My model of MX-5 is: __ MX-5 Eunos NA Mk1 1.6 1990
I’m based near: __ Warrington
I’m looking for technical help or recommendations on: __ MOT
Took my mk1 mx5 for MOT and it failed on emissions on CO only, averaging 1.54%. HC and Lambda both passed easy. I’ve read that imports are tested at 3.5% CO instead of 0.30%, but the goalposts move often, so is that still true? MOT tester was adamant that that wasn’t the case.
Ran it on E5 for a week and drove it for 30 mins before I brought it to the test centre to warm it up. What else can I try to get the CO down?
I noticed what looks like carbon fouling on the spark plugs when I changed them last week. Could be related?
Have a read of this about Terraclean. I had my 2005 NB2 done with great results. About £100 (They used to give a discount to MX5 Club Members, worth asking)
Yes, TerraClean can reduce a vehicle’s emissions:
Cleaner combustion
TerraClean cleans the inside of a vehicle’s fuel system, including the combustion chambers, exhaust, catalytic converters, and lambda sensors. This ensures that the fuel entering the engine is burned effectively.
Better fuel economy
TerraClean can improve a vehicle’s fuel economy. One customer reported a 10% increase in MPG after a TerraClean service.
Faster ECU reactions
TerraClean allows the vehicle’s central processing unit (ECU) to react faster to fuel mixture changes, which can improve the engine’s efficiency.
It has been tested as an ‘MX-5 series’ but it is a ‘Eunos’ so I think this is the problem. You need one of our MOT experts to guide you as to your options.
Terraclean looks like a good option, there’s a place near me that does it from £120 but I’d wanna exhaust cheaper options first.
It’s deffo an import, short square plates, car check report says it was imported in 2001, but the V5 says “MX-5” not “Eunos” annoyingly. Is my best bet to call around MOT centres and outright ask if they’d test against the non-cat CO limit? Or is that a waste of time?
MOT guide mentions the need for a letter from the vehicle manufacture? What’s that about? Is that a formality, or do i actually need to find myself a letter to present to a tester?
Have a read of this, take it back and present the flow chart to him/her. Contact dvsa if necessary as they are very helpful and will send you a confirmation email too.
Your Tester is not doing the test correctly your Eunos Roadster should have a basic emmision test as it has no data in the UK Mot Testers Manual.
I used to take a copy of the relevent part showing the flow diagram when I had my car tested. The engine needs to be really hot as well.
Actually as the car is pre August 1992, it needs the Standard Emissions Test. Not the Basic Emissions Test. That means it is only tested on idle. Not “Fast Idle.”
This is all excellent info, thank you! I’ve had a read through of the Might5s post and docs and I’ve got my head wrapped around it now. Got some paperwork printed so I can go back in guns loaded.
Also as recommended, I’ve sent dvsa an email asking them to confirm it’s imported and eligible for non-cat test, so I can show that to the tester too.
Hopefully dvsa will reply like they did to me outlining the steps the tester should take so its all there in black and white. Not sure how the tester is going to take it though, they dont like being told how to do their job correctly but at the end of the day if you dont know this info you shouldnt be testing cars.
Armed with what you now know…I’d have it retested by them FOC. When oh when are these people bone up first instead of doing this to folk kile yourself? I put my 94 Roadster through 12 MOTs without a CAT ( !!) as my advised party trick was to put a bottle of Forte fuel cleaner in the day before and give it an Italian Tune up…which how I drove it as a rule anyhow. Failed a few time on stuff older cars do, but not on gas tests…ever. Because they knew their apples and oranges where I went.
I don’t like to be a ‘negative Nigel’, but I tried this course of action last year, my Eunos is registered as an MX-5.
The only way to get your V5 changed (and the details changed when your tester logs in to the DVSA MOT test data) is to get a letter from the car manufacturer.
Mazda UK cannot help (or couldn’t help me), as the chassis number is not a UK number.
You need Mazda Japan, but as a non-Japanese speaker I couldn’t get on with their website (international calls are not an option on my mobile contract).
Any help with navigating this particular issue would be appreciated!
I had a similar issue with a mot tester recently, tested my 1999 eunos as a 2009 mx5 as that is when it was imported. Spoke to vosa who confirmed wrong emissions test carried out and to go back to test center, they refused to retest at 1999. Now looking at taking it to a local garage who know imports
Im not sure if the tester is allowed to select the particular vehicle or it gets automatically populated for them so it would be nice to know that. Most testers wont be willing to help but its worth discussing it politely with them pre test, finding a helpful one is your biggest problem.
Hi there, My BBR MX5 failed its emissions miserably this year when I took it to a new MOT station. The guy told me to blast it up and down the bypass a few times to get it good and hot before testing it again. It sailed through
The online DVLA tax checker https://www.gov.uk/check-vehicle-tax may help. It should, for a JDM car show both the date of the first registration/use (presumably Japan in 1990) and the date of the first registration with the DVLA following its importation into the UK. The standards document states that for a non-UK car, the first registration date determines the emissions limits.
Tax checker says it’s manufactured in 1990 (doesn’t say where though) and first registered in July 2001, but doesn’t say a year it was first registered in a different country. Maybe the 11 year discrepancy will be enough to prove its an import?
From various experiences here, looks like it just boils down to the individual tester as to whether or not you can convince them to test it as an import.
I got failed on some other junk too. Once I’ve fixed everything and go to get it retested I’ll update here what my experience is, as it seems to be an ongoing problem.
Your v5 will show an approximate date of first use under the special notes section on the first page. Mine says “declared manufactured 1992.”
If you want a full report for the car, use https://carvx.jp/ it recognises the Japanese vin.
As other people have commented, the MoT tester is testing to a later standard because the system has selected a later model MX-5 as your VIN is not recognised.
Are you testing at the same MoT station as previous years? If not, go back to the one you used previously as the test system there is capable of recognising you have a pre-cat car. If you are using your regular test station, then you need the paperwork to show what spec. the test should be conducted to.
It is very unlikely that any amount of combustion chamber cleaning can get the CO emissions down to the level for the later test.
Note that the MoT emissions test is intended to check that the engine on the car complies with the emissions standard in place when the engine was built - so it might be worth asking the test station to search for the engine number, but this might be difficult as it is a personal import.
I only bought the car this July, so I don’t have a history with a more helpful tester sadly. I’ve used them for MoT on my daily Toyota iQ, but the only thing that comes out that exhaust pipe is sunshine and puppy dog kisses.
Engine number is B6 on the engine-side boss and the V5, but it’s a 1990 with a big/long nose crank so idk if it was engine swapped at some point?
