Help please. MOT failure on emissions.

[Graham]

My NSX just failed it's MOT today on emissions. The Lambda spec is 0.97 to 1.03 and my car was 1.072 first time and then 1.12 the second. They give them two chances. There are no warnings on the dashboard about failed sensors.
The car was off the road for 6 months in the winter and the trip to the MOT station was pretty much it's first trip out. I reckon it needs a good ragging to clear it all out inside, but now with no MOT I can't legally drive it anywhere.
I'll take the very long route on Monday to the MOT place in an effort to get the system as hot as possible but I can't think of anything else I can do.
Any ideas anyone?

[NSXGB]

Yes, book it in for the MoT and take the long route there, preferably up the motorway. Get the cats really hot and get them to check it ASAP at the station. It should be fine.

[britlude]

also give the air intake temp sensor a clean, reports that it makes a difference on NSXprime, and costs nothing!

http://www.nsxprime.com/forum/showth...smog-Read-this

[Graham]

OK, well there's a hint from Britlude's link to Prime, about the Air Intake Temp Sensor. As I've only ever worked on the nuts and bolts stuff and left all the engine stuff to Kaz, does anyone halve a photo of where this sensor can be found? On Prime there seems to be a conflict about whether it's on top of or below the intake manifold:-

"Bottom of the intake manifold, on the front bank under where the throttle cable is roughly and to the right of the EGR"
"The sensor is highly visible on top of the intake manifold, "

Also I need to remove the magnesium intake manifold cover, and the plastic fuel rail cover. Any thoughts?

I could just start taking pieces off starting at the top but I only have Sunday to do this before I go back to the garage on Monday morning. I could delay that of course but they're doing a four wheel alignment check and they said they'd shove the emissions sensor up it's exhaust at the same time.

[britlude]

here you go.... pretty straight forward, just don't drop any screws!


the sensor is on the top of the engine, front side of the inlet manifold.... just above the H of the honda logo
WP_20151212_13_15_06_Pro by jon sutherland, on Flickr

the top cover and the front injector cover off....
z2012-05-17-521800x600 by jon sutherland, on Flickr

looks like this.... probably filthy and covered in oil and debris
z2012-05-17-522800x600 by jon sutherland, on Flickr

what it should look like!
z2012-05-17-526800x600 by jon sutherland, on Flickr

[marknsx]

My Nsx has just been MOTd. Failed on emissions. Honda ran it very hot and hey presto it passed.

[Hagasan]

I'm sure it'll be far easier to run the car really hot then go straight in to the emissions test.

A few years ago I booked my car in for an MOT. I asked the garage if they would do it upon arrival at the alotted time. Of course they said yes..

When I arrived I had to wait and they finally stared about 45 mins later. Of course it failed. Now I'm running a CTSC on my car but also bear in mind that this supercharger is 50 states legal in the USA so even in California it passes the emissions test.
Based on this and even though the design is to run a little rich I fully expected it to pass.... as long as it was hot.

I said this to the mot tester although he seemed sceptical. I discussed this with the service manager and how I'd made the specific request to test the car promptly and on time...

I then took the car for a quick run up the A1M between junctions, returned, the tester hooked up and it passed!!

So as others have said... get it hot.. It might be all that's needed. If your car is standard with the cats etc and there is no engine light signalling a possible lambda sensor fault it should be fine. Just have a decent run after its hibernation....

[Nick Graves]

Lambda sensors can go off as they age and so the car could be running rich. Sooty tailpipes might be a sign...

I used to give my Prelude an Italian tune-up before the MOT, as it did use oil - early FRM bores. Always absolutely fine on the test!

[Kaz-kzukNA1]

Is your NSX first used before 01/Aug/92?

[Graham]

Hello Kaz, nice to hear from you again. Alas no, even though you were convinced that from the engine/chassis number that it's a '91, it nonetheless was registered in April '93.
Were the rules different before August '92?