Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: wayneywoo on 29 April 2010, 16:24:20
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Hey all,
Can anyone give me any pointers as to why the emissions would be high other than:
Replaced O2 sensor
Replaced downpipes/Cat
Replaced exhaust manifold gasket (was ticking sound - blowing - will replace again.)
Would having the air filter removed make the CO reading higher?! I thought removing the air filter would help get more air in the engine and bring the CO reading on the emissions test machine down?
As you might've guessed, failed MOT today :'(
The test says CO < 30 . Mine was up around 60 for idle and fast idle....
Is there any way to alter the mixture or is it all totally controlled by engine management without any human input allowed?
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I would try a fuel additive (injector cleaner)
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Refitting a genuine air filter with help to reduce the HC readings. Do a paperclip test (link below) to see if there are any codes. Sometimes a faulty MAF can throw the CO readings up. Other than that you need to check the entire exhaust system for any leaks.
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Can you post all the readings from the emissions report from the MOT station? Seeing them all may give some clues as to why the CO is out.
Kevin
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mine failed on emissions took it back for re-test and he said here's your ticket wink wink see you in 12 :) :)
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I usualy give my cars a good hammering up the motorway before a mot to clean any carbon build up out :y
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I usualy give my cars a good hammering up the motorway before a mot to clean any carbon build up out :y
AKA Italian tune up ;)
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I usualy give my cars a good hammering up the motorway before a mot to clean any carbon build up out :y
AKA Italian tune up ;)
correct :y
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Thanks for all the replies guys!
Can you post all the readings from the emissions report from the MOT station? Seeing them all may give some clues as to why the CO is out.
Kevin
Kevin,
Here's the readings...
Fast Idle
2750-3250 - 2911
CO: <.30%vol
0.60%vol FAIL
HC: <200ppm vol
166ppm vol PASS
Lambda 0.970 - 1.030
1.019 PASS
2nd Fast idle test
2815rpm
CO 0.61% FAIL
HC 167ppm PASS
1.012 Lambda PASS
Natural idle
Engine speed 897rpm
CO: <0.50%vol
0.56%vol FAIL
I think from reading somewhere on the Vaux CD (can't remember it's name?) there is a modified exhaust gasket due to a leak that occurs at the front of the exhaust manifold where it joins the head. Is this true? I replaced the gasket with a normal patent part and the loud ticking went away and so thought I had cured the problem. My MPG went up slightly as well (more MPG not more consumption) which also added weight to the argument but now, a few months later, could it have re-occured?
Thanks for the help guys!
p.s. The guy I was quite friendly with and gave me the wink.wink. emissions pass ticket last year has left and now some young "by the book" guy is doing them...grumble...grumble....grumble....!
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Is it well serviced, breathers nice and clean, throttle boy clean etc?
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Is it well serviced, breathers nice and clean, throttle boy clean etc?
hmmm......not sure Mark ::)
It will occasionally stall at idle...
Am I thinking correctly from your answer that the ECU is trying to weaken the mixture but unable to?
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Is it well serviced, breathers nice and clean, throttle boy clean etc?
hmmm......not sure Mark ::)
It will occasionally stall at idle...
There is your starting point then :y
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Is it well serviced, breathers nice and clean, throttle boy clean etc?
hmmm......not sure Mark ::)
It will occasionally stall at idle...
There is your starting point then :y
Guides in the maintenance section?
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I usualy give my cars a good hammering up the motorway before a mot to clean any carbon build up out :y
AKA Italian tune up ;)
correct :y
The above worked for me as well although it was the garage that did it, they wanted to get out of replacing the cat that they had replaced the year before and was still under warranty!
I also have recently cleaned the idle control valve out as Idle was lumpy which did not help matters although the Italian tune worked without that.
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Is it well serviced, breathers nice and clean, throttle boy clean etc?
hmmm......not sure Mark ::)
It will occasionally stall at idle...
There is your starting point then :y
Guides in the maintenance section?
Yes:
Throttle body:
http://www.omegaowners.com/forum/YaBB.pl?num=1207387811
The other bits
http://www.omegaowners.com/forum/YaBB.pl?num=1194007453
Do both, its pointless just cleaning the ICV
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I've still got my original downpipes and cat up the shed. Replaced due to the flexi pipe splitting.
I noticed with the patent part that the two bolt holes on the downpipes don't line up properly and I'm curious if the original cat will make a difference. The replacement is quite a bit smaller?
