Almera GTi N15 emissions

P

Paveway

Hi Folks,

I've not been around for a while. My membership of the AOC lapsed a year ago last April and I tried to renew it but I couldn't seem to get anyone to respond to me so I gave up in the end. Perhaps it got lost in my spam filter?

Anyhow, sorry to be a pain but it's question time. My N15 GTi has failed its MoT this year on just its emissions and both the garage and I are tearing our hair out trying to sort it. The car has a Powersomething manifold (XS Power?) and a K&N panel filter element (standard replacement) but is otherwise standard.

We had a new cat last year to get through and it was fine. This year everything we've tried has failed. New cat, new Lambda sensor, injector cleaner (trade only heavy duty) and emissions reducer gunk (trade only, again) and still no good. There are no fault codes registering but the cat was black when it was taken out so it's overfuelling. The ECU is apparently trying to give the minimum fuel delivery but it's still too rich.

All the garage have left to try is the air flow meter and I don't want to pay out for that if it's not going to work. That reads within spec for resistance at idle if that means anything.

If he can't sort it tomorrow, it might well end up being scrap as we can't manage without a car and the MoT runs out next Monday. We put it in on May the 1st too, so this has been ongoing since then.

Is there a common emissions problem / solution for these cars please?

Damn it, it doesn't even have a rusty tailgate and it's been 100% reliable for the last three years.

Any help greatly appreciated.

Thanks very much,

Joe.
 
errrrrrmm ive just today put mine thru MOT, it struggled on the emission too. but i had the fuel pressure @ 3.6bar (i have an adjustable fuel pressure regulator) i set it to factory 3bar and it then passed.

whats the condition of the spark plugs and ht leads?

as yours doesn't have a afpr, maybe its worth advancing the timing a touch. this will make the spark happen sooner, giving the engine a split sec longer thus to create a more fuller burn of the air/fuel mixture. its aways a good idea to give the MAF a quick clean too fella. carb cleaner from 8inches away and leave to dry.

im only chucking up ideas matey
dd
 
I've said it before and I'll repeat it again - If you have removed the precat from the manifold/downpipe then you will struggle to pass emissions.

Find a friendly MOT tester.
 
Thanks folks. I'll ask MoT man to try cleaning the air flow meter (he may already have done but didn't mention it) but I'm intrigued about the 'pre-cat'. The MoT man is within five minutes walk of here and very friendly, but also very honest. As I do work for him too, I really don't want to try anywhere else.

The manifold came with new downpipes but I was pretty sure it didn't remove anything else vital. It had the flexible section to connect onto the cat too. Where is the 'pre-cat' please?

I've still got the old cast manifold but not the downpipes as they were quite rotten (which is why I changed the lot to be honest).

Thanks again,

Joe.
 
Thanks for that. Bother, it looks like we might be up the creek then. I'll have to get my poor old Manta on the road as a daily drive which I really don't want to do (mind you, it's somewhat non-standard and makes a fair bit more power than the GTi so it won't be too bad, until it rots away...!)

Thanks again for the help.

Joe.
 
I've had my precat removed for a number of years and have never had any probs with the emissions test. Thats not a mate doing the MOT either!
 
^^Yeah me too.

You say it had a cat last year and that you've put another one on this time round, was the old one fucked? Or just a cheapo one year jobbie? Is the new one OE spec?

I have a 200 cell race cat and my GTi pisses the emmission test.
 
have to disagree with steven about the pre-cat, rowdy's car almost passed the emissions test with no cat at all!

mine also breezed the MOT recently with no precat and cams and more mods etc.

However, before it passed it also failed badly and the emissions were all over the place, the MOT tester was very worried that he hadn't got a clue what it was and could be very expensive to find out, not the lambda, not the cat etc.

I was panicking...

However, asked on here and a couple of people were certain it was the air flow meter, i took it out, gave it a quick clean with carb cleaner, and went for the re-test. Not only did it pass, the emissions were right down near the minimums, the MOT tester couldn't believe it!

So definitely definitely try that, do it yourself as well, my MOT tester was unsure that something like that could make such a difference and probably wouldn't have tried himself.

