P0446 CEL and emission problems

[JSin]

I have a 97 Eclipse GSX. I reset my original ECU and as some of you might know this caused the smog emission readiness tests to reset and they are next to impossible to satisfy. The solution many people have found to work is upgrading to a 99 ECU, which I did, this is where the problem exsists. Once I start to drive around on the 99 ECU with my OBDII reader linked and scanning, after about 10 minutes of driving 2 of the 5 readiness test will complete (both O2 sensors) and a P0450 error code will flash. But the CEL does not come on. Once I stop and restart the car, I get a CEL and only the P0446 error code. I've read through all the thread here related to the P0446 CEL and have yet to find a solution to this problem. In addition, when I open the gas cap, there usually is a release of pressure, but not anymore, thus I think it has to be related to fuel pressure somehow... I have taken the following steps to diagnose/remedy this problem.

1. Checked PCV Valve: good.
2. Replaced gas cap.
3. EVAP purge solenoid resistance: 32.4Ohms
4. Power to EVAP purge solenoid: .7V

Any ideas on the next step I can take or what could be causing this problem?

 

[grnchevyz]

Possible causes for P0446 CEL - EVAP Emissions control system vent control circuit malfunction.

1- Loose gas cap
2- Vacuum line off of fuel tank or evaporative charcoal canister
3- Bad evaporative vent solenoid
4- Bad wires to evap vent solenoid.

I suggest you check ALL vaccuum lines going to the fuel system/emissions system. While you're at it, check the rest of them

I see you changed the gas cap so we can rule that out. I'll have to cross my manual for the specs on resistance and power to the solenoid. But if I remember correctly they look alright...just the power...I thought at least 5v but I'll double check that.

Hope this points you in the right direction.

 

[JSin]

Possible causes for P0446 CEL - EVAP Emissions control system vent control circuit malfunction.

1- Loose gas cap
2- Vacuum line off of fuel tank or evaporative charcoal canister
3- Bad evaporative vent solenoid
4- Bad wires to evap vent solenoid.

I suggest you check ALL vaccuum lines going to the fuel system/emissions system. While you're at it, check the rest of them

I see you changed the gas cap so we can rule that out. I'll have to cross my manual for the specs on resistance and power to the solenoid. But if I remember correctly they look alright...just the power...I thought at least 5v but I'll double check that.

Hope this points you in the right direction.

Problem is, I think I checked all those. I've visually inspected all the vacuum lines in the engine bay, nothing seems to be damaged at all. I tested the EVAP purge solenoid and according to my maual its correct, I even checked to make sure it had power coming to it, which it did and I swapped out the gas cap. I don't know what else I can do. Could this be related to the EGR value and solenoid at all?

 

[JSin]

Oh wait, where is the EVAP vent solenoid? Hmmm...

Is that the same think as the EVAP purge solenoid... what's the difference?

 

[JSin]

I can't locate a vent solenoid on the 97 gsx, only on the 2.4L engine. Do you know something I don't?

 

[grnchevyz]

I will refer to my manual and post location.