Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Steveh on 21 February 2020, 17:27:21
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Struggling to pass emissions tried so far changed cat ,sensor, fresh oil ,new plugs ,air filter, blanked off air injection to manifold as nonreturn leaking cant find any vacuum leaks coolant temp sensor seems to be reading right (via chinese "My Naff Code Reader") no fault codes over my 10 days now so full retest Im at a loss what to try now first time readings were CO 0.627 Fail HC 109 pass Lambda 1.047 fail :(
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That’s very close I’d get a good injector cleaner I there get the engine hot and give it a thrashing and present it at the mot station nice and warm.
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I put a bottle of redex complete system cleanup with 1/4 tank of fuel and took it for a run it was hot for retests left it running so it didnt cool down tried mot 4 times as i did different things. Seems to be running ok plenty of power no misfires ticks over smooth.
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Have you had the timing belt changed recently? Could be a tooth out perhaps?
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Slight exhaust leak?
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I was wandering if one of the valve collets had sprung off ,dropping a valve ,as the headgasket has been done , and you described pulsing ,valves ground etc but if it's tunning ok :-X
sounds like Addy's 2 ltr problems a few weeks back ,timing is worth checking though
worth reading ...
http://www.omegaowners.com/forum/index.php?topic=145812.0 (http://www.omegaowners.com/forum/index.php?topic=145812.0)
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I did the timing all the marks were lined up but I will check it thanks. It just seems to be running to well for valve problems or timing ? would it still run one tooth out ?
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most engines will run one tooth out on the belt
there's also lots of suggestions in Addy's post ,wet thermostat etc linked above :)
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Too be honest Its always been a pain to get through emissions it had a cat before couple of mots before it was sorned so not done many miles but thought i might as well swap it as the flexi was deteriorating and the cat box had taken a hit on a speed bump by the looks of it.
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Cheers Dave I'l have a look
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have you tried holding a piece of toilet paper with long nose pliers and seeing if there is any slight exhaust blow from the manifold etc and exhaust joints
IIRC the manifold can crack too on the 4 bangers
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Hi Dave thats a good tip with the toilet paper il try that think il make myself a smoke tester to make sure ive got no vac leaks as well. Its uncanny how similar mine and Addys problems are il be checking my thermostat hope hes ok thread looks like its gone quiet.
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A smoke tester something like this https://youtu.be/fhIW-Crqz8I i mean.
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Pattern cat probably that has stopped working.
I used to suffer the same on co mixture on mine (always had good lambda though). In the end I put a 2.2 cat on with a blanking plug where the seconds lambda goes and ended up with 0.03% co.
Ecotec engines will be 0.5-0.6% co without a cat so anything around there points towards the cat not working.
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Still around.
Left car with MOT place, who got it through emissions. Never asked how :) I fitted a genuine GM thermostat, as the one fitted seemed to open early.
Have done a vacuum test, shows engine in good condition, so assuming no vac leaks. Done a fuel pressure test which was down slightly, so going to change out the fuel filter recently done for another one. Fuel pressure regulator seems to be working. When vac pipe is removed fuel pressure jumps up. No leak down when left for a while. So maybe with low pressure the fuel is not a mist but slightly droplets from injectors?
Car goes great, pulls even up steep hills and even happy to do national speed limits. Economy is also good.
As said in above reply, only other thing. Is that the cat is from a company I have used before on my vehicles, but it isn't a type approved. So might get a approved one.
Good luck with getting it sorted. If you manage to do it, please let me know. Will be worth finding out what it was.
Car is off the road for now, as some wagon reversed into passenger side front wing. So took out wheel well liner to check for hidden damage. While under there checked on wishbone bushes, as it is pulling to one side when braking. Brake system checks out ok, but wishbone bushes look ready for changing. So got poly bushes for front and normal for back ones. Read that polys give better handling, also the wishbones can be tightened up with wheels in the air. Then got to find someone closer than WIM to do geometry setup, not using manufacturers recommended ones.
