Help with high carbon monoxide emissions

Max · Post by **Max** » Mon Sep 24, 2018 4:57 pm

The timing was rechecked by the garage as i was under the impression it was slightly advanced by Rich, but when they checked it seems it was actually bang on, i just had a bit of a mare setting it and got it wrong, at some point ill rotate the flywheel and mark the line clearer.

The plugs are OEM platinum NGK's i just shouldn't have trusted them to be set correctly, they're bang on now.

The idle was only hunting very slightly by around 200 rpm when trying to hold fast idle at 2000 rpm, but after the work on the FPR it seems to only hunt between 50-100 rpm now. I do need to get around to cleaning out the IACV and FITV at some point though.

I bought an ebay JDM size cat which was as far as i could tell identical to the original from the outside, the exhaust was then built by Infinity with 2.5" piping from the cat back.

Max · Post by **Max** » Mon Sep 24, 2018 6:42 pm

To be clear on the exhaust, the manifold and downpipe is standard, only the cat and catback exhaust have been changed, prior to this the cat was standard, the mid section was from a 2.0 so would have been a 2" i believe and it was hacked to death with a clamp joiner tube section (what a mess it was) the back box was a Fujitsubo which is still have and will be up for sale at some point.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Sep 25, 2018 3:11 pm

F20C and H22A5 exhausts are the same from cat back, AFAICS, so same diameter.
Sounds like you've only done good stuff, but if you have put a more free flowing exhaust set up on now, that could in itself be upsetting emissions.

Max · Post by **Max** » Tue Sep 25, 2018 5:18 pm

I think you mean F20B buddy, yep I've been quite sensible on this one, no power mods at all except for the exhaust, but i wouldn't expect any change from that especially only being .25" larger than standard diameter, id be surprised if any car experienced an emissions issue just from that, I'm pretty sure Mr Hardy has exactly the same exhaust and no issues.

Anyway we shall see, the lude is back at the garage now for an emissions test tomorrow, if it passes it will get a full MOT test and should pass with only advisories for the tyres which I'm planning to change as soon as it passes

Max · Post by **Max** » Wed Sep 26, 2018 5:34 pm

So it failed emissions again with some slightly confusing results, although it has improved so im part of the way there, for reference these were the previous results:

Fast idle
CO < 0.30%vol
0.86%vol FAIL
HC < 200ppm vol
138ppm vol PASS
Lambda: 0.970-1.030
1.023 PASS

2nd Fast idle
CO < 0.30%vol
0.80%vol FAIL
HC < 200ppm vol
95ppm vol PASS
Lambda: 0.970-1.030
1.013 PASS

Natural idle:
CO: < 0.50%vol
0.63%vol FAIL

And the new results:

Fast idle
CO < 0.30%vol
0.64%vol FAIL
HC < 200ppm vol
86ppm vol PASS
Lambda: 0.970-1.030
1.00 PASS

2nd Fast idle
CO < 0.30%vol
0.80%vol FAIL
HC < 200ppm vol
92ppm vol PASS
Lambda: 0.970-1.030
1.00 PASS

Natural idle:
CO: < 0.50%vol
0.45%vol PASS

I say confusing because the 2nd fast idle test is worse than the first, normally this is the other way around as the cat is a bit hotter on the 2nd test so works better, not sure what to make of this. Maybe its an indication that the current ebay cat is a piece of crap.

So its a big improvement on Natural idle and some improvement on the Fast idle but its still not quite there, starting to wonder if this FPR is faulty and I wish i had a way of testing the fuel pressure but i don't. The garage is adamant again that i should try a bigger cat, but the problem with that is i doubt ill find a suitable 'fatter' cat that can just bolt in, ill probably end up having to get a UK length one instead. Not sure what to do next, could try another FPR to see if it makes any difference, the local breaker probably has one. May have to call Rich and get his opinion...

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Fri Sep 28, 2018 10:32 am

Max wrote:I think you mean F20B buddy

Yep, spot on - sorry, I'd just been fanking over some S2k's on youtube earlier in the day and my head was still in a spin

FWIW my bb4 never passes a cat test either, because of the upgraded exhaust and intake - otherwise completely stock (including stock cat). It's literally just the exhaust and intake throwing it out on mine.

stinkypaul · Post by **stinkypaul** » Fri Sep 28, 2018 11:31 am

@max I have a "friendly" mot place. Have you considered asking around to find one near you?

Funnily enough at my last mot my prelude's emissions came out very similar to a 2016 1.6 mini

Post by **newkid** » Fri Sep 28, 2018 12:22 pm

newkid wrote:Good chance the cat is doing nothing or that's my experience of there cats for 5th gens.

Get a proper cat on there. Even a good used one will make all the difference

Max · Post by **Max** » Sat Oct 13, 2018 12:58 pm

So i gave in and went back to infinity exhausts, had them put a proper 400 cel high load cat on it and while there i got them to add in another resonator to bring the noise down as i wasn't happy with it.

Just been for an MOT and happy to say it has passed emissions with flying colours! The issue was 2 things, the pressure regulator and the cat itself, changing the lambda was probably a pointless endeavour... they used some different parameters for the CO this time which were tighter but in the end it didn't matter as the results were so good

Fast idle
CO < 0.20%vol
0.03%vol PASS
HC < 200ppm vol
9ppm vol PASS
Lambda: 0.970-1.030
1.09 PASS

Natural idle:
CO: < 0.30%vol
0.25%vol PASS

Next up, a set of new tyres followed by changing all the lower balljoints, not looking forward to the cost or the process of changing the ball joints especially the rears, anyone know where i can find a good guide on this?

Post by **RattyMcClelland** » Sat Oct 13, 2018 1:23 pm

Hi Max
I just had my Mot done today on my type S.
Passed. They didn't even do an emissions test. The tester said because there is no data because import so as long as it has a cat and doesn't smoke.

Yet in the pass I have failed emissions tests on the s
Depends on the tester I suppose.