hi everyone, new to these forums but not so new to cars and other hyundai forums. the other hyundai ones are crap...i know there's a couple guys from hyundaiperformance who will know me. anyhow, up in the great white north (kinda hot right now though lol) and i've been doing a lot of my own car work for a few years now...learned a lot and i can take on most jobs now. biggest jobs i think i've done is a differential rebuild on my old toyota (had to learn how to do it RIGHT), did the clutch in the accent and next i'm working on rebuilding the transmission....or a full autopsy at the very least. i've written a few guides and willing to do more. not much into performance mods on the accent - i don't see much point with the 1.6L and i'm far too lazy to do a beta swap right now - but i know enough about that side of things. saving up for a car with a bigger engine to turbo the sh*t out of



you'll notice that i often share problems i'm not sure on just to get some ideas going. i'm rather good at diagnosis, but it does help to have someone else to bounce a few ideas off.



anyhow, odd problem i've been having with my accent. i've traced it down to a leak in the EVAP system somewhere and i'm looking to see what you guys think or if there are any parts known to fail in that system. i've noticed that this problem is VERY common as these cars get older, so i'm wondering if there's a specific part that tends to fail...and if there's a cheap fix for it....like silicone and some aluminum tape lol.



car is a 2004 accent GSI, 1.6L, manual. no real mods to speak of. just added in remote locks, power windows (was crank) and new deck/speakers.



here's the problem: when i fill up the gas tank i get misfires at idle. very subtle, i can't even really feel it if it weren't for the engine light b*tching at me. what i believe is going on is that there is a leak in the EVAP system causing a vacuum leak when the system purges the gas vapour to the intake. so, fill up and tank pressure rises. the valve behind the intake manifold (PCSV i think) opens at idle to purge the excess pressure. vacuum leak is created and engine starts swearing at me.



to confirm this problem: seems to happen at idle only when car is filled OR if its been sitting in the hot sun for a while - also creating more vapour. PCSV logic is to purge at idle. also, disconnected that valve and no misfires which i think proves the problem.



hoping for some ideas before i start buying parts...can't find a flow schematic or ANY service info for the life of me on that system. any parts known to go? can i access everything without dropping the entire damn gas tank?



thanks!

 

My 99 tiburon with 192,000 miles has a EVAP system leak too, the check engine light just came on 2 days ago. Think it could be the charcoal?

 

The first place I would look is the gas cap. Do you have a code with your CEL? If your purge valve goes bad it usually shows up as a code. When it died on our Tib it wouldn't even allow the car to start after filling up due to excessive fuel fumes being pumped into the IM.



If your misfire only happens for a short time after refueling then runs fine I think the purge valve is a likely cause.

 

<--- also wants to know what code is set.



I have a funny feeling about your EVAP hoses being a little cracked, but that might not be it.

 

I'm with sks



The misfire at idle is most likely the purge valve staying open, it should normally only open at highway speeds when not much power is needed.



I would go ahead and replace both purge and vent solenoids assuming they are both the same age

 

when i remove my evap hose from the back side of the solenoid, the can hear it opening and closing at idle. Can even feel it if I put my finger over the hole.

 

wow so far i love this site! other sites i'd put this in and get nothing...complain about it and the mod b*tched at me. people here are actually trying! thanks guys!!



ok so the trusty code scanner says P0441 evaporative emission system incorrect purge flow. i also get either misfire on cyl. 1 or 4 after i fill up, sometimes random misfire. same sh*t different pile really.



going to take a look at that valve next to the charcoal canister. i did check the PCSV that is directly behind the intake manifold and appeared to be working correctly. attached a tube and tried blowing in it seemed to hold fine. when voltage was applied it seemed to open correctly.



only thing i'm thinking here is why wouldn't this happen constantly instead of just after a fillup? goes away shortly after i drive around for a bit...trying to figure out the logic of the system, is there a pressure sensor to tell the ECU when to open the valve?

 

On most cars there is a gas tank pressure sender that sends data to the pcm.



Based off that data and engine load and other variables it releases that pressure through either valve accordingly.



After you fill up your car the presence/pressure of gas fumes is more abundant, thus creating a very dirty air mixture going into your intake. Once the fill up fumes are gone, as you stated, the misfire will likely not be felt but possibly is still occurring. That's what made me think your purge valve is stuck open. Dirty air at idle

 

thanks SR, thats great info. i think there is a secondary valve next to the charcoal canister so it could be that one. i didn't think of it that way, i was thinking more along the lines of vacuum leak.



so i need to check out that valve for sure, would a new gas cap be worth trying? it DOES pass emissions with flying colours btw.

 

COMPONENT LOCATION



GENERAL DESCTIPTIONDTC DESCRIPTIONDTC DETECTING CONDITIONItem

Detecting Condition

Possible cause

Monitoring Strategy

● Rationality check

● Open in battery circuit.

