In Denial - Catalytic Converter Problem

In Denial - Catalytic Converter Problem

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Discussion

MazdaSue

Original Poster:

29 posts

64 months

Sunday 21st July 2019
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Hi Guys

I have an MX-5 Venture hard-top 2012 - which has been running like a dream until....

...after being driven from a nearby town - engine sounded loud and rough passenger-side (left) when revvng and hissing noise from the rear - by the time I reached my place a couple of miles further it was chugging along at 20 mph. It drove OK for the roadside recovery guy for a while but then happened again - plus the amber engine light came on. At first he thought it was the exhaust but he said it was blowing fine ... took it to the closest garage at 20 mph and they diagnosed that the catalytic converter was a right off.

So.. double whammy.. the spare part is 650 GBP (over 800 USD) and second it is currently not available from Japan.

...but the car has a full Mazda service (last done in November 2018) and in the MOT emision test a couple of months ago the HC was 19 ppm (pass rate is 200).

I have just filled it up with super unleaded - 100% certain the right fuel - it states it on the receipt. I thought at first he cap might be crooked but the garage says it was fine.


Any ideas why this could have happened?

Munter

31,326 posts

248 months

Sunday 21st July 2019
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There are cheaper non standard options on Mx5 parts.

MazdaSue

Original Poster:

29 posts

64 months

Sunday 21st July 2019
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Cool - I'll let the garage know - feel a bit guilty at dumping this problem on their doorstep

anonymous-user

61 months

Sunday 21st July 2019
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You could also try Autolink UK, they may have a decent used one a lot cheaper.

MazdaSue

Original Poster:

29 posts

64 months

Sunday 21st July 2019
quotequote all
Thanks - Yeh, I was going to suggest that they track down a used one until the cause is figured out. They still cost a bit but the materials will be the same.

The engine has been getting quite hot lately - it has only done 40 K so the sparkplugs were not replaced at the last service just checked. Mazda recommends they are changed at the 5 year service - perhaps this could have sparked off (scuse pun) the problem? I read that if they are not firing properly the fuel is not burned and remains sitting on top of the cat and this causes it to overheat and eventually disintegrate.

MazdaSue

Original Poster:

29 posts

64 months

Saturday 3rd August 2019
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so... my 2012 MX5 2.0 is back with its new catalytic converter AND the same fault

Seems it was not the catalytic converter after all

Any ideas? overheating engine - amber engine warning light - not revving at high speeds - loud engine left-hand side - occasional strange whishing noise. It drove OK at low speeds when I first got it back (although the exhaust has a new gurgling sound) but as soon as you go up the speedometer - hissy fit.

Spark plugs maybe? Could it be a problem with the fuel - I filled up just before it started but 100% sure I used super unleaded.

Any Mazda mechanics near Frome, Somerset? Mazda garages seem to be a rare species round here.

drgoatboy

1,713 posts

214 months

Saturday 3rd August 2019
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MazdaSue said:
so... my 2012 MX5 2.0 is back with its new catalytic converter AND the same fault

Seems it was not the catalytic converter after all

Any ideas? overheating engine - amber engine warning light - not revving at high speeds - loud engine left-hand side - occasional strange whishing noise. It drove OK at low speeds when I first got it back (although the exhaust has a new gurgling sound) but as soon as you go up the speedometer - hissy fit.

Spark plugs maybe? Could it be a problem with the fuel - I filled up just before it started but 100% sure I used super unleaded.

Any Mazda mechanics near Frome, Somerset? Mazda garages seem to be a rare species round here.
Really need to get the fault codes read and see what they say. Could be a load of things. The 2.0 is generally pretty reliable so hopefully it's just a duff sensor or something. Very much doubt it's the spark plugs.

Not sure if the water pump is belt driven but could it be a bad belt so water pump is not working hence overheating? (Complete guess)

MazdaSue

Original Poster:

29 posts

64 months

Saturday 3rd August 2019
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Thanks, yeh, I need those codes read I guess - it starts OK so that probably eliminates quite a few things but it seems quite a complex car and its just a load of speculation otherwise but it has been reliable as hell up until now.

There was a bit of a heatwave on the day it started - I had the top down but the air-con fan was on without the light being lit - never noticed that before but suppose that didn't help - thought it only worked if you pressed it and the light was lit.

I will figure out how to get it to the nearest Mazda garage for the code reading somehow - even if I have to push it smile


gforceg

3,524 posts

186 months

Sunday 4th August 2019
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Hi, maybe check the condition of the engine air filter. I think it's on the left (nearside) of the engine bay in the NC.
If it's badly clogged or even falling apart if might cause some of the things you describe.

MazdaSue

Original Poster:

29 posts

64 months

Sunday 4th August 2019
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Hi, thanks - I will definitely do that - probably would be wise to eliminate all the less expensive causes first - it is difficult when you are in a situation where you do not know what the problem is - risk local garage or an expensive haul to closest Mazda dealer. So probably wise to check all the obvious stuff first before the expensive haul/repair. Thanks, that sounds like a possibility smile

anonymous-user

61 months

Monday 5th August 2019
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If its overheated then an exhaust gas in coolant test might be wise before you start replacing other expensive parts, at best it would at least rule out a major problem like the head gasket or a warped head etc... Any decent garage should be able to do that test easily and cheaply.

MazdaSue

Original Poster:

29 posts

64 months

Monday 5th August 2019
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Thanks, I have got it booked into another local garage on Friday - so I will let them know about that - they said they would check all the obvious things first and then help me get it to a Mazda garage if all else fails - I'm dying to find out what it is smile

gforceg

3,524 posts

186 months

Thursday 15th August 2019
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Any update on this OP? It'd be good to know what they found out.
Ta.

griffdude

1,838 posts

255 months

Thursday 15th August 2019
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M-tech in Westbury are pretty clued up on MX5s if that’s any help.

MazdaSue

Original Poster:

29 posts

64 months

Thursday 15th August 2019
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Hi, thanks for asking - after taking it for a run, the local garage wasn't sure what it was but was pretty confident that it would make it to the Mazda dealer 17 miles away in Bath without any further damage - anyway I chugged it down there the other day. The cat is OK but not fitted properly so they are going to take it apart and put it back together again next week. They said the engine warning light was for the blowback on the exhaust - the engine still sounds loud and awful on the passenger side with no power - just like before the cat was fitted but there is now an occasional moo from the exhaust. The guy in the Mazda garage was certain there was nothing major wrong with the engine though and said it was OK to drive - he thought that once the cat was fitted properly it might be OK but he couldn't say for certain.

MazdaSue

Original Poster:

29 posts

64 months

Thursday 15th August 2019
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M-tech in Westbury - cool I'll make a note of that - a lot closer than Bath and I plan to hold on to the car for a while smile


Planet Claire

3,349 posts

216 months

Thursday 15th August 2019
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It might be worth you posting on the MX5 Owners Club forum too.

MazdaSue

Original Poster:

29 posts

64 months

Thursday 15th August 2019
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Thanks - I will sign up smile

MazdaSue

Original Poster:

29 posts

64 months

Friday 22nd November 2019
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Hi guys - sorry to resurrect this post but I just wanted to thank you for your help.

My MX5 was only fixed properly a couple of weeks ago after taking it to M-tech as suggested by you guys - had I not done that I am pretty certain I would have still have had problems and spent piles more cash on it.

Now the engine sounds beautiful and no engine warning lights - so a big thanks to all the people that responded to this post.

drgoatboy

1,713 posts

214 months

Friday 22nd November 2019
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Glad you got it sorted - what was wrong with it?

Edited by drgoatboy on Saturday 23 November 04:32