NCT (MOT) very high emissions. Test failure

[Grainne O']

Hi, Guys, I think I need some extra help here.... I've looked around but no thread exactly fits right so I'm starting a new one

This is the story;

My car's an Octavia mk 1, year 2000, 1.6 petrol injection, AKL engine with 133k miles on the clock.

She's had idling and emissions problems for a few years now but now the test is upon me again and it has gone out of control.

This is what has been done to her so far:

-airflow meters change (two - brand new genuine skoda one fitted over a year ago only; barely scraped over the last emissions re-test)

- tested this past march: could not test emissions as the throttle control reported faulty, but the guy told me something about readings being sky high anyway ( he wasn't too clear, just told me it was knackered, more or less)

-taken to the mechanic (thankfully a friend otherwise it'd have cost me I don't know how much so far)

Cleaned the throttle body completely as per this site; put some fuel cleaner stuff in; idling greatly improved

At this stage the lambda sensor packed in completely (tons of white smoke and returned a lambda sensor permanent fault)

Bought a new Bosch sensor, fitted on the car last week, system ok at low idle but returned another fault at high rpm's

This is the fault according to Ross-Tech:

*00537 - Lambda (Oxygen Sensor) Regulation: Upper Limit

Possible Symptoms

Lambda Control inactive

Engine running rough

Possible Causes

Wiring and/or Connector(s) from/to Lambda Sensor(s) faulty

Lambda Control/Sensor(s) faulty

Injector(s) faulty/blocked

Fuel Pressure Regulator faulty

Fuel Pump faulty

Fuel Tank empty

Possible Solutions

Check Lambda Control/Sensors

Check/Repair Wiring and/or Connector(s) from/to Lambda Sensor(s)

Check/Replace/Clean Injector(s)

Check/Replace Fuel Pressure Regulator

Check/Replace Fuel Pump

Check Fuel Level*

We haven't bothered with cleaning the injectors yet, my mechanic doesn't look to keen to start on that if it's not the problem...is it a big job? (the sensor is new and the correct part for my engine so the wiring is too obviously) we ran the test 2 or 3 times and the fault comes back, btw.

Anyway, I read about dirty spark plugs as well and we also changed them last week (wrong ones were fitted on and they were decomposing), and this fixed the rough idle 95% of the time anyway (still goes off 5% of the time for no reason), the smoke looked and smelled clean so off I went to the re-test.

[Let me add here that she is or was burning oil ( oil tank was more or less empty when we checked it there after about 7000 miles post service; I've no idea now the lambda sensor is changed). She is burning absolutely NO coolant and the old sensor was covered in a dusty black powdery covering and not a trace of white so my mechanic ruled out a head gasket problem]

These are the results of the re-test this morning; at least I got a reading this time

engine/oil temperature 91C (he had her for ages and ran the hell out of her; she was as hot as can be and he tried his best)

Low idle: CO 0.15 vol% PASS

HC 182 ppm N/A

High idle: lambda 0.83 [0.97/1.03] FAIL

CO 5.50 vol% [

[Grainne O']

------------

Edited 21 May, 2012 by Grainne O'

[Grainne O']

oops, wrecked the html code with an illegal character and it won't let me edit the initial post. Sorry ^^ here's the rest

Low idle: CO 0.15 vol% PASS

HC 182 ppm N/A

High idle: lambda 0.83 [0.97/1.03] FAIL

CO 5.50 vol% [ less than0.30%] FAIL

HC 990 ppm [less than 200ppm] FAIL

That's nasty now; and it seems linked to that high idle fault we returned since she passed the low idle test?

I read about a golf getting the same symptoms and temp sensor was mentioned (we couldn't really locate it like a bunch of idiots and it's safe to say anyway it's never been changed), but like most people the guy never bothered to post if the fix had worked or not. Can that throw off the emissions *that much*?? no other fault than this one is returned, and I've no dashboard lights at all, but that wouldn't mean all that much

The nct guy doesn't seem to think it's a cat problem, I asked him, he said no, he thought it was *something else*. I'd rather not get a new cat so I'm hoping he's right. The car isn't noisy at all I don't think? I doubt there are holes and the underside is very clean tbh.

