Yesterday i went to the ITV (Spanish MOT) and they rejected the NA for an emission failure…..i registered the car last year in Spain and did 2.000 kms with it since then, it is the first time in 24 years of ownership that i have problems with this. The car is from 1990 and has now 200.000 kms. It is in the garage (non Mazda) now and they said they have to “regulate” it. What do they mean by that? Is it as simple as some fine-tuning or am i looking at something else?
In Spain, a Eunos Roadster may not need a catalytic converter (CAT) fitted for the ITV test, provided it was first registered (first used) before August 1, 1995, and its specific VIN/model information is not listed in the official Spanish emissions database (which is typically the case for Japanese imports).
For such vehicles, the ITV station should perform a less strict non-catalyst emissions test:
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The limits for a non-cat test are a maximum of 3.5% CO and 1200 ppm HC at natural idle, which a well-maintained Eunos Roadster can usually pass without a catalytic converter.
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If the car’s details (VIN) are not in the ITV system’s database, the non-cat test standard must be applied.
Key Considerations for the ITV:
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Documentation is crucial: Have your documentation ready to prove the vehicle’s date of first use and that it is an imported Eunos Roadster, not a UK/EU spec Mazda MX-5. The date of first registration in Japan (found on import documents) is key.
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Inform the tester: You may need to inform the ITV tester that your car should be subject to the non-cat test standards, as some stations might mistakenly test it as a UK-spec MX-5.
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If it was registered on or after August 1, 1995: The car would likely be required to have a catalytic converter and undergo a full, stricter emissions test.
In summary, for most early Eunos Roadsters (pre-1995 imports), the catalytic converter is not a mandatory physical requirement for passing the Spanish ITV, provided the correct emissions test is applied.
The engine has 200k kms on it. Might need a top end refresh. At a minimum pull the injectors and send away for cleaning. The cat is 35 years old, probably 15 years past what it was designed to last for.
For the mot, in the uk, I needed to show them the v5 registration document which states “declared manufactured 19xx” to prove the age . You may find proof of age on your equivalent Spanish documents.
Check your permissio de circulation, make sure it has the correct year of registration, you may need to visit your local trafficooffice or the agency you used for registry to get it corrected if wrong.
Or, hopefully the ITV didn’t read your documents correctly.
Thanks all, i mailed the ITV concerning this registration and their answer is; its not the build year which defines the CO-test but the fact that it was yes or no delivered with electronic injection and katalysator so i’m F….. . Garage will pass again today.
buena suerte
Silly…..it passed the ITV…. First they adjusted the injection and added an additive; didn’t work and finaly they changed the fuel; they swapped the Repsol 98 which was in the tank for BP 98 and believe it or not it passed!!. I believe this is a surrealistic story as Repsol is a good brand too…..anyway it passed and i’m happy.
What’s to “adjust” on the injection?
No idea, as i’m not the handiest guy i had the garage to take care of it, on the invoice was; “Regular inyeccion” among other things as limpiar mariposa admision(admission cleaning) and the additives.
= clean intake throttle body (according to Google Translate)
Probably actually cleaned the MAF (Mass Air Flow) sensor, it can accumulate some dust or oil over time, so it wrongly assumed more air was passing, and ECU added more fuel to match.
Changing the petrol is always a good idea if the fuel is old, as might be the case on an infrequently used car.
Usually the Bosch flapper-type AFMs never need any attention in 1990 models. Some , people will break the silicone seal to adjust the spring tension on the door, but thats it. Cleaning the throttle body on 1990 cars opens a can of worms. The butterfly will have some paint applied quite roughly by the factory, literally using a brush.
This is for a Kia, but its basically the same
This is called pre-sludge paint (or pre-conditioning paint). Its a sacrificial layer of paint to close up the gap between the butterfly and the throttle body. Without it, the factory can’t set the idle properly. As the car is used, sooty deposits build up, and the paint wears away. At the first service, the garage resets the idle.
Years later, an owner takes a look, and sees its all black inside, and so fetches the carb cleaner from the shed, because he’s gotta clean that TB, right? Afterwards, the TB looks lovely and clean. The Benzene in the carb cleaner has stripped off what pre-sludge remains. But now you can’t set the idle properly.
But elsewhere in the throttle control, faults can develop over time.
This is a schematic for the 1990-93 1.6. The 1.8 is different.
The Air Valve is a waxstat; its basically maintenance free. It works or it doesn’t. Never heard of one faling. It helps provide a smooth idle on cold motors, and closes as the engine warms.
The ISC valve is an ECU-controlled stepper motor. A signal is sent to this to open or close, based on signals from the throttle position sensor, igniton rpm and the airflow/airflow sensors. If any of these go bad, you get a lousy idle. When you jump TEN and GND in the diagnostics port, these are taken out of the loop, which is why this has to be jumped to set base idle. AFMs can go bad; they need to be replaced. The ISC valve can get gummed up, and will need periodic cleaning. The throttle body has to be taken off, and the valve removed The securing screws are usually very tight. After cleaning, the paper gasket to the inlet manifold and the rubber gasket to the ISC valve will need replacing. Likely a garage will need to order these in. Leaks around the injectors can give poor emissions; you are drawing in unmetered air.
Clean the inlet manifold, and therefore sort of clean the injectors is a good idea, but that doesn’t mean go mad cleaning the throttle body.
Air Valve; it has a rubber gasket that can fail
ISC valve; you see how gummed up it can get
Basically, the throttle body shouldn’t be routinely “cleaned”; it doesn’t need it.
While investigating poor emissions on my car (or rather, its not passing the 1995 cat test), the injectors were over hauled. Afterwards, I had an engine that sttarted beautifully (no cranking), a slight improvement in emissions, but no bueno. The injectors had about 270k kms on them. The fix was a factory catalytic converter (used), which performed better than any of the new aftermarket cats. I think late imports struggle or are marginal on the later test (late imports don’t get the easier test), hence late UK spec cars have that extra long catalytic converter.
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Wow, thanks…..impressive writing giving a nice look at potential emmission issues.
For more info have a read of the “garage” section on Miata.net