Mrs Opti's RX-8 fails it's MOT.

[Field Marshal Dr. Opti]

I know this isn't Omega related, but I  wondered if anyone could shine a light on this.

The car has only covered 9,500 miles and is just four years old.

It failed on the emissions test.


Fast idle speed............FAIL

CO level.......O.20%.....PASS

HC level......20ppm.......PASS

Lambda......1.12..........FAIL........................Should be between O.97.....1.03.


Any idea what caused it to fail, chaps?

[tunnie]

Sticking o2 Lambda sensor? Can you get live data reader on it?

[Lazydocker]

Why hasn't the fast idle speed passed? surely they should be holding the fast idle between the assigned range

Did you give it an Italian Tune up on the way there?

I'd be very surprised if it's a dodgy sensor... Could be a slight leak in the exhaust system

But my biggest issue with those results is that the idle should have been held in the correct range

[Field Marshal Dr. Opti]

Why hasn't the fast idle speed passed? surely they should be holding the fast idle between the assigned range

Did you give it an Italian Tune up on the way there?

I'd be very surprised if it's a dodgy sensor... Could be a slight leak in the exhaust system

But my biggest issue with those results is that the idle should have been held in the correct range

Thanks Tunnie and LD.

LD. according to the printout there is no speed range for the fast idle test. It simply says FAIL.

I tried my best to give it an "Italian tune up" on the way......but the traffic was heavy.

I don't think the exhaust is leaking. Nothing was mentioned by the tester.

[Manual Elite V6]

Why hasn't the fast idle speed passed? surely they should be holding the fast idle between the assigned range

Did you give it an Italian Tune up on the way there?

I'd be very surprised if it's a dodgy sensor... Could be a slight leak in the exhaust system

But my biggest issue with those results is that the idle should have been held in the correct range

Thanks Tunnie and LD.

LD. according to the printout there is no speed range for the fast idle test. It simply says FAIL.

I tried my best to give it an "Italian tune up" on the way......but the traffic was heavy.

I don't think the exhaust is leaking. Nothing was mentioned by the tester.

The fast idle speed for MOT emissions test is between 2500 and 3000rpm.

[Kevin Wood]

How does the emissions test kit check the RPM? Because if it''s from an ignition lead (or even exhaust note) it might get confused by the fact it's a rotary. Maybe it was bypassed for that reason?

Does look to me like air getting into the exhaust (or tester probe!) to me. I would expect these to be harder on Lambda sensors due to the oil consumption, though. That might make the italian tune up more important.

[Andy B]

How does the emissions test kit check the RPM? Because if it''s from an ignition lead (or even exhaust note) it might get confused by the fact it's a rotary. Maybe it was bypassed for that reason? .....

not sure how it works, but on one MOT, the tester clipped his box of electrickery across the battery of SWMBO's Smart - battery at front, engine at the the back, but as that means removing the bucket under the 'bonnet' on ther tests he hasn't. The test gear does need to know how many cylinders there are though, otherwise it gets confuddled

[tunnie]

Some info here Opti http://www.pistonheads.com/gassing/topic.asp?f=8&h=&t=233122

Other searches point suggest to check plugs, apparently there are 2 per chamber on these? Apparently its not that noticeable for one to fail, but will drive as normal.

[Manual Elite V6]

How does the emissions test kit check the RPM? Because if it''s from an ignition lead (or even exhaust note) it might get confused by the fact it's a rotary. Maybe it was bypassed for that reason?
Does look to me like air getting into the exhaust (or tester probe!) to me. I would expect these to be harder on Lambda sensors due to the oil consumption, though. That might make the italian tune up more important.

If bypassed it would say not checked on the printout, I think the best bet would be to read the live data first as has been suggested already.

[Field Marshal Dr. Opti]

Why hasn't the fast idle speed passed? surely they should be holding the fast idle between the assigned range

Did you give it an Italian Tune up on the way there?

I'd be very surprised if it's a dodgy sensor... Could be a slight leak in the exhaust system

But my biggest issue with those results is that the idle should have been held in the correct range

Thanks Tunnie and LD.

LD. according to the printout there is no speed range for the fast idle test. It simply says FAIL.

I tried my best to give it an "Italian tune up" on the way......but the traffic was heavy.

I don't think the exhaust is leaking. Nothing was mentioned by the tester.

The fast idle speed for MOT emissions test is between 2500 and 3000rpm.

In full...... Fast idle test......FAIL
..............Engine speed not checked 2400 2600
..............CO level...O.20%  PASS
..............HC level...20ppm  PASS
.............LAMbda.....1.12 ...FAIL

[Field Marshal Dr. Opti]

Some info here Opti http://www.pistonheads.com/gassing/topic.asp?f=8&h=&t=233122

Other searches point suggest to check plugs, apparently there are 2 per chamber on these? Apparently its not that noticeable for one to fail, but will drive as normal.

Thanks, Mr Tunnie. That makes interesting reading. I'm hoping there is not a problem with the cat.

Yes.....two plugs per rotor. One leading .....one trailing. All four plugs cost  around £200 from Mazda or about £70 from Ebay. They need renewing every 36,000 miles and are a piece of piss to change. Simply remove the passenger side front wheel to access them.  

[Kevin Wood]

Cat looks OK, because, even though the Lambda is out, it's still within the emissions limits.

[Manual Elite V6]

Given that the rest of the emissions are fine it looks like air is getting into the exhaust further back as already suggested, check the exhaust for any little black marks to suggest a very slight blow, it doesn't take a large hole for air to get in.

[Taxi_Driver]

I would say the fast idle failed because tester was too lazy to connect the sensor up. I've had that fail before and still get a pass ;-)

[tunnie]

Some info here Opti http://www.pistonheads.com/gassing/topic.asp?f=8&h=&t=233122

Other searches point suggest to check plugs, apparently there are 2 per chamber on these? Apparently its not that noticeable for one to fail, but will drive as normal.

Thanks, Mr Tunnie. That makes interesting reading. I'm hoping there is not a problem with the cat.

Yes.....two plugs per rotor. One leading .....one trailing. All four plugs cost  around £200 from Mazda or about £70 from Ebay. They need renewing every 36,000 miles and are a piece of piss to change. Simply remove the passenger side front wheel to access them.

Explains why these are cheap as chips on trader, that combined with oil use, garage costs must be huge. Good to DIY though