But, to re-use the original cat, I need to replace the 9" or so flexi pipe. Does anyone know where this flexi pipe could be bought? I've seen on ebay but not too sure. Off the shelf from anywhere? I'm in Hemel Hempstead, HP3.
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You can buy the flexi section on eGay, you'd need a 51mm diameter and 100mm long. Just get it welded in to replace the old one. I'd do it for you as I've done a few but it's a long way to come for a bit of welding.
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You can buy the flexi section on eGay, you'd need a 51mm diameter and 100mm long. Just get it welded in to replace the old one. I'd do it for you as I've done a few but it's a long way to come for a bit of welding.
Thanks for the offer guy! I wouldn't want you to travel all that way.
Can jubilee clips not be used at either end with a section that is slightly oversized?
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UPDATE:
Removed the throttle body and gave it a good clean along with the IACV. Plenty of carbon build up.
Also cleaned the breather jet. This was completely blocked.
Just need to order the gaskets for the IACV to throttle body and throttle body to inlet.
Can't wait to put it all back together but I'm still not sure how this will affect the emissions other than maybe idle?
I've seen a few posts on the 'net and when they have complained of emissions, it's been a new cat that's fixed it. That's why I'm keen to get the original cat back on!
Has anyone else had good results regarding emissions just but cleaning the various parts and pipes? :)
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Is it well serviced, breathers nice and clean, throttle boy clean etc?
hmmm......not sure Mark ::)
It will occasionally stall at idle...
There is your starting point then :y
Guides in the maintenance section?
Yes:
Throttle body:
http://www.omegaowners.com/forum/YaBB.pl?num=1207387811
The other bits
http://www.omegaowners.com/forum/YaBB.pl?num=1194007453
Do both, its pointless just cleaning the ICV
Well, after putting it all back together, the idle is nice and smooth and all seems ok (not sure compared to before but anyway).
Will now get the emissions re-checked.
BTW....I didn't have any error codes and thought, just to check all was ok, I took off the air temp sensor plug and ran the car. Re-checked with the paperclip and now I get error code 0110 which apparently is "Air Temp Voltage High" so I can presume all was ok before.
Question, how can I clear the error codes. I did have a code before pointing to a faulty O2 sensor. That code must've cleared itself over time (having replaced the sensor!)? Did I read correctly that twenty ignition turn on's clears any error codes?
Thanks for all the valuable input guys!
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Help :'(
Just been to get the emissions checked (this time I replaced the air filter, left it out the first time)...
Fast Idle Test:
CO - 0.717 (Higher than first time?)
HC - 147
Lambda 1.015
Second Fast Idle Test:
CO - 0.518
HC - 192 (200 fail! few times went above 200!)
Lambda 1.013
Natural Idle
0.577 (.5 pass)
The testers opinion was a new cat.
Does the lambda at around 1 mean that the mixture is at the ideal (stoichometric or what ever it is) and so whats coming out the engine is fine, just the cat isn't converting enough CO?
Blast....blast.....blast!!!
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mot lambda spec is 0.97-1.03 but 1.00 is ideally where it should be.I see that you have replaced the 02 sensor but with what make ?,I have had many problems over the years with fuel parts 02 sensors and generally find genuine or ngk are the best
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mot lambda spec is 0.97-1.03 but 1.00 is ideally where it should be.I see that you have replaced the 02 sensor but with what make ?,I have had many problems over the years with fuel parts 02 sensors and generally find genuine or ngk are the best
Hey Henry,
Both the Lambda sensor and the cat/downpipes were changed just over two years ago. The lambda I got from AutoVaux and the cat/downpipes from a local motorfactors.
I've read elsewhere some guy who had a Vectra with the X20XEV engine and his CO emissions went down from around 0.7 to 0.005 with a new cat. Is it this simple (and expensive :-/)
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changed my cat last month due to high emissions
got cat from http://www.buypartsby.co.uk/catalytic-converter-buy.php
retested car emissions were perfect
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was the car really well warmed up prior to the test as I see that your second fast idle test is quite a bit better than the first
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changed my cat last month due to high emissions
got cat from http://www.buypartsby.co.uk/catalytic-converter-buy.php
retested car emissions were perfect
This *seems* the way forward...
was the car really well warmed up prior to the test as I see that your second fast idle test is quite a bit better than the first
I gave the car a good blast up the motorway before going to the testing station. Admittedly, the car sat with the engine off for a good few minutes before being tested...
I can see the CO is considerably lower on the second test but the HC are way high, higher than the first test. Would me re-fitting the air filter do this as the first test, I removed the air filter completely.