Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: barclay03 on 28 January 2008, 15:24:28
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mega was in for its MOT today and failed on its emissions - tester even asked if it still has is cat :lol:
i suspsected it to be out, but need advice on where to start looing, results were
Fast Idle Test
Speed 3100/min
CO (0.3) 5.68 %vol
HC (200) 370 ppm
Lambda(0.97-1.03) 0.85
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2nd Fast Idle Test
Speed 2900 /min
CO (0.3) 3.82 %vol
HC (200) 318 ppm
Lambda(0.97-1.03) 0.89
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Natural Idle
Speed 750 /min
CO (0.5) 8.71 %vol
so it failed on every account....what dyou guys think? my exhaust has been getting louder, and seems to be rattling from around the passenger side cat - but ive checked it over and the fitment is solid, with no leaks anwhere in the system?! that particular cat has previous damage to it and has been welded up also..
just wondering where to start?... spark plugs are just fitted, and it was redex and run in few weeks ago (before new plugs). new lambda perhaps?
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Yuk!
That's horrendous!
there's certainly nothing left of the cat, but if those figures are to be believed there's something else badly worng because it must be running pig rich.
First off, try reading the codes from the engine ECU and see if it is complaining about anything.
Kevin
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thanks kev, yea it seems really badly out :( doin my head in as ive had some people interested in buying it and dont want to put out too much cash!
ill have a check and see if codes flag anything up!
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Yep. Check for codes first because I think the ECU should be complaining wit the emissions that bad. If that doesn't give you any leads, I'd suspect something like the coolant temperature sensor misreading. If this is always telling the ECU that the engine is cold, it will apply lots of enrichment (used to be called the Choke control;)).
Kevin
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tried the paperclip test and noticed management doesnt come on at all :? even on normal start up... i also noticed that its in a different position than the one in the how-to video...
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tried the paperclip test and noticed management doesnt come on at all :? even on normal start up... i also noticed that its in a different position than the one in the how-to video...
pop dash off, check if bulb blown. eml should come on with ignition
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just did it... bulb and holder has been removed, replaced with a new one... management light stayed on, just getting the codes just now...
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just did it... bulb and holder has been removed, replaced with a new one... management light stayed on, just getting the codes just now...
A common sales trick to hide faults on car
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yup! coincidently in the owners manual was a print out from here with marks guide on taking instrument cluster out... so will work out if it as printed whilst previous owner had it (very well respected here for his work on cars too!).
fauls that came up...
73 Mass Air Flow Sensor Voltage Low
13 O2 Sensor 1 Open Circuit
that was on second try, on first try the coolant temp voltage code was also displayed
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sort the 13, the maf one may disappear.
As the system cant go closed loop, the emissions are all over the shop.
May, if you're lucky, just be busted wire...
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yup, thats was my plan when i got MOT results, try lambda first, will have a poke around it tomorrow, see what i can see, and judge of new one(s) is neeed or not
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coincidently in the owners manual was a print out from here with marks guide on taking instrument cluster out... so will work out if it as printed whilst previous owner had it
That'll be the giveaway!! ;D
So, is O2 sensor '13' a lambda sensor in the exhaust?
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coincidently in the owners manual was a print out from here with marks guide on taking instrument cluster out... so will work out if it as printed whilst previous owner had it
That'll be the giveaway!! ;D
So, is O2 sensor '13' a lambda sensor in the exhaust?
yea, i didnt think twice of it because guy i got it from is well respected (and just checked the printed dates, and it was 5 months before he got it, so may have been owenr before him)
im assuming O2 sensor is lambda sensor - usually known them by both names... though i could be wrong lol
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Wonder if coolant temp sensor is dodgy also as suggested by Kev?
Hope you get it sussed mate :y
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yea was thinking it might be, will see if it comes up again lol good call by kev if it is, and for the sake of a few quid (im guessing, as they usually are) ill replace it :)
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Hi
I had omissions checked recently and lambda part of readings was too high and maf was suggested to as possible cause, changed it and had readings done again and was fine, but as TB said it may be something else that is flagging that up. in my case maf was flagging lambda fault.
John
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yea was thinking it might be, will see if it comes up again lol good call by kev if it is, and for the sake of a few quid (im guessing, as they usually are) ill replace it :)
It's reporting the lambda as open circuit which does tend to suggest it has failed. However, with emissions that far out I might be inclined to think that the CTS is bad too. :-/ Wth the cat not working, I'd only expect about 2% CO if everything else is in order. Lambda could have failed as a consequence of a bad mixture (like, I suspect, the cat did).
It's a cheaper fix than the lambda sensor so I'd be inclined to give it a try. Failing that, if you've got a multimeter handy measure the resistance of the CTS both with the engine cold and hot. Easiest to look on a wiring diagram, work out the pin numbers at the ECU and test it there because it's awkward to get to the sensor. At a guess you should see a few hundred ohms when hot and over 1000 when cold but at any rate there should be a substantial difference.
Alternatively, get the live values checked on a tech 2.
Kevin
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ok, went out for a wee check under the bonnet to see what im going to attack, and noticed that the AMF didnt have its plug inserted, it was cabletied up with the air temp plug... so pluged it back in and its definetly runnin like crap... so im assuming thats nackered and need a new one? (mate has new one anyway) and go from there?
done paperclip test again and understood it a bit better, codes showing are:
73 Mass Air Flow Sensor Voltage Low
74 Mass Air Flow Sensor Voltage High
135 Telltale (Checklight) Voltage Low
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ok, went out for a wee check under the bonnet to see what im going to attack, and noticed that the AMF didnt have its plug inserted, it was cabletied up with the air temp plug... so pluged it back in and its definetly runnin like crap... so im assuming thats nackered and need a new one? (mate has new one anyway) and go from there?
done paperclip test again and understood it a bit better, codes showing are:
73 Mass Air Flow Sensor Voltage Low
74 Mass Air Flow Sensor Voltage High
135 Telltale (Checklight) Voltage Low
The MAF ones should go after a while once MAF fixed. The checklight was due to no bulb at some point (to cover MAF fault?). Don't think this code clears itself, can't remember.