hey everyone so I’m having some issues with my mk2 1.8 nevada.
the engine light was on and threw a code for the o2 sensor, so I changed the first o2 sensor with a new one from MX5parts after I did that it threw up a code about the knock sensor, so i changed that with a new one from MX5parts and that was a headache in its self. the engine light stayed off for a day and came back on today with p0420 Catalyst System Efficiency → Below Threshold → Bank 1.
After buying the 2 sensors and its still throwing a light up im worried that i will buy a new cat and it will still have a light on and its costing a fair bit chasing this engine light so i can get it MOT’d. Is the only recourse to buy a new cat and hope it finally turns the light off?
I’d nip it along to the MOT premises and have them nox-test the car before lashing out on a new CAT tbh. I’d take it for a good thrashing first but only if you are happy the engine is actually performing as it should with no misfires or such…you don’t want to be dumping unburned fuel into the CAT. It’s pretty difficult to completely goose a CAT.
I’ve had warning lights on our NB over the years, but the gases were up to the mark.
There’s nothing worse than chasing a problem with expensive new parts to no avail.
thanks for the reply. its going for an MOT friday and I was planning to see what they say about it first before buying a new cat, I’ve given it a good thrashing after changing the knock sensor and it pulled very well no hesitation or stuttering like i had when the cat went on my old alfa so i thought I was in the clear but when driving the car today at normal road speeds the EML came back on. There is no misfires or exhaust leaks and the car performs like it should the only thing I forgot to check was if the cat itself was extremely hot as the light wasnt on after the drive
No worries.
Report back with results if you have time?
certainly will, if it is the cat I thinking of just doing a full exhaust system with a sports cat, at least I will have a genuine excuse for shelling out on a full system
Bad boy!
( Love the thinking!)
Strangely enough, I’ve just got back from MOT’ing my daughter’s car. The tester and I had our usual chat and we discussed a similar problem he had with his wife’s Skoda Fabia. The engine management system kept throwing up a number of random errors and warning lights. He changed the battery and that cured the problems, all of which were probably spurious; at least none had recurred since.
I wish it was that simple to be honest, I have put a new battery on when I changed the alternator. I’m having a niggly feeling that there is something wrong with the ECU or wiring harness as so far all I have done is chase fault codes, had a code complaining about the cam shaft position sensor a while back along with the knock sensor code but it cleared and the cam shaft sensor code never came back but the knock sensor did so I changed it and now I have the cat code! its fecking frustrating as the MOT is friday lol
KEEP CALM.
AND…
Kick the little si
HI MxVadz. Not sure if it’s relevant, but I had similar symptoms on an Astra! Code after code, all about sensors. As with yourself, changed them all (not cheap) In the end I got a guy with a proper machine to check it out, how I wish I had laid out that £50 first!! In the end and I hate to say it, but the ECU was knackered!! Now maybe yours is fine, but I would recommend getting on a proper machine to get the diagnosis?
Hopefully you’ll be fine?
regards Alan H
Thanks for the reply, I’ve been thinking it could be the ECU and even more so now as I had the car MOT’d and luckily the EML was only an advisory and the emissions were okish but I still want to get to the bottom of it of course so I will be taking it to someone I know with all the gear instead of buying a new cat and hoping it works. Another thing drawing me to the ECU is that it threw a code up today not about the cat but about the knock sensor yet again and after changing it I know its a gooden so the only thing left is the ECU/PCM.
The car failed the MOT on binding brakes so need to replace the rear calipers and do discs and pads too so I think the EML light is going to be on for another month depending on if its the ECU and how much it will cost me to replace, havent had the heart to look after pricing up the 2 calipers with pads and discs lol
Contact Andrew at Autolink in Dumfries, tell him “Robin” put you on to him.
I bought 4 exchange rebuilt calipers last year, plus 4 new discs, pads, and God knows what else. Done around 2,000 hard miles with them all, and all is well. He’d need the old calipers for exchange deal. Cheapest way I know to get the job done.
cheers mate, I’ve already got 4 new calipers waiting for me to collect tomorrow at euros with discs and pads as well. Should be a nice way to spend a Sunday if the rain holds off, had to hold back from buying all new carriers and bolts off MX5parts saying to myself I can clean them up with a wire wheel instead.
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