# Running rich, black soot in turbo outlet and downpipe



## Thebigzeus (Dec 2, 2018)

Not sure if this will get any traction in this sub forum, but I will try. I blew the V band clamp tonight and was going over the exhaust. The inside of the turbo outlet was covered in black soot as well as the inside of the downpipe. I assume this is unburnt fuel. Would this be a by product of the tune? Is it expected? I assume without a wideband, it may be hard to tell? Looking at other turbo pictures, they aren't near as black as mine is. Any thoughts are appreciated.


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## HatchLifeRS (Oct 3, 2017)

If I had to guess it would be because of the tune. My tailpipe has some black soot as well with a tune. It could've happened without the tune, I just never paid attention before hand. However my Hyundai used to have black soot as well on an stock non-turbo engine. So personally I wouldn't be concerned about it. Although I would be curious to know why.

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## eddiefromcali (Aug 21, 2017)

What are your Fuel Trims like? Might have a boost leak and causing a rich condition. The tune will command the same fuel ratio as stock, so it shouldnt be tune related. This is likely due to a maintenance issue.


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## Thebigzeus (Dec 2, 2018)

eddiefromcali said:


> What are your Fuel Trims like? Might have a boost leak and causing a rich condition. The tune will command the same fuel ratio as stock, so it shouldnt be tune related. This is likely due to a maintenance issue.


I have boost leak tested the car into oblivion lol, only small leak is from atmospheric bypass valve and its a very small hiss, in the past had many leaks (intake manifold, throttle body). From 20-10psi on boost leak test it takes over 40 seconds which I believe is more than acceptable. I ran some diagnostics today, will check fuel trims once I am back at pc. Long term trims I suppose?


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## eddiefromcali (Aug 21, 2017)

Yeah, LTFT should be close to zero.


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## Thebigzeus (Dec 2, 2018)

eddiefromcali said:


> Yeah, LTFT should be close to zero.


Here they are:


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## Thebigzeus (Dec 2, 2018)

I guess it's good.


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## [email protected] (Nov 12, 2011)

We run a richer AFR at wide open throttle than the stock tune, which is quite lean due to the low boost. It's normal to see some soot with a tune. AFR at part throttle and idle is the same as stock though.


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## Thebigzeus (Dec 2, 2018)

So an update to this, seems lately the lftf are way off, as the engine heats they get worse... How could that be? Seems to run pretty good, am I just looking into the numbers too much? (I just put green giants in, so I am watching this on purpose) Not sure where to ask questions, nothing against Jerry, but he just sends one sentence back and an updated tune. I would like a little more.


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## Muz (Apr 15, 2018)

I've been chasing a similar rich issue, but definitely seems like a boost leak here (according to BNR) still yet to verify the exact leak though. Not an issue from changing to 42# injectors from stock. Plugs are quite black with soot/carbon. It's not a tune issue either, just really hard to find this boost leak. I've been searching but haven't found it yet. Can't 100% verify it's a boost leak until it's fixed though...


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## Thebigzeus (Dec 2, 2018)

They aren't going quite as negative with recent tune and plug updates, but it's still weird to me. Car seems to run fine... I guess it's a dont worry about it. I got rid of the NGK BKR plugs and got new AC Delco ones, seems to burn cleaner, but I dont know if that would affect fuel trims, maybe?


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## Thebigzeus (Dec 2, 2018)

Still dealing with this, its very weird as the engine heats they get more negative... What does that mean? Just as in the graph above.


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## [email protected] (Nov 12, 2011)

Check PMs


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## Muz (Apr 15, 2018)

Hey Bigzeus, any more info on this would be appreciated.
Thanks, Muz...


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