Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: TonyBrister on 23 August 2009, 20:15:39
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Hi, my 2.2 Omega is failing its MOT on High and I mean sky high co2 at fast idle, everything apears hife and the engine is running as sweat as possible, there are no faults showing and the emissions are fine at tickover, The breather system is clear it has had an oil and fillter change and a flush, a new cat and a new airflow meter tried but at 2500-300 rpm the co2 goes off the scale. Has anyone encountered this before?
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Yep me >:( You need to get the codes read and you'll probably find you've got P0170 as a fault. Where are you?
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I'm in Exeter Devon
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I wonder if it's a faulty lambda sensor?
Would be good to get some live data from it to see what the lambda sensors and fuel trim are doing. :-/
Kevin
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No faults are showing atall, Lambda is reading spot on.
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Do you have the figures from the emissions test print out? Can you post them up please?
Kevin
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Hi Kevin
At fast idle the co 1.28, HC 1.96 and Lambda 1.00
Tony
Also exhaust smoke is to dark grey
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Hi Tony im from newton abbot.What year is urs
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Hi, It's 2001 94000 mls. Had it since 2004
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Iv got a code reader that should read it then mate :y
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Garage say's it reads as all clear on the faults...
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Have u tryed giving it a really good blast down the motorway
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I blast up and down the motorway everyday to and from work...
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The emissions figures you have from the MOT are measured in the tailpipe after the catalytic converter. The cat can confuse diagnosis by continuing combustion of fuel that should have burnt in the engine. The high HC figure is not good. The lambda reading isn't very informative as it is after the cat.
With a diagnostic tool (such as Tech2) that can show live readings an experienced user can do a lot more than read fault codes. In particular the lambda sensor can be observed working (or not).
Do you have any misfiring? Are the crankcase breathers clear?
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There is no misfire at all tick over is 750-760. the guy at the garage says the lambda is + & - ing as it should. The breathers are clear and the fuel pressures are ok as are the vacume, obviously something is telling it to overfuel but the question is what
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OK reached the limit of my knowledge.
The usual question now is whether the MAF sensor, lambda sensor etc are genuine or pattern parts
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My 2.5 has a simular problem and I found a small leak in the exhaust at the small box under the passinger side rear seat area, when I bodged it they problem corrected its self untill the the paste blew off a couple of days later
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I dont think they have ever been changed
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OK will check out the exhaust...
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If it were overfuelling I would expect the Lambda reading to be low, TBH. Granted, it's after the cat but the cat would be flooded and not very effective if the mixture was too far out. As it is, Lambda is bang on.
What are the units of the HC reading? percent? If so, it is unbelieveably high, and this points to incomplete combustion, which doesn't tally with it running sweetly, and also being OK at idle. If it's in PPM (more usual IME) it's very low.
Other option is that the cat is knackered. Granted, it's just been replaced, but the CO is about what I'd expect from an ineffective cat. :-/
Grey smoke from the exhaust is odd as well. Real confusing set of symptoms. :-/
Would be good to get a Tech 2 on it and have a look at the live data.
Kevin
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Hmm. Actually, air leak into the exhaust upstream of the Lambdas might do it. Don't suppose it's a manifold gasket or a leak through the SAI or EGR systems?
Kevin
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Thanks a lot lads... I'm taking all your thoughts to the garage today...I will keep you posted,,
Tony
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O.K. latest update...
The car has been round to the main dealers and they can't find anything...
cylinder head off now as thoughts of valve problems but they are all seating ok...
But cylinder three isn't holding fluid so looks like a broken ring.. garage boss has very kindly said that they will do this but if it doesn't cure the problem he womt charge me for it...
watch this space......... :o
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O.K. latest update...
The car has been round to the main dealers and they can't find anything...
cylinder head off now as thoughts of valve problems but they are all seating ok...
But cylinder three isn't holding fluid so looks like a broken ring.. garage boss has very kindly said that they will do this but if it doesn't cure the problem he womt charge me for it...
watch this space......... :o
Blimey! Can't argue with that. A garage willing to take responsibility for their own diagnosis.
Fingers crossed.
Kevin
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I know it's a first for me too.
I had a new ecu fitted by a main dealer to solve a warm start problem... it turned out to be the cam sensor.
Fortunately I had purchased a warenty with the car and they paid for it even though it didn't need it (but I didn't tell them that!) :D :D
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I'm watching this very closely as i have the very same emissions problem right now....
I have new exhaust (from cat back) and new lambda sensor in position 1 and mine fails emissions on petrol and LPG, and the LPG is a mixer system not SGI.