● Open in control circuit.

● Short to ground in control circuit

● Faulty PCSV

● Faulty PCM

Threshold value

● Lambda controller : -0.06-0.06

● Air mass through idle control valve < 0.8kg/h (1.7637 lb/h)

Enable Conditions

● During Idle and vehicle standstill

● Coolant temperature > > 70 degC(158 �F)

● Altitude (model) < 2500 m

● Integrated purge mass > 2grams

● Closed loop control enabled

Diagnostic Time

Fail Safe

● None

<br xmlns:myobj="urn:my-object">MONITOR DTC STATUS1.Connect scantool to Data Link Connector(DLC).2.Warm up the engine to normal operating temperature.3.Monitor the "EVAP.PURGE VALVE" parameter on the scantool.



The data shown above is only for reference and there may be a little difference actually.Service standardIdle : 0 %1000~3000 rpm : 1.5 ~ 35 %4.Is parameter displayed within specifications?



▶ Fault is intermittent caused by poor contact in the sensor�s and/or PCM�s connector or was repaired and PCM memory was not cleared.Thoroughly check connectors for looseness, poor connection, bending, corrosion,contamination,deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.



▶ Go to "W/Harness Inspection" procedure.ACTUATOR TEST MODE1.Evap. Leakage TestEvaporative Emissions Systems (EVAP) Leak Tests can be run by the Scan Tool. The tests are automated and provide either a pass-fail result or directions to check for DTCs.



(1)Connect scantool to Data Link Connector(DLC).(2)Warm up the engine to normal operating temperature.(3)Perform "07 EVAP. LEAKAGE TEST" mode(4)Is DTC P0441 set again?



Go to "W/Harness Inspection" procedure



Fault is intermittent caused by poor contact in the sensor�s and/or PCM�s connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection,bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification vehicle Repair" procedureTERMINAL & CONNECTOR INSPECTION1.Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.2.Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination,deterioration, or damage.3.Has a problem been found?



▶ Repair as necessary and go to "Verification of vehicle Repair" procedure.



▶ Go to "Power Circuit inspection" procedure.POWER CIRCUIT INSPECTION1.Ignition "OFF"2.Disconnect PCSV sensor connector.3.Ignition "ON" & Engine "OFF"4.Measure voltage between terminal 1 of PCSV harness connector and chassis ground.



5.Is measure voltage within Specification?



▶ Go to "Control circuit insepction" procedure.



▶ Open circuit or short circuit to chassis ground between PCSV harness connector and battery power circuit.▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure.In case the voltage at terminal 1 of PCSV is 0 V when PCSV is disconnected.▶ Possible cause:Open or short circuit in battery power line after fuse(15A INJ)CONTROL CIRCUIT INSPECTION1.Check for open in harness(1)Ignition "OFF"(2)Disconnect PCSV sensor connector.(3)Ignition "ON" & Engine "OFF"(4)Measure voltage between terminal 2 of PCSV harness connector and chassis ground.



(5)Is measure voltage within Specification?



▶ Go to "Component Inspection" procedure.



▶ Open circuit between PCSV harness connector and PCM harness connector.▶ Short circuit to chassis ground between PCSV harness connector and PCM harness connector.▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure.In case the measured voltage is 0V when checking control line▶ Possible cause:If the measured voltage indicates 0V,the problem is that control line is open, so check the open circuit between terminal 46 of PCM and terminal 2 of PCSVCOMPONENT INSPECTION1.Check Operation of PCSV(1)Ignition "OFF"(2)Disconnect valve connector and Remove Purge Control Valve.(3)Check that no air flows through valve.(4)Apply 12V and a ground to 1 and 2 terminals of the Purge Control Valve.(To sensor side)(5)Verify that air flows through valve



(6)Does Purge Control Valve work properly ?



▶ Substitute with a known-good PCM and check for proper operation. If the problem is corrected, replace PCM and then go to "Verification of Vehicle Repair" procedure.



▶ Substitute with a known-good PCSV and check for proper operation. If the problem is corrected, replace PCSV and then go to "Verification of Vehicle Repair" procedure.The purpose of measuring injector resistance is to find if the open circuit is in the component.So,check the continuity between signal line and ground line.VERIFICATION OF VEHICLE REPAIR1.Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code (DTC) which has been diagnosed.2.Using a Scantool, Clear the DTCs.3.Operate the vehicle within conditions noted in the freeze frame data or enable conditions.4.Monitor that all rediness test have been verified as "Complete"5.Are any DTCs present ?



▶ Go to the applicable troubleshooting procedure.



▶ System is performing to specification at this time.SCHEMATIC DIAGRAM