EVAP system problems

[1Saucyyy_brz]

Im going to keep this simple and if you have questions please ask.

The codes: P0456(evaporative emissions system very small leak detected) P0441 (evaporative emissions sytstem incorrect purge flow)

Car history: 65K miles, been boosted (turbo) for about 20k miles, been built for ~10K. Car has AEM fuel pump and Full Blow Motorsports 550cc injectors

The symptoms: under casual acceleration the car runs really rich, in the 9's for AFR. When putting in more throttle input and building boost the car continues to run rich, until i hit full boost is when the AFR shifts to an unideal 13 or 14.

How long has this been happening? Months and months, i havent been driving the car much because i cant fix this issue and i dont want to do any damage to the car. Ive lost a lot of my passion and love for this car because of this issue. This is my third and final time posting about this issue on these forums before i take it to shop and pay the thousands it will take to fix this.

What have i done to try and fix the issue? Ive pulled out the fuel pump and housing and inspected all the lines, nothing to note here everything looked good.
Taken off the EVAP purge canister located under the intake manifold, looks perfectly fine and the lines going to and from it are in good condition. The only thing that could be suspect is the fact that the harness connector to the canister had to be cut off to wire in an electronic boost controller back when i first boosted the car, which never ended up working. So i did what i thought would be best and wired back in the purge canister using butt connectors... Everything was fine after that for a long time, then i bent a rod, built the motor and got a dyno tune. About a couple weeks after the tune this problem came up.

Any and all questions and conversations regarding this issue are more than welcome, please help me sort this issue out and get my love for my car back.

[jrhudson]

There are multiple threads regarding P0456. Check that o ring for the cap on fuel pump assembly. And i would first do a datalog and send it to your tuner. Your tuner should know what is wrong.

[1Saucyyy_brz]

Originally Posted by jrhudson

There are multiple threads regarding P0456. Check that o ring for the cap on fuel pump assembly. And i would first do a datalog and send it to your tuner. Your tuner should know what is wrong.

Ive looked through these threads, 90% of them point to the gas cap, which i dont think is the case since im running so rich.. but ill look into replacing it as it cant be that expensive. The other 10% of those threads either die off or say the problem just goes away.

[jrhudson]

Originally Posted by 1Saucyyy_brz

Ive looked through these threads, 90% of them point to the gas cap, which i dont think is the case since im running so rich.. but ill look into replacing it as it cant be that expensive. The other 10% of those threads either die off or say the problem just goes away.

Have you actually done a datalog and sent it to your tuner?

[1Saucyyy_brz]

Originally Posted by jrhudson

Have you actually done a datalog and sent it to your tuner?

The original tuner passed away, which bring up the complication of trying to find a new one and possibly getting charged just for him to look over the log. Ill see if the tuner that took his place at the job is willing to do so.

[RZNT4R]

I don't usually comment on weird issues with tuned setups because those are human-created issues and so don't usually follow usual failure rules, making them ridiculously hard to help with over the internet.

With that said, instead of forum posts, did you even look at the DTC descriptions before taking things apart?

P0456:

5 hours*1 after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

Leak detection pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure is measured. Reference pressure measured at start and ednd of leak check.

If stabilized pressure is higher than second reference pressure, ECM determines that EVAP system has a small leak.

P0441:

This monitor intrusively performs a functional check to detect incorrect purge flow. The monitor seals the EVAP system (i.e. isolate from atmosphere) by closing the EVAP switching valve intrusively after recovering from a fuel cut event. In the case of normal condition, and the commanded purge control duty ratio is more than 0%, EVAP pressure (gauge) will decrease due to engine vacuum and reach to the threshold value. However, in the case of malfunction condition (e.g. fuel cap open, purge valve stuck closed, purge line disconnected or blocked), if the EVAP pressure (gauge) does not reach the threshold within a predetermined time, the monitor determines a malfunction and stores a DTC.

The pressure is higher than threshold for 20 seconds or more.

If I had the car in my hands and had to take a stab at it, I'd seal the tank vent and disconnect the purge solenoid and look for boost leaking through it by graphing data from the FTP sensor.

[edit]

Even then, it may not be linked to your mixture issue. I would wish you good luck with it, but I'll wish you good fortune instead, issues like this on a modded car can be expensive to find and fix.