Is there a doctor in the house? My Sheila is sick!

[7255]

2013 Chevy Sonic LT, ODO is 83,685. Throwing the following engine codes, as reported by the dongle at AutoZone:

P0171
Bank 1 system too lean

P0324
Knock control system malfunction

P0326
Knock sensor 1 circuit range

P0496
Evaporative emission system high purge flow.



The symptoms I'm noticing are just two:

Whenever I refuel, no matter the tank level, she doesn't start properly, as if she's not delivering fuel to the engine right. I have to push on the gas pedal to get her to start while the key is turned to make her start. That only happens when I add fuel.

Whenever I start her otherwise, a few seconds after starting, there is a knocking sound from between the rear seats. That sound doesn't happen when you add fuel, or I haven't noticed it at least.

Any ideas?

Sent from my VS985 4G using Tapatalk

 

[Natesriv]

A code P0171 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. There could be a vacuum leak downstream of the MAF sensor Possible cracked vacuum or PCV line/connection Faulty or stuck open PCV valve Failed or faulty oxygen sensor (bank 1, sensor 1) Sticking/plugged or failed fuel injector Low fuel pressure (possible plugged/dirty fuel filter!) Exhaust leak between engine and first oxygen sensor


P0324
Since the knock sensor is responsible for making the PCM aware of unexpected engine noises (primarily caused by an incorrect air/fuel mixture that leads to abnormal cylinder detonation), this code is often the reaction to another more serious problem. If other drivability codes are present, diagnose and repair those before attempting to diagnose this code. If the engine is running smoothly and quietly, and the code persists, the most likely cause is a faulty knock sensor. Frayed or broken wiring, corroded wiring and connectors, or connectors that are unplugged are also strong candidates. Some applications locate the knock sensor near the starter and the sensor connector is often broken during starter replacement.

Potential causes of a P0326 code include: Knock sensor connector is damaged Knock sensor circuit is open or shorted to ground Knock sensor circuit is shorted to voltage Knock sensor has failed Moisture in knock sensor connectors Incorrect fuel octane PCM has failed



Potential causes of a P0496 EVAP code include: Faulty purge or vent solenod/valve Plugged EVAP canister Failed EVAP / fuel pressure sensor Poor electrical connection Short electrical circuit condition (Hyundai, Isuzu) Faulty canister purge valve Blocked vapor canister Faulty vent solenoid Leaking EVAP system hose (Hyundai) Faulty purge flow sensor (Kia, Mazda)

Read more at: P0496 EVAP Flow During A Non-Purge Condition
Copyright OBD-Codes.com

 

[Natesriv]

all that's from the web...but I sense it's an airflow issue... something is leaking or cracked I'd say....


Guys?

 

[Stew]

When you refuel the system does an evap test, you can clearly see this on your LTFT with an Ultragauge so a problem with your purge flow seems likely given the symptoms you're describing. It sounds like it's running way too rich when it's performing the evap check, putting the gas pedal to the floor puts the engine in 'flood clear' mode, again this all makes perfect sense with what you're describing.

For the P0171 have you inspected the rubber tube going from your air filter box to the engine? The rubber breaks down causing an air leak after the MAF sensor. The knock sensor codes hopefully is just a bad knock sensor which isn't too expensive.