She's a great car and goes really well and is really clean, so I'd like to be able to keep it and fix the damn thing.

Ok, that was a brick of a post but I've tried to mention all I could think of. Any other questions I'll try to answer.

If you managed to read it all, I and my mechanic'd be grateful for tips saving me some money ^^

[mac11irl]

It could possibly be the CAT if it was running bad plugs. My old car had a cracked HT lead so an intermittent misfire for a bout 3 months and a broken Oxygen sensor on the exhaust side of the engine.

Wwent for its NCT and failed the emissions miserably. New CAT needed, as the unburnt fuel and poor fuel/air mix from the oxy sensor fault, being dumped into it had wrecked the CAT.

Twas an expensive job for a new one too!

[Grainne O']

Tnx mac, I'd rather it wasn't the cat but yeah, I read faulty sensors can wreck it. At the same time I've read too many posts saying changing the cat did zero so I'm going to try that as a last ditch resort only.

Further reading all over the web has led me to decide to change the coolant sensor (and the map sensor for good measure, all those sensors are old as dirt), change the air filter and service the car (the oil is contaminated and a mess and I'm going to put my foot down so it gets done lol, around here it's harder to get things done when they need to be than get ripped off for getting things changed when they don't need to be; "it'll be alright" is the motto)

and see where we stand then.

Would you experts think it a good course of action to start with?

The hardest part could be to find somewhere to test it, we usually use the NCT itself to sort out right from wrong as mac would agree here in Ireland...saves us fixing things we can get away with

[Dave And Lolli]

Have you tried putting some fuel/cat cleaner through it and giving it a good blast? my vectra had similar issue with high emissions, stuck some cat cleaner through it an passed with flying colours...

[Grainne O']

Yeah....didn't work. Were your emissions this high though?..I have 15 times the allowed CO amount and 5 times the HC amount :(

[Raf_]

Haven't a clue what my emissions test was and my friendly MOT station did it 4 days before they saw my car lol

[Dave And Lolli]

Yeah....didn't work. Were your emissions this high though?..I have 15 times the allowed CO amount and 5 times the HC amount :(

I was getting those sort on idle. as had replaced cat, one from Kwik fit. 2.5 v6

[Grainne O']

The thing is I still have that rough idling sometimes (though 2 years ago we started at tractor rough so it's really little now), but it happens mainly after the car has been revved a bit, so I'm hoping that indeed the temp sensor is just banjaxed and sends cold readings to the car all the time, explaining that ludicrous waste of fuel when warm, and the 00537 fault but the ok reading at idle (and no fault - we got this much fixed at least lol).

The car's running hasn't been right in years but I was just told it was nothing by a previous mechanic plus I didn't have the cash anyway; now is the time of reckoning :|

[Eccentric Toast]

I would try the fuel cleaner it's the bees knees in my opinion, it increased my mpg by nearly 10 and the car feels like its a lot more smoother and responsive but that could be just me. There is a product Dipetane it's excellent!

Edit:

Sorry didn't see you were in Ireland.

Here is their website http://www.dipetane.ie/

And you get it in any good Petrol Station I've seen it in Applegreen and GSF

Its all over boards.ie about it getting people through the NCT just have to give the car a good run before bringing it to the NCT test centre.

[Grainne O']

I'm sure she was dosed with the stuff before the first test but I'll be sure to do it again when I book her in again! Even if she ever gets right the system must still be totally saturated with crap so it's a good idea I'd say

I've finally paid attention to the temperature needle this morning, and it's fairly erratic. Takes forever to get up to 1/8th of the gauge then goes *back down*. Went to get coffee at the local station and when I switched her on again after ten minutes the needle was suddenly over a quarter, when she was barely at an eighth when I got there, then she managed to drop again a bit while driving to home (800 yards away) I'm sure that's not normal.