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Before I ordered my NTK O2 sensor, I contacted NTK Technical Department. I gave them the VIN:, Date registered, Registration Number. Make, Model, Engine Size and Engine Code.
The O2 that was supposed to fit my 2ltr, was the wrong one. When they checked against their files, I needed the earlier one, OTA7H-3C2 (Stock code 0420) Titanium Lambda even though my car is a 1995 first registered, so can only assume it was a ealier build? The Titania Lambda, which their webcat and other sites say fits mine, is OTA7L-3C4 (0431), which is not correct. So might be worth you contacting them, to check?
NGK Technical Email address:- technical@ngk.co.uk
NGK Webcat https://www.ngkpartfinder.co.uk/cars_commercial.php?type=LAMBDA%2520SENSORS (https://www.ngkpartfinder.co.uk/cars_commercial.php?type=LAMBDA%2520SENSORS)
Hope this is of some help?
Addy
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Cheers addy glad you got yours sorted I may do the same as you take it to an mot place that also does repairs for a diagnosis the one I used just do mot and not useful for advise(I'm going to have one last session to recheck everything for leaks and valve timing etc). I got a Lexmark sensor LOSO4/T18 as im low on funds. Wonder what the difference is between those NTK ones ?
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Just use live data to check the lambda is switching about 200 - 800 mV :y
also worth checking the EGR valve is not stuck slightly open ,i've seen that before
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Thanks iansoutham thats useful to know.
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Thanks Dave it was around that I think I'l put that on my list of checks to do it was going closed loop and switching between lean/rich.
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Just use live data to check the lambda is switching about 200 - 800 mV :y
also worth checking the EGR valve is not stuck slightly open ,i've seen that before
Were those figures for a Titania sensor? Ive learnt the different way they work changing resistance opposed to Zirconia which give out a voltage. Mines Titania.
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Just use live data to check the lambda is switching about 200 - 800 mV :y
also worth checking the EGR valve is not stuck slightly open ,i've seen that before
Were those figures for a Titania sensor? Ive learnt the different way they work changing resistance opposed to Zirconia which give out a voltage. Mines Titania.
giving out voltage ,so Zirconia, but look what values your "code reader" gives you.
we can't talk about chinese clone software here at OOF ,against forum rules :y
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I'm pretty sure the 2.0 16V uses a titania sensor and from memory these give a voltage in live data of 0-5V. Can't remember which end of that range is rich and which is lean, though. :-[
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Still not got MOT had to put project on hold for a bit resuming now :) just found an exhaust leak new cat downpipes where the 2 pipes go into 1 a large leak between just welded around tested with soapy water and compressed air and found o2 sensor leaking from where the wires go in :( have been sold duff pipes and sensor? at least I found something.
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Slight exhaust leak?
. Just saying...... ::)
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Still not got MOT had to put project on hold for a bit resuming now :) just found an exhaust leak new cat downpipes where the 2 pipes go into 1 a large leak between just welded around tested with soapy water and compressed air and found o2 sensor leaking from where the wires go in :( have been sold duff pipes and sensor? at least I found something.
Are you meaning that the new NTK sensor has an air leak in it's barrel? If so that's very odd. NTK is a reputable company, part of NGK. Are you sure it's not leaking around the crush washer? Either because the crush washer is missing, the sensor is not properly tightened into the socket, or the sensor has been over tightened damaging the washer.
For the record, who supplied the downpipe and cat with the bad welding?
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https://www.walkerexhaust.com/support/tech-tips/simple-diagnostic-testing.html
Helpful bit of info and simple test if youve a cheap infared temp reader.
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.[/quote]
Are you meaning that the new NTK sensor has an air leak in it's barrel? If so that's very odd. NTK is a reputable company, part of NGK. Are you sure it's not leaking around the crush washer? Either because the crush washer is missing, the sensor is not properly tightened into the socket, or the sensor has been over tightened damaging the washer.
For the record, who supplied the downpipe and cat with the bad welding?
