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First MOT fail Fast idle lambda


Randy_Baton

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2004 DE, I've got a Cobra exhaust but i think it's stock CATs. No MAP

 

1.069 on the first and 1.072 on the second (Max 1.03.). Sounds from reading this forum thats its most likely a CAT issue. Hardly use my car at the moment I only drive once or twice a month and that's not very far. would giving it a few good runs out now help at all or is it all about giving it a good run just before the MOT so the CATs are hot. TBH its always smelled a bit at cold start up, but never failed before.

 

What are peoples recommendations for a fuel cleaner i.e. Redex... BG44k?

 

If it fails again what do i do? replace the CATS? how much should i be budgeting for that?

 

 

 

 

 

 

 

Edited by Randy_Baton
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If you're running stock cats and they're failing, there's definitely an issue there since the OEM ones are 600 cell and the aftermarket high flow cats are 200 cell and a lot of people pass with those as long as they're hot (as mentioned above).

 

Worth checking the stock cats and if there are issues, go for a set of aftermarket high flows. The original Nissan OEM Cats are insane money if purchasing new (over £1k per side). 

 

We have a set of Berk HFC in stock at the moment if you're in a rush: https://www.torqen.uk/nissan/350z/exhausts/high-flow-cats/29-350z-de-berk-technology-metallic-substrate-high-flow-cat-bt1401-hfc-met.html

 

Our own brand TORQEN ones are cheaper but we're currently all out, due a restock in the next few weeks. 

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5 hours ago, davey_83 said:

How do you use this? I've ordered some, I also ordered some bg44k but it won't get here until Monday and I'm due back a the garage Tuesday morning. I should get the Forte stuff in time for the weekend. I presume it won't have an immediate effect i.e. I can't just stick it in the tank and turn up to the garage. I'd have to put it in and go for a long drive? I should get the forte stuff on Friday so can go and visit my folks over the weekend, that usually uses a full tank of petrol.

 

I did half a tank of cheap shell fuel 🥺 when the price started spiking a few months ago. I'm nearly empty now, so can refill with the proper stuff. My question is should i fill all the way up and then put the cleaner in or would it work best with 1/2 a tank?

 

And when i have it in the tank is it best to drive normally or keep the revs high.

Edited by Randy_Baton
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What I would do is put in £20 of 99ron drive it round till the light come back on. Then put in another £20 with the the cleaner so it's a nice strong mix with minimal E10 present, drive it round at varied rpm and load till the light comes back on and then fill up as normal. 

 

Only my advice, in the past I've connected a fuel line post filter to a can of forte and was amazed at the amount of crap that came out the tailpipe of my H reg Peugeot 309 1.3 carb engine. It literally smoked out a small railway bridge as in I could see the bridge behind me. The next week went to do the same showing off to my little brother and just a few coughs of smoke came out the back, guess it worked 🤣

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So its still failing, they found a small exhaust leak but fixing that didn't help. I did 150 miles on 1/2 a tank of 99ron with one bottle of Fort up to the midlands and then the same back down south with anouther 1/2 tank and bottle of Fort and filled it up with 99 once i got back.

 

Not sure about the garage to be honest its got great google reviews but he didn't sound very convincing when i asked about what to do next. He said i could take it back and fix it myself (thanks, but you haven't told me what the problem is...) or they could take another look at it. When asked about what they'd do he said they would put it on "the computer" but weren't sure if they'd have time today. 

 

My MOT expired on 25th but the MOT fail was on the 20th, so i only have until Friday to sort something out.

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Hate to say it but should have gone with the method I proposed. In a position now whereby you don't know if a significantly stronger mix would have resolved the issue. You've also done 370 miles (on tyres close to the legal limit) when you could have done circa 40. 

 

You currently have no MOT, from the DVSA This vehicle's MOT has expired You can be fined up to £1000 for driving without a valid MOT

 

Edited by davey_83
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The garage said they spent 3 hours trying to fix it and have bunged up a few leaks etc but it's only improved slightly and is still a fail. They thinks it's the cobra back box as its after market and have advised me to put the oem one on and retest (not that I have it). The cobras only 6 years old new direct from cobra.

 

Really don't know what to do now.

 

 

There's a local custom exhaust garage who I used once before and seemed pretty sound. I'm going to take it to them. They are a normal garage with an side hussel in exhaust so they do MOTs

 

 

 

Edited by Randy_Baton
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