I’m looking for technical help or recommendations on: Emissions Testing
I’ve got an old '99 NB that I’ve already had some welding done on. I asked a mechanic to do the timing belt before I put it in for MOT, and he discovered yet more rust which needs yet more welding to fix up. As long as she goes through the MOT after that, then I will just about have a car that is worth what I paid for it, if we don’t count the cost of my tears, emotional trauma and mental scarring. I’m now wondering whether it would be a good idea to put it through an MOT to see if it fails on anything else before I spend any more money at it. Problem is it doesn’t have an MOT currently, and knowing that it is going to fail on a couple of things, I will then be faced with trying to get it back from the garage without breaking the law - cost of the MOT failure and recovery is likely to be over £100 and a load of bother.
Structurally it will be sound once the welding is done, and the suspension and brakes etc are all pretty much new, so there’s really not much else that it can fail on. So the only thing I am left wondering about is emissions, and what would be the cost if it were to fail on that. Taking a worst case scenario I imagine potentially needing a new cat. I have plenty of people trying to convince me that the cat is fine and that the emissions “shouldn’t” be a problem, but it’s not their wallet the money is coming out of, so I am ignoreing their opinions for now.
I keep seeing cats going online for £700-800, which would be a heart breaker if I had to shell out that much more again. Does anyone have any advice on what would be the most cost effective way to fix that problem if it was worst case and the cat was screwed rather than a sensor or something?
The value of a used MK2/2.5 cat has no relation to how effective it is, just that it contains lots of precious metal that is worth a lot scrap value (though not as much as a few months ago). Perfectly good replacements are a fraction of this, in fact many have removed their oe cat themselves & cashed it in before somebody else does. This leaves enough spare cash to spend on other things. But, as I said before, not quite as much as before.
Worth having a Terraclean. Cleans injectors, combustion chambers and complete exhaust system ( including the CAT) Costs about £100 and discount can be got by club members. Lowers emissions and increases performance and MPG. Best £100 I’ve ever spent on my NBFL.
Ah brilliant, thanks! I’ll defintiely do that anyway at some point, and if the emissions are poor for the MOT then I’ll do it sooner rather than later. Just found an aftermarket cat on MX5 Parts is £90 so I’ve decided to go for the extra welding and hope that’s the end of the expenditure - might just about get the old girl on the road in time for the long wet winter!
I’ve had all the usual welding done, changed the clutch, changed the LSD diff to a Torsen on my 2005 Icon. I now have a £10,000 car thats worth £2,500. Thats the joy of MX5 ownership. I’ve bought a 2012 NC as a daily to save the mileage on the NB thats now done 120,000 miles.
The cat needs to be very very hot to work on a Mazda.
Some testers will run all the electrics and rev the engine to get it really hot I have seen the emmisions drop as the temp goes up.
On one of my old Mazdas I used to rag it up a steep hill and it then went straight into the test bay for the emmisions test with the cat almost red hot.
Not many garages will let you do that.
you can legally take the car to a prescribed test, and return it home, or a garage for repair after a ‘fail’, but if its dangerous, you have to be careful.
At one of the local test stations the tester used to have an MX5 it was him that showed me the loading all the electrics and reving the engine till the emmisions dropped down.