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Yes NTK sensor was leaking definitely from rubber grommet where wires go in. could i have knacked it with compressed air but didnt put huge amount of pressure in only sealed by hand and mole grips and a piece of tin over manifold connection. The cat was from All Car Parts (ACP) brand EEC . not got around to M.O.T. but now I dont need one? Thanks Covid 19. Its confusing because on 25 march government said " All cars, vans and motorcycles which usually would require an MOT test will be exempted from needing a test from 30 March 2020" https://www.gov.uk/government/news/vehicle-owners-to-be-granted-mot-exemption-in-battle-against-coronavirus But now they say only if MOT ran out post 30th March .
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Oh sorry Enceladus it wasnt NTK it was a Lexmark sensor leaking.
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https://www.walkerexhaust.com/support/tech-tips/simple-diagnostic-testing.html
Helpful bit of info and simple test if youve a cheap infared temp reader.
Thanks useful info .
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Are you meaning that the new NTK sensor has an air leak in it's barrel? If so that's very odd. NTK is a reputable company, part of NGK. Are you sure it's not leaking around the crush washer? Either because the crush washer is missing, the sensor is not properly tightened into the socket, or the sensor has been over tightened damaging the washer.
For the record, who supplied the downpipe and cat with the bad welding?
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Yes NTK sensor was leaking definitely from rubber grommet where wires go in. could i have knacked it with compressed air but didnt put huge amount of pressure in only sealed by hand and mole grips and a piece of tin over manifold connection. The cat was from All Car Parts (ACP) brand EEC . not got around to M.O.T. but now I dont need one? Thanks Covid 19. Its confusing because on 25 march government said " All cars, vans and motorcycles which usually would require an MOT test will be exempted from needing a test from 30 March 2020" https://www.gov.uk/government/news/vehicle-owners-to-be-granted-mot-exemption-in-battle-against-coronavirus But now they say only if MOT ran out post 30th March .
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If your car has been tested and issued with a failure sheet then it has to pass the test before it can be used no matter what date it was done :y
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Yay :) finally got around to trying for an M.O.T. and passed :y got to tax it now :( :)
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Glad you got it sorted. So it was a combination of the Lexmark sensor and exhaust leaking causing all your problems?
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Hi Addy I left the leaking? sensor on (cant tell if any exhaust gas leaks seems ok) and it passed so it was the exhaust leak. I never would have found it without taking it off using compressed air and soapy water as where it was leaking was hidden between where the two downpipes join. Got a few jobs to do on it now its worth proceeding I ordered a new radiator as it was leaking from plastic end cap and I plastic welded it ages ago.
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Are you meaning that the new NTK sensor has an air leak in it's barrel? If so that's very odd. NTK is a reputable company, part of NGK. Are you sure it's not leaking around the crush washer? Either because the crush washer is missing, the sensor is not properly tightened into the socket, or the sensor has been over tightened damaging the washer.
For the record, who supplied the downpipe and cat with the bad welding?
Yes NTK sensor was leaking definitely from rubber grommet where wires go in. could i have knacked it with compressed air but didnt put huge amount of pressure in only sealed by hand and mole grips and a piece of tin over manifold connection. The cat was from All Car Parts (ACP) brand EEC . not got around to M.O.T. but now I dont need one? Thanks Covid 19. Its confusing because on 25 march government said " All cars, vans and motorcycles which usually would require an MOT test will be exempted from needing a test from 30 March 2020" https://www.gov.uk/government/news/vehicle-owners-to-be-granted-mot-exemption-in-battle-against-coronavirus But now they say only if MOT ran out post 30th March .
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f your car has been tested and issued with a failure sheet then it has to pass the test before it can be used no matter what date it was done :y
[/quote]Makes sense, and is a good reason not to volunteer for an unnecessary test. My local test station rang me up recently inviting me for a test. I thanked her for the invitation, and declined. I appreciate they are short of custom now, and there may be a rush for tests eventually, but I will cross that bridge when I come to it. We live in strange times.
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Strange times Indeed Terry :o