The temp and map sensors are ordered anyway! cross fingers! Thanks for all the help, if anyone else has experience with this stuff I'd love to hear it

[Grainne O']

The two sensors (coolant and map) have arrived, getting them changed in a bit and then emission test somewhere where they do it...if it's still way wrong and I still get that error code or another then I'll look into changing the cat I suppose.

Unless someone knows of *more* sensors that directly affect emissions?

After a few days of really monitoring the water temperature gauge, it is definitely erratic and obviously on the way out so that can't be helping

[rk696]

Have you tried changing the fuel filter? It's not a service item, so will probably never have been changed. Worth giving it a shot for the few quid it costs.

As for the temp gauge, it could be the sensor, or it could be the thermostat that's stuck open. That would explain why the gauge takes a long time to go to 90. It should stay spot on at 90.

[Grainne O']

No, I damn well forgot about the thermostat. Is there a handy way to check its state?

Got the temp sensor changed and had a perfect idle there for a while, but high idling is now throwing *different* faults and I'm not sure it has done a whole lot for it.

She is now showing lambda lower limit 00537 fault, which is the reverse of what it used to be (upper limit),

00537 - Lambda (Oxygen Sensor) Regulation: Lower Limit

Possible Symptoms

• Lambda Control inactive
  
• Engine running rough
  

Possible Causes

• Activated Charcoal Filter Solenoid Valve 1 (N80) leaking/sticking
  
• Injector faulty (not closing completely)
  
• Fuel Pressure Regulator faulty
  

Possible Solutions

• Check/Replace Activated Charcoal Filter Solenoid Valve 1 (N80)
  
• Check/Replace/Clean Injector(s)
  
• Check Fuel Pressure Regulator
  And fault 00533
  00533 - Idle Speed Regulation
  00533 - Idle Speed Regulation: Adaptation Limit (Add) Exceeded
  Possible Symptoms
  
• Bad Fuel Economy
  

Possible Causes

• Air Leak between Mass Air Flow (MAF) Sensor and Engine
  
• Injector(s) faulty
  
• Fuel Pressure Regulator faulty
  
• Throttle Body faulty
  
• Intake Air Filter dirty
  

Possible Solutions

• Perform Throttle Body Adaptation
  
• Check Hoses and Pipes to/between Components
  
• Check Intake Air Filter
  
• Check Fuel Pressure Regulator
  
• Check Exhaust Gas Recirculation (EGR) Valve
  
• Check Injector(s)
  Both are intermittent, and the system is ok half the time. He cleaned out the air filter, was fairly clean anyway.
  I hijacked the VAG COM computer ^^ and got to see some values at ~5000rpm, the water temperature read at around 80C, but the lambda values, while flicking to and fro lovely and perfect at low idle (where the car passed the test) got instantly stuck at high voltage at high rpm.
  The temp gauge was nicely at halfway then, but got significantly down again when I drove her out.
  So now I'm at:
  -thermostat
  -fuel filter
  -fuel pressure regulator
  -leaky injector (which my mechanic isn't keen to look at still, and surely I'd get some performance issues if those were involved? she runs like a rocket)
  -a bottle of dipetane to put in the tank tomorrow
  Is that solenoid valve cheap/easy to check? And what's the easiest way to check the fuel pressure regulator worthiness?
  Thanks for the suggestions
  

[chicken_eyebrow]

Only way to check the stat really is to take it out then test it in a pan of hot water see if it starts off closed then opens as the water nears boiling.

Generally if the temp gauge never gets to 90 and the air blowers never get really hot then its a sure sign the stat is sticking open.

Re. Your second code, I'd make sure there aren't any air leaks between the filter housing and the engine and maybe clean the throttle if you haven't done so already

[Grainne O']

Halfway up is as high as I've seen it, and that was today only. so thermostat to be looked into - will do

There are no obvious cracks but again it's going to have to be checked thoroughly at this stage

The throttle body is sparkling, and was recalibrated twice, for good measure, so that's likely to be ruled out now

[mac11irl]

Jaysus, but the list of things to be investigated seem to be gettin longer for you, not shorter!! Hope the source of your woes come to light soon!!

