Evap Emissions Purge Flow CEL

[avishenoy1]

I recently installed the Crawford Power Blocks on my 2015 FR-S. During the installation I did not realize that I had disconnected the PCV vent hose and when I attempted to start the engine post install, the engine stalled due to the vacuum leak. I found the source of the leak, and reconnected the hose to the PCV valve outlet and clamped both the valve and intake sides to ensure it was sealed. The engine started after that with no issues.

However, a few days later the CEL/SL showed up. The DTC codes P0441 and P0455 were stored, indicating a large leak in the evap purge system pressure. I checked the PCV and CCV hoses again and made sure everything was clamped and sealed properly and cleared the codes. The engine runs without issue, however every 2-3 days since then (for about 3 weeks now) both codes have reappeared. I've been content with clearing them as a short term fix, however I obviously would like to fix the underlying issue so that I don't damage the fuel system.

Other than the power blocks, I have an Injen Intake, Openflash Header, and TRD exhaust, as well as the OFT Stage 2 UEL AT tune.

I had to pull on the intake assembly pretty hard to get the power blocks in but I've checked all the sensor connections around the manifold and everything seems to be fine. Techinfo has a document specific to the P0441 code, but I don't have a subscription. If anyone can get this, I would be in their debt.

Sorry for the lengthy post but I would GREATLY appreciate any help on how to diagnose/fix this issue.

[humfrz]

hmmmm.........interesting mods .......

Now, are you absolutely sure that the one of the "O" rings didn't slip out of one of the power blocks grooves when you installed them .... ??

You might re-check the bolts to see if they are still tight ...??

http://www.motoiq.com/MagazineArticl...d-Spacers.aspx


humfrz

[steve99]

When you google engine codes add the manufacturer in search eg "P0441 subaru" as some codes are manufacturer specific.

check fuel cap is tight, check the evap canister hoses

http://engine-codes.com/p0441_subaru.html


http://engine-codes.com/p0455.html

Possible causes
- Missing Fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- Incorrect fuel tank vacuum relief valve

Read more: http://engine-codes.com/p0441_subaru.html#ixzz3nNl55ZQI


Possible causes
- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking

Read more: http://engine-codes.com/p0455.html#ixzz3nNlUH564

[avishenoy1]

Originally Posted by humfrz

hmmmm.........interesting mods .......

Now, are you absolutely sure that the one of the "O" rings didn't slip out of one of the power blocks grooves when you installed them .... ??

You might re-check the bolts to see if they are still tight ...??

http://www.motoiq.com/MagazineArticl...d-Spacers.aspx


humfrz

I'm pretty sure that the O-rings are in place and the bolts are torqued to factory spec. I don't think there is a vacuum leak as the engine does not sputter or fluctuate at idle.

Originally Posted by steve99

When you google engine codes add the manufacturer in search eg "P0441 subaru" as some codes are manufacturer specific.

check fuel cap is tight, check the evap canister hoses

http://engine-codes.com/p0441_subaru.html


http://engine-codes.com/p0455.html

Possible causes
- Missing Fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- Incorrect fuel tank vacuum relief valve

Read more: http://engine-codes.com/p0441_subaru.html#ixzz3nNl55ZQI


Possible causes
- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking

Read more: http://engine-codes.com/p0455.html#ixzz3nNlUH564

I think I've narrowed the issue down to the gas cap, thanks! It seems to be the most common cause for these particular codes. I always tighten it properly so I ruled that out in the beginning, however I checked it yesterday and I hear a pop noise shortly after the click when I let go after tightening it. I think the spring may have gotten damaged causing the cap to not seal effectively.

[millikan6]

Originally Posted by avishenoy1

I'm pretty sure that the O-rings are in place and the bolts are torqued to factory spec. I don't think there is a vacuum leak as the engine does not sputter or fluctuate at idle.



I think I've narrowed the issue down to the gas cap, thanks! It seems to be the most common cause for these particular codes. I always tighten it properly so I ruled that out in the beginning, however I checked it yesterday and I hear a pop noise shortly after the click when I let go after tightening it. I think the spring may have gotten damaged causing the cap to not seal effectively.

Hey, quick question, were you ever able to solve the p0455 code? Thanks

[RZNT4R]

Always always always start with checking your work.

441 happens when its purging the evap system and it doesn't see the pressure change in the tank, 451 happens when it tries to use its little vacuum pump to test the system and it can't get the pressure to drop. The sealed part of the system is from the vent sol to the purge sol under the intake.

You had to tug pretty hard in the intake you say? Hmmmmm...