Need help,strange emmisions test...!

**A80Avant** · 8 February 2007, 14:29

noone??

anyway,went for the second test today,same results.On 2500rpm the HC levels reduce to 0076ppm while the CO levels become 0.86%.On idle though i still get 220ppm HC.

Could this be a valve problem,meaning that the cam shafts are not pusshing some of the valves correctly?or is it easier a cylinder head crack problem?I mean i have seen worse cracks than mine and still the heads seem to work ok and have no problems on the emmissins tests!!!

***Greg_S*** · 8 February 2007, 15:38

Could there be oil getting into the exhaust?

**S2central.net** · 8 February 2007, 15:48

Or a faulty PCV system just as likely - with excessive blowby gasses getting ingested and not burnt fully at idle.

Quickest way to test the PCV element is let it vent to atmos and test again.

**A80Avant** · 8 February 2007, 19:43

PCV i also new,changed before 4000Kms...

**A80Avant** · 8 February 2007, 20:33

i was told that due to the hydraulic tappets,the valves cannot be retuned in case this is a valve problem not reaching the piston during the movement thus it gets HC on the head and hence the high HC on the emmisions test.Is this true?are the valves on the 20V engines self tuned?If so does this mean that the head has a bigger problem than i excpected?

**A80Avant** · 8 February 2007, 20:37

where could the oil be coming from?the thing is that i do see some oil residue along side of the oil pan but nothing serious,i have no puddle when i park the car.I also seem to have some gear oil as well,same thing,nothing serious...everything just under the car

**philS2** · 8 February 2007, 21:30

the max for our MOT is 1200ppm for HC so yours seems fine.mine was about 186.

**A80Avant** · 9 February 2007, 14:29

are you sure about this figure???it seems too high!

**tris70uk** · 10 February 2007, 18:32

I believe the limit on cat cars in the uk is 200.

but that high and something isn't quite right anyway.

As the others say, are you losing oil?

The figures look ok except for the hc but maybe the turbo is leaking a bit of oil into the exhaust?

Any blue ish smoke?

Jon

**dub007** · 10 February 2007, 18:50

At idle, that sucks. Well you know you have a crack, which is a very possible source. The lifters shouldn’t cause that much of an issue. With them it either minor or your destroying parts. O2 sensors are normally a large fault. Keep in mind having a high HC rating can mean a lot of things, mostly your burning some type of fluid. A lot of times it just fuel excess. You could have slow reacting sensors. The catalyst could be bad as well. If you’re concerned about it mechanically you need to do a leak down test. If you hook up the coolant pressure tester at the same time and then run the pressure up on the leak down tester. You can see on the both gauges what’s going on as well as feeling out the dipstick tube and listening in the head threw the oil cap. This will let you know if air is getting by rings, valves or gaskets. Also get the special spray required to clean of the air flow sensor, the K&N probably dirtied that up if it wasn’t already. BTW, are your lifters making excess noise or giving you any other signs that they may be bad?

**A80Avant** · 11 February 2007, 18:07

thanks for the answers guys,here is a little more input...

I have no blue smoke and im burning no oil.Actually after the last large service i had,my oil levels are even more slowly coming down,and evertyhing seems to be working a lot better.I did have the main gasket changed,but im not burning any oil.Here is another thing though,...although im not burning any of it(and i have no blue smoke either),i do have some oil residues underneath the car at the oil pan...The oil pan is not tampered with,so im thinking that it may be from the gasket or some sensor of some sort.But the funny thing is that this residue is so small,i leave no put of oil on the floor,nor do i need to add oil in the engine.

dub007: what do you mean by'destroying parts'?O2 sensor is ok since it is new,and also the reading gave out a figure that supports it.As for fuel,i can say that Greek fuel companies tend to mix unleaded with all sorts of stuff,making them improper for our cars,but what can i say?
if i buy one of these injector cleaners or those fuel octane boosters,would that make any difference?would it clean any residues?

Air flow sensor was checked today and it is clean.However something else happened today...After i replaced the OEM air filter,and MAF is clean,the idle kept jumping up and down everytime i threw it into neutral,like when the ISV valve is dirty or damaged.It didnt do that when i used the K/N filter,and i must say that everytime that unstable idle came up,the consumption always rose,and excess fuel was burning.I refitted the K/N filter which i cleaned and removed all excess oil(there wasnt any anyway),cleaned the ISV once again,and im heading towards the way of replacing my cats.

the thing is that i dont know whether the oil that is slowly coming out of somewhere and finding its way on the oil pan,is also going somewhere where it is also burning...

Finally what interested me is that when we took the spark plugs out to check the compression,they where black,and oily.(nothing much,just a very small residue as well)does that mean something?

**A80Avant** · 11 February 2007, 18:09

also during the last service,the turbo was not tampered with,and also i see no oil residues in that area

**A80Avant** · 23 February 2007, 14:50

just bringing this up a bit...

after doing some reading in SJM site,i realized that i must be getting a righ mixture on idle as i cannot find any other reason for my high carbonhydrates and carbon monoxide.It seems that my lambda probe being 0.979 is showing a rich mixture at idle.Although it doesnt correct itself on 2500rpm,the carbonhydrates reduce at that level.

Im having my cats replaced with new ones,and also bought me a small samco vacuum hose to replace all oem hoses as im thinking of maybe having some kind of small ruptures somewhere,which although confuses the ECU into reading more air than normal,it doesnt appear on the diagnostic so that i can do a search.I will also go for a boost leak test soon so that i can listen to any changes.im hoping for the solution of the problem here,cause im thinking that the cylinder head cracks must have been there long before i bought the car,as for a year and a half that i own it,i havent done anything radical to it in driving to imply that i caused the cracks or augmented them,and a year ago the exhaust fumes read perfect!!

any other help or suggestions are welcome!

Finally i wanted to ask those who know more about this.I dont know much about the ECU programs,but is it possible to say that since the program (mtm) is made to work for an engine water temperature of 100degrees(as the OEM sensor part says),and i have replaced that with a sensor that makes the engine work in 10 degrees less and not allowing the engine to reach the temps that the program would want,could we say that this is a reason for the rich mixture at idle speed,or in general?If this is true,is it needed to be remapped taking into account the new temps?Or am i talking nonsense???

cheers
Vasilis

Need help,strange emmisions test...!

Need help,strange emmisions test...!

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