in to see if maybe I have the same problem though. I also have full VCDS if that can benefit.

Thanks for any help!