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de-cat ecu reset ?


Evil-C

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its completely standard. i'm not looking to go mad with the mods, i had a 350gt a few years back and de-cat'd it sounded a bit better and gave it a few extra horses. why would it ruin the engine? as you can tell, i'm no expert at these things :0 ..

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Fitting decats will not screw your engine, its will not cause it to run lean, all it will do is remove a slight restriction which the ECU is perfectly capable of adjusting AFRs for via lambda feedback, not sure if the map ever goes open loop on the 370 ? i suspect not, but if so its will run things on the rich side for safety anyway.

I am not convinced that decats are going to achieve anything without breathing mods and a remap anyway.

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I'm doing it mainly because i have a standard exhaust and on more than one occasion I've been doing about 75 in 4th without realising where its so quiet. i don't want it to sound like my neighbours 'maxed' corsa or do i have the funds to put a new exhaust on it so this seems like the best option at the mo. i guess we'll see.....

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I'm doing it mainly because i have a standard exhaust and on more than one occasion I've been doing about 75 in 4th without realising where its so quiet. i don't want it to sound like my neighbours 'maxed' corsa or do i have the funds to put a new exhaust on it so this seems like the best option at the mo. i guess we'll see.....

There are some backbox replacment pipes from AAM that quite a few people use instead of a full system and I think they make it a bit louder although would have to check with someone who has them to be sure.
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  • 5 months later...

Rather than starting a new thread, just thought I'd see if you had any issues in the end fitting the decats? I've picked up some Cobra de-cats on the cheap, thought it was worth a go fitting them. I assume the standard cats are just bolted on and it's a fairly straight swap to take them off, bolt new one's on?

 

Also, did you have any issues with warning lights/lambda sensors etc?

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You need O2 spacers. Fitting these is a straight 50/50 chance it may set your EML off, it may not. Many live with the EML light until they get them mapped out, by doing the pedal dance to reset the ECU.

 

I fitted HFCs before xmas and it tripped the light almost straight away, took them all apart and refitted them along with the pedal dance and so far no ECU light. 350zs have a learning ECU so any performance modifications you have will make no difference unless remapped.

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I still get the engine light with art pipes and cars been up-reved too (tried turning it off through map but always goes back on) . Been like this for 2 and a half years and car runs perfect just do peddle dance before m.o.t :)

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So with mine being Cobra de-cats rather than HFC's, could I still fit O2 spacers and have a chance that they would stop the eml light coming on? If so, how easy are they for the garafge to fit and does anyone have a link to a UK site for them? Can only find them for sale in US afer a quick google search..

 

Mine's a 370z btw, in case that makes any difference?

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Yes you can. And its literally a straight 50/50. They could come on in 1 mile, 1000 or never. They could come on once and be reset like mine were and so far so good. Its pott luck and mapping them out is the only answer

 

As for difficulty, adding spacers can be really easy and really difficult. If you're lucky they'll unscrew from the cat with a 24mm spanner, if you're unlucky they'll be well stuck in there and you'll need 02 sockets and a long breaker bar, even then they may still not come undone. When you think of the heat cycles they go through its not surprising. Best of luck!

Edited by Olly350z
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Should be fine, nearly all lambda sensors have a M18 1.5 thread.

Cheers mate! I'm sure my mates garage will know what goes where, but just out of interest, where do these go then? I take it the the lambda senors are either before or after the cats and not connected to the cats directly? Excuse the daft questions :blush:

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Should be fine, nearly all lambda sensors have a M18 1.5 thread.

Cheers mate! I'm sure my mates garage will know what goes where, but just out of interest, where do these go then? I take it the the lambda senors are either before or after the cats and not connected to the cats directly? Excuse the daft questions :blush:

 

The ones your trying to stop showing a CEL are the in cat lambdas, which show a slightly different signal to the main, they are there for two reasons, firstly to notify if the cats are overheating which means that they are failing/blocked, and secondly as a back up should the main lambdas go down.

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Should be fine, nearly all lambda sensors have a M18 1.5 thread.

Cheers mate! I'm sure my mates garage will know what goes where, but just out of interest, where do these go then? I take it the the lambda senors are either before or after the cats and not connected to the cats directly? Excuse the daft questions :blush:

 

The ones your trying to stop showing a CEL are the in cat lambdas, which show a slightly different signal to the main, they are there for two reasons, firstly to notify if the cats are overheating which means that they are failing/blocked, and secondly as a back up should the main lambdas go down.

Ah okay, I see. I assumed that the O2 spacers would attach to the system either before or after simply becuase I don't remeber seeing anywhere for them to attach to on the new de-cat pipes but looking at pics of the Cobra decats online now (mine are currently back home in my folks house) they do seems to have somewhere that the sensors would attatch to on the bend in the pipes?

http://cobrasport.com/index.php/nissan-370z-de-cats-exhaust.html

 

 

i ran HFCs without a re-map for a year with no issues. Yes the EML came on after 1k miles but the re-map @ Abbey sorted that out.

 

And yes, the zed will run lean once the decats or HFCs are on.

Does the engine running lean not cause any issues then? Loss of power/damage to the engine?

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i ran HFCs without a re-map for a year with no issues. Yes the EML came on after 1k miles but the re-map @ Abbey sorted that out.

 

And yes, the zed will run lean once the decats or HFCs are on.

 

Can you explain just how the engine runs lean with decats. and by how much, AFR etc, as air fuel is determined by incoming airflow,and lambda feedback, so anything that increases/decreases this will be compensated for by lambda feedback,

so in order for the ECU not to be able to compensate AFRs would need to be way out of range which decats alone would not do, if this was the case a lot of Z would be in a bad state.

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