[Grainne O']

Thank God for small mercies, at least everything changed/cleaned so far has improved the idling and the smoothness of the car, so it does look like a lot of things were on the way out alright

Tbh mac, usually when that happens, people just get rid of the car (I got rid of two that way, too much hassle). But with the NCT now every year instead of 2, and every affordable car likely to fail the same emissions the same way as they get to a certain age, I reckon it's now a better bet to fix this one properly to get another 4 or 5 years out of her; she's only a 00 after all. IF I EVER GET TO FIX THE DAMN YOKE! lol. Tell you the truth, it's turning personal now. I'm going to get it through if I have to change everything a screw at a time.

I ordered the thermostat anyway 10 euro job

[mac11irl]

You'll get there. and i know what you mean about changing... catch 22 of spend lots changing to end up with the same problem you now have... or spend lots to fix the problem you do have.. horrible...

[Grainne O']

I noticed this morning how she idled absolutely perfectly when stone cold though....All the previous hardship is already worth it just for that particular outcome ^^

[Grainne O']

Got my new thermostat fitted!! Thanks Chicken eyebrow, you seemd to be dead on.

There's good news and bad news

The good news is that amazingly now my temperature needle goes up and up in a few miles only and *stays there*, and also that I have actual heat in the cabin. I hadn't realised how weak it was until now.

The bad news is that not really unsuprisingly the 00537 fault is still there, still intermittent. But we've spotted a dodgy pipe, and now wondering if it actually should be part of the big breather pipe (which, correct me if I'm wrong is the big accordion pipe coming out of the MAF). Right now there's a rubbery bit joining the engine to the big pipe with a tight clip on, LOL.

I've waited 3 hours to upload the photo off my phone but the connection is just dead tonight so that'll wait till tomorrow.

But basically should that big pipe connect directly to the engine through that little side pipe? and is this the right one and obviously do I need to buy all that?

And would that be enough to turn my oil into mayo? in passing

http://www.ebay.co.uk/itm/Air-Hose-Skoda-Octavia-96-04-1-6ltr-intake-pipe-engine-codes-AEK-AKL-AVW-BFQ-/360440422796?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item53ebec618c

Stupid questions and I kinda guess the answer to them but I'll ask anyway

As an aside I've tried that Dipetane stuff and it does make a difference, in smoothness and definitely in mpg. So I'm sticking to it for now, it's cheap enough as it is, compared to petrol. (tenner for 200 litres). It also seems to have lubricated my starter somehow? it's not screeching as often.

[Grainne O']

The offending part

[chicken_eyebrow]

I'm assuming that's some kind of crankcase breather pipe that recirculates oil vapour back into the inlet but I don't really know the 1.6 engine at all so can't be sure. You might be able to find photos of the same engine on Google to compare it to?

Does your engine have a mass air flow sensor between the air box and the throttle? Just thinking if that pipe had split then unmetered air would've been getting into the inlet after the sensor.

[Grainne O']

I'm assuming that's some kind of crankcase breather pipe that recirculates oil vapour back into the inlet but I don't really know the 1.6 engine at all so can't be sure.

That's what my mechanic said but it is now appearing that little lad is part of the big pipe. The Ebay link I gave shows a picture of the original (big) pipe, and it does look like my arrangement is just a piece of rubber clipped over a broken part? That wouldn't be good, lol

The MAF is to the right end of that pipe, and the air filter to the right of that again (bottom right of the photo, top right of the car as you stand in front of it). The throttle to the left end of the pipe obviously. This model has no MAP sensor as it turns out. (and only one Lambda sensor)

Thing is the Ebay guys are very expensive and I have had no luck googling under the words "air pipe/air hose"

Is it what you also call the breather pipe then? I haven't been able to find a pic of a mk1 to go with the words "breather pipe" (let alone my model which is the rarest), but I've found a guy who sells them cheaper

Also, if all else fails, is it the sort of pipe that I could buy off the breaker secondhand?

Does your engine have a mass air flow sensor between the air box and the throttle? Just thinking if that pipe had split then unmetered air would've been getting into the inlet after the sensor.