Boost bleed/purge line

[OffTheWall503]

I just did the same thing as [MENTION=4567]Ryephile[/MENTION] on my 2016. Pretty straight forward. Look at the "T" fitting come off the intake tube.

Disconnect the fitting and remove hose at that end, then follow the hose to the plastic tube below. Remove that end and take hose out.

Cap the "T" at the end that you removed the top connector of the hose from. Also cap the other end down below, be sure to use a worm clamp because it's pressurized.

The hose removed

And the part number of said hose (for those with 2016's)

 

[jayrod1980]

Ryephile, I went ahead and bought that vacuum plug kit from my local O'Reilly auto parts and capped off and removed that boost line.

Wow, what a difference! The car runs smoother, oddly quieter, and more responsive. After 50 miles I have yet to throw a code. I've yet to do real testing, but it seems I'm running higher vacuum pressure at 75-80mph in 6th than I was previously, which makes the drone less and increases mileage slightly. Much of this is likely placebo but I definitely feel the throttle response is quicker and smoother during partial throttle acceleration. I will continue to monitor. What again is the danger of capping this? Crank vapors not vented?

As an aside, what does Ryephile mean? Do you enjoy Rye whiskey?


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[skidro87]

I'll chime in since I think I might be the only 2015 doing this. The car was pulling less vacuum in the beginning but I believe the OAR settled back down again and my vacuum is about the same so is boost.
Before with the heat blasting it would smell almost like coolant in the car but now that smell is gone?
Actual boost seems less twitchy and I can definitely throttle it better and my boost doesn't taper off as much.

Weird problem of mine though, I somehow twisted one of the heat shrink hoses and now it's at a different angle so I can't even reinstall it without bending the hose

 

[OffTheWall503]

Just checking in after a week of driving on this mod. So far so good. Runs very well and boost is smooth!

[MENTION=4567]Ryephile[/MENTION] - did you notice an increase in max boost pressure after doing this mod? I never checked before the mod but when I logged today I noticed a max boost pressure of 23.67 lbs.

 

[Ryephile]

[MENTION=2065]jayrod1980[/MENTION] and [MENTION=4498]OffTheWall503[/MENTION], Glad you guys are trying it out and are feeling an improvement. The only code the car would post doesn't appear to be a utilized monitor, so it shouldn't have a CEL potential like it does with the Abarth setup. The placebo effect is probably minimal, as the couple CFM of compressor pressure ratio improvement is a tangible metric. Also we're not talking about crank vapors, but charcoal canister vapors. There's no danger as the main vent line is still hooked up to the throttle body, which is the primary vent. The engineering reason for the OEM design is to satisfy a fairly arbitrary theoretical situation that's simply not realistic, as I gave in my operational example a few posts ago in this thread.

[MENTION=4706]skidro87[/MENTION], the coolant smell has nothing to do with this evap line and hopefully was a random coincidence. Any chance you can take pictures of what the lines look like on your 2015 so we can compare/contrast?

 

[skidro87]

I will try to post a picture tomorrow. I've been away on vacation and the fist has been collecting dust

 

[OffTheWall503]

Finally got a purge code, P144C. Described as "Evaporative emission (EVAP) canister purge valve - performance problem." Has anyone else gotten a similar code? Sent you a PM [MENTION=4567]Ryephile[/MENTION]. Maybe the system is detecting it's not getting anything back through the purge line since it's deleted.

 

[OffTheWall503]

I emptied my OCC today and realized the two fittings for the inlet/outlet on the can itself weren't fully tight. This may be the reason for the code.

 

[Ryephile]

I emptied my OCC today and realized the two fittings for the inlet/outlet on the can itself weren't fully tight. This may be the reason for the code.

That's very likely. The leak detection on modern cars is highly sensitive. Also if the re-route isn't plumbed exact then the system may not work correctly either.

I ran across this many times with the Abarth guys doing cavalier routing changes. It's actually important to get it right.

 

[OffTheWall503]

Haven't had an issue since I tightened my fittings.

 

[jeffreylyon]

So, if I understand this correctly, there's another vacuum line downstream of the throttle body with a check value that provides vacuum to the evap. canister when the engine is off boost and this mechanism provides vacuum when on boost by bleeding boost through a venturi, right?

The reason I'm asking is that I've got a Mishimoto induction hose on order, complete with the goofy looking octopus (I'm assuming it's a combination of a venturi and a check valve). I'm wondering if I can just cap the line on the induction hose, cap the evap. canister hose (at the hose end or at the junction at the opposite end) and forget about the octopus altogether.

Thoughts?

 

[OffTheWall503]

You would delete the purge line per Ryephile's instructions and cap the larger end of the octopus adapter. The smaller one is still being used.

I also have one of those induction hoses on order so as soon as I receive mine and install it, I'll post pics.

 

[jayrod1980]

Yeah you can't leave it altogether. I have the hose solution for the MAP intake, which is not as elegant as the Mishimoto but performs the same function. When I did the delete, I threw engine codes regularly. If I go back to stock I'll likely use the Ryephile method again as the Venturi chamber area on stock intake and the check valve are larger. I was getting some kind of back pressure that was jamming the weak check valve that is included in the MAP adapter.


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[jeffreylyon]

I'm still confused - if we cap the end that attaches to the charge pipe we're ensuring that there will never be vacuum on that side of the evap. canister circuit, but there will be on the other side while the intake tract is out of boost. I don't understand why we can just cap the boost side of the eval. canister circuit. If the ECU monitored the evap. canister circuit to ensure that there is vacuum even when the intake in under boost it would throw a code when we cap the charge pipe side.

 

[OffTheWall503]

So my P144C code came back. I will check the OCC fittings again and if that doesn't solve it, may need to remove it. Could also be this purge line delete but I'm doubtful that's what it is.

 

[jeffreylyon]

Can a custom tune just prevent that CEL code? We did an EGR delete on my son's Mazdaspeed 6 and a custom tune turned off all of the CEL codes it was throwing afterwards.

 

[OffTheWall503]

I wouldn't mind doing that but if this is actually an issue I'd like to know.

 

[skidro87]

I've had mine capped off on the 2015 for about 10000 km now and no codes not sure if it really does anything to an otherwise stock car though

 

[OffTheWall503]

Based on what others have said, it leads me to believe that it isn't the removal of the line that's causing the issues, but people that have upgraded their 2016 intakes are getting the same code.

This code wouldn't be related to the PCV or the oil catch setup right? Seems to be an intake related code. Or maybe it's even something else? My intake is stock though with only this removal done.

 

[808FiST]

I believe you might be right, as I too have a 2016 FiST. When I installed Mishimoto OCC and did not tighten the tubings very tight, I would have a whoosh sound like a boost leak from 3500 rpm onward. No code was thrown. I have the OEM intake w/o the modification that you did. So, I think this code may have to do with the 2016 intake tubings.

Based on what others have said, it leads me to believe that it isn't the removal of the line that's causing the issues, but people that have upgraded their 2016 intakes are getting the same code.

This code wouldn't be related to the PCV or the oil catch setup right? Seems to be an intake related code. Or maybe it's even something else? My intake is stock though with only this removal done.