Teknologikal
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Registered: 11th May 06
Location: Cardiff
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Took my C16SE'd SRi for her MOT today and failed on the one thing I dreaded most...emissions. Looking for advice since the tester (in his own words) doesn't "...get involved with that side of things...". Needless to say I'm spewing chunks and had to leave the premises so looking at a full £50 retest, likely to be elsewhere.
The car has been running 'lumpy' for a couple of weeks now but even though I've had her checked over (only to be told she's got a good engine there)....nothing came of it. Since I drive the car I obviously know something isn't right. She idles fine sometimes, then the revs fluctuate not bad enough to stall her but enough to make her bunny hop if I'm not careful with the throttle.
Back to the MOT, quoted from the test:
Exhaust emissions Lambda reading after 2nd fast idle excessive [7.3.2b]
Exhaust emissions carbon monoxide content after 2nd fast idle excessive [7.3.2b]
Exhaust emissions carbon monoxide content at idle excessive [7.3.2c]
Any ideas what I can do to rectify this? I'm gonna check the plugs, the leads aren't leaking (as far as I know) and I'm going to clean the breather pipes. Next thing that comes to mind are the Lambda sensor itself and/or the MAF sensor. Really need help here, 3 days and she'll have to come off the road (no MOT).
[Edited on 24-04-2007 by Teknologikal]
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Dave A
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Registered: 10th Dec 03
Location: County Durham
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impossible to give a reason over the net, but a good place to start is a new set of plugs, new lambda sensor and a new cat.
then again, did it get tested for the engine thats in the car? as im sure your engine never came with a cat.....
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mattievRS
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Registered: 20th May 06
Location: Leicester
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To be honest id change the lambda sensor first,or clean the old one up,could also be down to the coolant temp sensor making the car run rich.Even the cat could be at fault!The list is endless so maybe take it to a specialist to have a look!
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Teknologikal
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Registered: 11th May 06
Location: Cardiff
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Well the engine is from an Astra 1.6i Expression but was used in the Nova GSi. I left the cat on the car and didn;t change anything bar the engine.
So I might not even need the cat?
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Teknologikal
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Registered: 11th May 06
Location: Cardiff
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quote:
Originally posted by m17tty
To be honest id change the lambda sensor first,or clean the old one up,could also be down to the coolant temp sensor making the car run rich.Even the cat could be at fault!The list is endless so maybe take it to a specialist to have a look!
How much for a new Lambda sensor? I've been quoted £50 for a diagnostic (pay if fault found, else free) but that's on Thursday IF he can fit me in 
[Edited on 24-04-2007 by Teknologikal]
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mattievRS
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Registered: 20th May 06
Location: Leicester
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look on ebay,roughly £30 i think!
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Teknologikal
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Registered: 11th May 06
Location: Cardiff
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Problem is the 3 day til expiration....and it mightn't be the Lambda sensor anyway....sigh, should have put her in earlier.
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Teknologikal
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Registered: 11th May 06
Location: Cardiff
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Had a bit of a 'mare since I first posted this thread. I have just about changed every sensor under my bonnet (Lambda, CTS, ICV, TPS) and sourced a new ECU....replaced the leads, plugs and even the coilpack. The injectors have been serviced by Lucas and were working fine yet she's still running lumpy. It's pointless changing the cat until I have the running issues sorted out.
The EML is not illuminating at all (but the bulb works) and the only error she's chucking back is error 24 (No Speed). Vauxhall stuck her on Tech2 but only told me that the VSS is wired to my aftermarket headunit (apparently one of the wires used to run a speed sensitive volume on the OEM radio) so I've removed it but no change in the way she runs. Vauxhall then told me they wouldn't isolate the fault since the engine is not the one that came with the car (Astra sourced C16SE, 1.6 8v).
I understand it may be possible to clean the VSS which is located behind the clocks but has anyone here got more detailed info about the procedure (eg. exact location of sensor, whether it would work)? My clocks all run fine it's just the engine management isn't.
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mattievRS
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Registered: 20th May 06
Location: Leicester
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Thought the VSS was located infront of the bottom crank pulley on the side of the engine(behind the plastic cowling).As far as i know its also just a magnet so it may be worth cleaning but i wouldnt expect much difference or change.
[Edited on 30-05-2007 by m17tty]
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Rob_Lee
Banned
Registered: 9th Dec 05
Location: Folkestone Drives: Nova 1.6 16v
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The c16se i had has an electronic speed sensor in which the speedo cable screwed into the top. This tells the ecu that the car is moving.
Your speedo will still work because is driven off a cable
Check in the gearbox to see if you have 3 wires coming from the speed sensor.
I dont know why this would cause emmision failure but best to get rid of faults that are there!
PS... the VSS isnt behind the clocks! 
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Rob_Lee
Banned
Registered: 9th Dec 05
Location: Folkestone Drives: Nova 1.6 16v
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Might be worth putting a couple of fuel cleaners through it and taking it for a proper hard drive before taking for next mot.
My nova when it had the C16se in always failed on emmisions... might be cos we removed the cat tho.
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Vaux Lad
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Registered: 15th Dec 04
Location: Stoke-on-Trent
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As rob said, it uses a speed sensor, when the sensor reads 0, the ecu then adjusts the idle valve. It doesn't change the idle when the car is moving, i guess because it could make the engine speed up, and car speed up as it lets more air in....
I dont see that causing a mot failure tho.
Do you have the exact figures? CO high, and lambda high means the engine is running rich.
Possibly a dodgy/non working cat.
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Teknologikal
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Registered: 11th May 06
Location: Cardiff
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I passed MOT today but want to rectify the fault with my engine, thread below.
My figures were (at first test station, no new parts at the time):
1427 HC and 0.33 CO Fast Idle
1069 HC and 0.29 CO 2nd Fast Idle
On both occasions lambda was off the scale, unreadable.
To clarify the VSS location, I am looking for a sensor mounted on the gearbox itself? Bearing in mind it's the C14SE (F13(CR?)?) gearbox that is the original that was in the car when I bought her.
http://www.corsasport.co.uk/board/viewthread.php?tid=363084
[Edited on 31-05-2007 by Teknologikal]
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