Bummer NCT Fail Part 4

[tigger]

Well Good day to you all you fine MX5 drivers!

Well My car went back for a full NCT after the retest failed!
Now its failed again and for high emissions on High Revs

.3 is the pass rate and it failed .4 -.6

Now the fun bit what ive done
New oil, plugs, oil filter, cleaned the K&N Induction Kit
oh yeah the expensive part, bought a new cat and had it fitted

Failed again today!!!!
what i did after it failed, I put the standard Mazda air filter back
on and put a brand new air filter in it. i then brought it to a garage
hoping they would test the emissions and they did. It failed for the
exact same, he gave the engine a good rev as well and said the emissions
were still high at this point.

Now Ive put all the fuel stuff into the car as well including the wonder stuff
suposedly Dipetane and still failed!! oh yeah some more information during this saga, brought to a mechanic and he said it wasnt misfiring and its not burning oil or anything like that.

I dont know what else to do? any ideas from all You Mx5ers cause at this stage I think the car is doomed to fail.

[leamyj]

FFS Tigger, that's a pain in the rear.

Borrow someone elses engine for a day??

Have the ecu checked out or swapped for the test..I dunno??

John

[sonichead]

Crap bad luck Tigger mate it must be getting painful at this stage, I’ll make a few inquires and see what we can come up with.
Keep the faith.
Sonic.

[Stig]

Hi Tigger,

Wow - this is odd.........seems like you've gone to great lengths to get it past the nct .........hope you get it resolved soon.

rgds,

Ollie.

[aquarian5]

Ah f*eck Tigger whats going on....thought you felt that new cat was going to solve it !!

Did you say that you were thinking of getting a diagnostic done on it ? Any insight there?

Perhaps Steve or Frank might have some thoughts on this...bit of a bummer bud.
Sincerely hope you can solve it ONCE AND FOR ALL.....

Hope to see you at the Midlands run.

Best of luck.

[sspecdave]

Tigger

Might be worth swapping the oxygen sensor with another MK2 member as this can cause emission problem .

Mx5 parts have them but not sure which one is for your model

http://www.mx5parts.co.uk/product_info.php/products_id/497

http://www.mx5parts.co.uk/product_info.php/products_id/1342

Hope this helps
Dave.

[mx5ash]

Yeah sucks alright, i'll throw up a post on nutz and see what they say.

[tigger]

Hi ya Folks,

yeah i would have looked at the oxygen sensor alright but it passed
in range in the NCT, no probs! I heard people saying before if it fails
it fails badly for that sensor.

Yeah its starting getting me down cause, im not sure what else to look
at, i've bought some new ignition leads waiting for them to arrive.

The next thing im going to look is getting the diagnositcs done on it, apparently a tuning could fix this prob????

Thanks for all the kind words folks, i knew my fellow mx5ers would feel my pain.

Any other ideas keep them rolling, hopefully will make the run on the 10th!

[Fergus]

Oxygen Sensor.

[Steve]

I'm guessing its the CO reading if its .3? If so its most likely unburnt fuel thats causing the problem.
Start with good (!) ignition leads, make sure your new plugs are gapped correctly, PVC valve is ok, clean out your intake manifold (lots of gunk forms in there) and check your EGR is working properly. As Fergus said, no harm in checking your O2 sensor!
http://forums.dfwmiata.com/showthread.php?t=11494

Actually.. on the EGR.. I remember reading that if you move the vacuum hose on the side of the intake manifold up to the vacuum nipple on the top of the intake (then plug the first one with the same rubber bung), that its meant to make a significant difference.. must look it up again..
heres a different link on it : http://www.miata.net/garage/egr0902.html
and
http://www.miata.net/garage/manifold/index.html

Steve

[Lynott]

Just pm'd you Tigger