Other than that, if air filter's clean and like you say everything else has been checked, there isn't really a reason why it should fail. Fingers crossed! :)
 
Thanks again folks. The tester has tried cleaning the air flow meter (AFM) but I'm going to give it another go tomorrow on your advice. I might have a bit more time to do it thoroughly than he had.

As for the cat, he said himself he was wondering if it was something to do with it not being an original one but it when he took it out, it was very black inside and it seems that the car is running too rich. He's put another new one in this time and still no good.

He's checked the ECU and it's running the fuelling as weak as it can (64%, sorry, I'm no expert on this type of electrical gubbins). What he didn't have were the specs for the AFM above idle. I've now found these for him from the on-line Primera and Almera manuals kindly provided for me by the AOC a couple of years ago so he'll be able to have another go with those next week.

He's also asked me to try to get hold of a second hand AFM (any offers please?) to try and to disconnect the battery for an hour or so to re-set the ECU before we bring it back. Incidentally, the readings aren't that much out now either so we can't be far off.

The car's not perfect but for its age it's a pretty good one, really reliable, and I'm so loathe to scrap it just for flipping emissions - how "green" would that be!

Thanks very much again for the help. If we manage to get it sorted this time and keep it, I'll certainly re-join the Club (and that's not meant to be blackmail, it's just there's not much point in re-joining if we no longer have the car!) I'd still be a member now if my attempts to re-join when it ran out last year hadn't somehow gone astray.

Joe.
 
StevenC said:
I've said it before and I'll repeat it again - If you have removed the precat from the manifold/downpipe then you will struggle to pass emissions.

Find a friendly MOT tester.
Click to expand...

Sorry Steven but thats bollocks, if the car is running as it should then it will pass with no problems at all, like craig said Rowdys was ok with a decat, I had mine tested and was literally like .0000001 over, swapped in the cat and it passed like it was stock.



Be super careful with the MAF they are very delicate, if the MOT tester has already played with it check its not damaged, lightly spray some carb cleaner on it from quite a distance away, it wont take much to damage it...
 
And Don't use Rock Oil Karb Kleen, it leaves a horrible white powdery residue behind which is going to make things worse on a MAF.

Have you tried looking for air leaks on the inlet manifold, And adjusting up the idle settings? Pull your TPS plug off and see what happens. Adjust it all up as per the factory manual and you should have a sweet running engine. Mines been running super rich since 've had it and A MAF clean and quick idle and timing adjustment has seen it come down a lot and now runs 100 times better.
 
Hi Folks,

Well it finally passed today, just. A second hand AFM made no difference even though it was giving better voltage readings than the original one.

It turned out there were several factors including an air leak on the exhaust manifold, blow-by on the pistons causing lots of oil vapour to enter the inlet manifold and frankly, the lambda sensor is fitted in the wrong place on the XSPower manifold so it's always reading from one cylinder instead of all four.

As soon as it had passed, they gave it another try and it would have failed again, so we've been lucky.

Sadly, this means we'll keep it until early next year but then it will have to go. We can't go through this again next April. Our garage chap has been really good about the cost as he's not recorded all his time, but I'm still expecting a fair old bill from him.

I don't think I'd bother with an XS Power manifold again. It was a blighter to fit for various reasons, all the fittings have seized into it and it didn't make much (if any) difference to the power output either. All it definitely did was make a bit more noise.

Anyhow, thanks again for all the help.

Cheers,

Joe.
 
You wouldn't want the splitters, they're, er, split (seriously).

There might be a slight chance I'll be keeping it now. Our garage chap went on a seminar yesterday and mentioned the problem to someone. They think having the Lambda sensor in just one downpipe will always give poor readings (and all our emissions problems started after I fitted that manifold), so, as I kept the original cast manifold, I might get another standard downpipe and see if putting it back to original sorts it all out. If so, we'll hang on to it.

Mind you, I've got my Manta on the road now just in case...!
 
that sound like it will solve the problem, is there much smoke coming from the exhaust. i had do do a engine transplant on mine cause it wasn't going to pass the mot on the emmisions. but bear in mine piston ring were fu**ed as well as the stem seals put when i took it out i found out the big ends were going to lol just a few ideas for ya. to pass yea before i had to get the engine really really hot plus a good oil change with a new filter just scrapped through.
 
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