Heavy smoke on decel

[MangoAI]

So I just got my 3071r put on, on idle and accelerating it’s not smoking at all but on decel it’s smoking like hell. It’s got a hood dump and screamer pipe facing the ground, for the hood dump I used a piece of autozone pipe, at first I thought it might’ve just been whatever coating is on the pipe but that doesn’t really make sense to only be smoking on decel. I also used some copper silicone exhaust gasket sealant on the turbo to hood dump connection so maybe that’s causing it to smoke?

Before this I had an F21 with a messed up compressor wheel and a good bit of play that smoked a tiny tiny bit on decel, this 3071r is used but it has hardly any play

It’s got a rebuilt AWM head with super tech valve seals which I heard could go bad early on so maybe it’s that?

Also the PCV valve at the valve cover broke right before I finished so it just has a hose running from where the valve would be that dumps under the driver side engine mount.

I deleted the SAI and n80 valve. For the time being just to get the car driving I have a bolt in the 2 hoses that the n80 and hardline are in between and for the SAI I put a bolt in the small lower hose coming off the back of the head and a hose plug on the bigger pipe just above the small one.

Any advice and input is appreciated

[MangoAI]

Yes I know the turbo could be leaking but I’m really hoping that it’s something else

[grayjay]

check the turbine outlet and lower crossover pipe for fresh oil to see if it is coming from turbo.
Smoke on de-acceleration does sound like valve guides and seals.

[willemml]

What colour is the smoke? Also do you mean to say your exhaust pipe comes out through the hood?

[MangoAI]

check the turbine outlet and lower crossover pipe for fresh oil to see if it is coming from turbo.
Smoke on de-acceleration does sound like valve guides and seals.

I’ll take it around the block and check tomorrow, I’d rather have to replace a turbo than valve guides, just build the head 12k miles ago


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[MangoAI]

What colour is the smoke? Also do you mean to say your exhaust pipe comes out through the hood?

I think it was white/grey but I’ll have to look tomorrow, it was night when I took it out so I didn’t get the best look at it


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[MangoAI]

Could this have something to do with the pcv system? Since before it routed to the left into the pcv valve and then into the tip causing it to be pulled out and back into the intake, now it goes left and into a hose that dumps under the car.


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[MangoAI]

https://youtube.com/shorts/icg6Ab903...vYEBE66DB7xBiP

Here’s what it looks like, the intercooler pipes right after the turbo are dry and the exhaust is dry, looks like I’m going into the engine again


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[Mike Tries]

I'm focused on what you did with your PCV system. I don't quite understand our PCV systems all that well--I know just enough about it to know not to mess with it. There's a PCV delete thread right here that popped up last week that kind of explains it, and of course, you can always look for Old Guy's posts to learn more.

If I understand it correctly, under boost, flow in that system would go from the block and cylinder head through the pressure relief valve (PRV), over to the TIP where it terminates just ahead of the inlet to the turbo. That area, just ahead of the turbo, would have a relatively low pressure under load because the turbo is very busy evacuating all the air ahead of it and pressurizing the manifold behind it. When you close the throttle plate, the turbo stops evacuating air from the TIP, and your low pressure zone is moved to the inside of the intake manifold, behind the now-closed throttle plate. There are some check valves that facilitate this, I think, but also that PRV is involved (maybe it chokes down the flow from the TIP into the manifold so that the vacuum is evacuating the block and cylinder head, and not just the area ahead of the turbo inlet). Maybe the check valves just prevent the turbo from pressurizing your brake booster and other vacuum devices. I could be 100% wrong in describing how this system works, and somebody will correct me if I'm wrong, but you might be blowing smoke out of that now-open system. You need that valve in there to do its job. In your video, it looks like the smoke is coming from where that PRV was.

The moral of the story here is that before I went tearing that engine apart, my first order of business would be to put the PCV system back in working order. It's easy, it's cheaper than the gaskets and bolts that you'd need to buy to disassemble the engine, and it seems like the proverbial smoking gun to me. If it doesn't fix the smoke, then at least you know you fixed the PCV system.

[MangoAI]

I'm focused on what you did with your PCV system. I don't quite understand our PCV systems all that well--I know just enough about it to know not to mess with it. There's a PCV delete thread right here that popped up last week that kind of explains it, and of course, you can always look for Old Guy's posts to learn more.

If I understand it correctly, under boost, flow in that system would go from the block and cylinder head through the pressure relief valve (PRV), over to the TIP where it terminates just ahead of the inlet to the turbo. That area, just ahead of the turbo, would have a relatively low pressure under load because the turbo is very busy evacuating all the air ahead of it and pressurizing the manifold behind it. When you close the throttle plate, the turbo stops evacuating air from the TIP, and your low pressure zone is moved to the inside of the intake manifold, behind the now-closed throttle plate. There are some check valves that facilitate this, I think, but also that PRV is involved (maybe it chokes down the flow from the TIP into the manifold so that the vacuum is evacuating the block and cylinder head, and not just the area ahead of the turbo inlet). Maybe the check valves just prevent the turbo from pressurizing your brake booster and other vacuum devices. I could be 100% wrong in describing how this system works, and somebody will correct me if I'm wrong, but you might be blowing smoke out of that now-open system. You need that valve in there to do its job. In your video, it looks like the smoke is coming from where that PRV was.

The moral of the story here is that before I went tearing that engine apart, my first order of business would be to put the PCV system back in working order. It's easy, it's cheaper than the gaskets and bolts that you'd need to buy to disassemble the engine, and it seems like the proverbial smoking gun to me. If it doesn't fix the smoke, then at least you know you fixed the PCV system.

Only thing is it’s not coming out where the pcv valve is. It’s got a hood dump so it’s coming directly
Out of the exhaust


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[Mike Tries]

I'd still start with the PCV. You know it's not functioning the way it's supposed to function--anything you do to diagnose this problem will have to account for how your PCV system changes will influence your data.

[willemml]

I think Mike is right, you should try putting the PCV system back in as it should be, rule it out. Its also quite an easy step (relative to most of the other options).

[MangoAI]

That’s what I’d like to try, but I don’t have a bung to connect it to the intakepipe, it’s just a 4”-3” silicone reducer that goes into my maf

What would my install options be with a setup like this?

I do have a catch can I can install if that’d help?


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