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O.K. latest episode...
Injectors away for testing... Nothing realy wrong so having a clean...
In the mean time a hairline crack has been spoted in the exhaust manifold, this has been taken away to be brazed....
All should be back together on Wednesday so fingers crossed.
Looks like it could be air getting into the exhaust ..... :-X
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I have one of those cracks in the manifold too, i wonder if it's that...
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O.K. all done and back together....
Gues what... no change.
Where do we go now ??? :'(
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How is the flexi joint by the cat?? Mine appears a bit frayed so i am wondering if i have a leak there
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Hi I would think it is the air temp sensor, it dose not come up on a code if wearing out, ecu thinks its cold air coming in, should read between 8oms to 10oms, tells ecu to use more fuel or not, the faster the engine the more it reads it faster is colder idle is warmer. :y :y P.s i bourght a resister of e-bay now mine 17% low on emissions. £1.50p.http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170376231488&ssPageName=STRK:MEBDIX:IT :y
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What value is this resistor and where do you solder it?
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It is 0.10 so withe the orig it makes between 15-20% risistance, just connect it any way, test the risistace when connected. :y :y Oh its the first one only 2 connecson points just b4 the MAF. :y, realy works :y :y
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I have a question about this resistor enhancement, if it fools the cars ecu into thinking the outside temperature is higher than it actually is ( and it does because i tried it, live data said the outside temp was 65 degrees when it was about 20 degrees), how will that affect the car starting on a cold day???
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I may be wrong but I thought that the temperature displayed on the MID came from the sensor under the front bumper & that the air temperature used by the ECU came from the sensor after the air filter (or from the MAF on facelift cars)
I don't think there is any connection between the displayed temperature and the temperature used in the ECU calculations.
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This resistor enhancement DOES fit to the MAF, in parallel with the one thats in there...
The displayed temperature i referred to was the temp from the ecu via live data ("My Naff Code Reader")
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This resistor enhancement DOES fit to the MAF, in parallel with the one thats in there...
The displayed temperature i referred to was the temp from the ecu via live data ("My Naff Code Reader")
Oops, sorry. I should have engaged brain before going into print.
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Ha ha, no worries, back to the original question tho'
How would that affect cold starting??
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If the add on resistor merely corrects a wrong reading then I would think it shouldn't have any effect. If it leaves the ECU thinking that the air is warmer than it actually is then only the person who set up the fuel maps can tell you.
The ECU might use the coolant temperature as well as air temperature so cold starting might not be too badly effected.
My preference would be to replace any faulty sensors with new genuine ones & not try to trick the ECU by messing with its input signals.
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I have the instructions of were it go's, and it gose were i said it go's. :y
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Five weeks now driving a Kia loan car...I want my Omega back :'(
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Still no idea why the emissions are high???
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No, can't be much left to test.....
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Hi Tony, :y any further forward yet? :-?
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20th of October now and still no cure. I just don.t know what to do now.. :(
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What is the history with the cat?? as in is it a GM one??
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No it isn't. the garage have tried another patern one with exactly the same results, but experts at cat manufacturers dont think its the cat because of the very high HC..
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And there's definitely no leaks in the exhaust system?
Both lambda sensors changed?
Is your EGR blanked off?
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No leaks in exhaust and Im sure the garage have tried all that
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YIPPY I'VE GOT IT BACK........
After all that it was the CAT...
It turns out that patern part cats don't work on the 2.2 but they work on the 2.0...
The first thing the garage did when the emissions were high was to buy a patern CAT the same as the one I had fitted last year. The emissions were exactly the same..so even speaking to CAT experts they reconed it wouldn't be the cat with such high HC. Until somebody told them that the GM CAT is a two parter with a pre-cat, aha so upon searching around they found a CAT manufacturer in Nottingham that does type approved CAT's ordered one, fitted it and yep perfect emissions...
So the moral is, if you have a patern CAT fitted ask for type approved and get the emissions tested that way you can be safe.. how many people are buying CAT's that don't work ?
;) :D ;D :y
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Hooray... well done matey.
How much was the CAT out of interest and who did it come from??
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I can find out where it came from, due to all the hasle the garage let me have it at cost which was £187.81 which is a bit different to Vauxhalls £700..... :y
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I love reading about a happy ending!
Some fine information shared on this thread as well!
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I was quoted £285 trade club price for a cat for my model of car....
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Just out of interest, I have been told that LPG can burn valves out as it burns much hotter than petrol. Is there any truth in this? :-/