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MOT emissions test
scudderfish - 23/9/10 at 06:13 AM

What RPM(s) are they done at? First MOT since doing the MS conversion tomorrow, and my car is running rich. Can't go for a blast to map it better so I thought I could at least do the bits where I'll get tested and then sort the rest once I can legally drive it.

Regards,
Dave

speedyxjs - 23/9/10 at 06:15 AM

I think its one at idle and one at fast idle but could be wrong.

bigrich - 23/9/10 at 07:10 AM

CAT test is a check at 3000rpm and at idle

NON CAT is a check just at idle

Pre august 75 (IIRC) or Q plate is just a visual check for excess smoke at idle

adithorp - 23/9/10 at 07:34 AM

Cat... idle and fast idle (2500-3000prm).
Non-Cat... idle only.

adrian

RazMan - 23/9/10 at 07:58 AM

If you can tweak the map to burn well at 2500-3000 (not too lean or it will still let unburned fuel through) and at idle you should scrape through the test [crosses fingers] Have you still got an AFR gauge?

[Edited on 23-9-10 by RazMan]

britishtrident - 23/9/10 at 08:12 AM

The fast idle test can cause problem a lot of garages do it at too high an RPM --- it should always be a bit below the max rpm the engine will run closed loop.

A few years back a well known automotive data publisher published charts with the fast idle test RPM for the older Rover 214s given as 2,850 rpm --- they go open loop above 2750 rpm as a result a lot of cars failled the fast idle test.

scudderfish - 23/9/10 at 08:17 AM

My engine is 1984 so it looks like just the idle test for me then

Thanks,
Dave

Richard Quinn - 23/9/10 at 11:31 AM

quote:
Originally posted by bigrichQ plate is just a visual check for excess smoke at idle


Noooo, not always the case. Mine's on a Q but has emissions limits on the V5.

davrus - 23/9/10 at 12:23 PM

It may have limits on the v5 but mot will only be visual test as it is on a Q + you dont need your v5 for mot so tester will not know.

DRC INDY 7 - 23/9/10 at 12:31 PM

Smoke test only on a Q

Richard Quinn - 23/9/10 at 02:23 PM

quote:
Originally posted by davrus
It may have limits on the v5 but mot will only be visual test as it is on a Q + you dont need your v5 for mot so tester will not know.

Thought that this was one of the "benefits" of the fandangled computerised MOT system. I thought it showed them all the relevant info without the need to see a V5 etc. If it's not then I'll be made up.

matt_gsxr - 23/9/10 at 04:17 PM

I understand that you can't go for a drive to map your car, but all the emissions stuff is done with the car static.

Why not lower the values in the VE table until it is running stoic. from idle through to 2000rpm? Or don't you have an AFR.

Good luck with the test. It shouldn't be too tough on a 84 engine.

Matt