What setting should be used to test Import Emissions?

[Daston]

Hi guys,

Took my 1997 RX7 to an MOT today and it failed horribly on CO% during the emission test. The car is completely standard apart from a Cat back exhaust and the garage think my Cat is knackered. However with the way the rotary engine is I am not 100% sure they are testing it correctly.

We tried the first test as a UK RX7 which it failed big time. We then tried to test it on the basic Cat test and again it failed.

The HC and Lambda readings were also out but not by much and all readings were consistent.

I have gone through the paperwork and the previous years it has passed without issue.

Can someone confirm what they should be testing?

[Daston]

blueedge said:

The issue with the RX-7 is they tend to run a little rich on the fuel mixture which is going to cause the high CO readings. It's possible in previous years that a "friendly" MOT tester was used. Have you tried giving the car a really good hard drive to get the cat as hot as possible before testing?

That may very well be the case, last MOT shows it had CO of 0.1% and now it's at 3.4% during the test.

Car had been sitting on idle for a little bit before the test but it had also been sat for 40 min turned off whilst they did all the other bits. Will book it in for next saturday and give it a run up the motorway to get it toasty and see if that helps.

[Daston]

Got the retest later today, just planning the route I can take to get to the garage. It is 1 mile away from my house, so far I have around 30 miles of B roads planned out That should get it hot enough.

[Daston]

Retest done....failed again

We got the CO% down to 2.3% (pass rate is 0.200%) on idle it was 9.6% with hydrocarbons at 2250!!! I seems to be over fueling a tad.

[Daston]

Shnev91 said:

If ur car was 2 years older 3.5 would be the pass rate. Thats rotten luck.

Yep

Going back today for another attempt, this time going to try it with the airpump connected and disconnected to see if there is any difference. Failing that will be on the horn to the engine builders to see if they have any ideas.

Want to get it sorted before Japfest!!!!