Evap question
08-01-2007, 07:27 PM
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Re: Evap question (NathanMorris)
Id like to know myself. I had the same problem when I did a LS swap and the JDM engine didnt have it. I just took out the EVAP purge control valve (think thats what its called) from the Civic engine and installed it on the new engine and ziptied it and plugged the connector. I htink you need to to pass emissions. So anyone that knows for sure let us know.
08-01-2007, 09:00 PM
#3
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I'm not sure if this is the Evap system, but i believe its a line that comes off the top of the gas tank goes into a one way valve type thing then comes off valve into the charcoal canister, with another valve thats connected to vacuum.
Once the vacuum is activated the gas fumes get vented under the car.
I think obd2 systems use a solenoid for a replacement of some peice of that setup i described.
I would look at the service manuals for the cars in question and compare both types of emission systems, I believe any obd1 and obd2 system compared should give you insight as to how they function.
I have no idea why gas vapor "from gas sitting in the tank" isn't simply routed directly into the intake manifold with some sort of check valve and would only activate once a significant vacuum is created at the throttle body.
Once the vacuum is activated the gas fumes get vented under the car.
I think obd2 systems use a solenoid for a replacement of some peice of that setup i described.
I would look at the service manuals for the cars in question and compare both types of emission systems, I believe any obd1 and obd2 system compared should give you insight as to how they function.
I have no idea why gas vapor "from gas sitting in the tank" isn't simply routed directly into the intake manifold with some sort of check valve and would only activate once a significant vacuum is created at the throttle body.
08-02-2007, 07:52 AM
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Re: (likwidchz)
You should use the evap system from the motor not the car.
The vapors come from the tank and rest in the charcoal cannister until the car is at cruising speeds then the ECU opens the purge solenoid to purge the vapors from the C. cannister into the manifold.
If you look at the CC you will see three lines off of it one from tank to the cc, one from the cc to the throttle body, and the one from the solenoid.
The vacuum from the solenoid lifts the vent door to purge.
This is the old system found on 88-91's 92-95 are similar but they did change a bit.
And now the newest systems have leak detection and a air pump to check the system with. The new system has two shutoff's called the frontdoor/vent and the backdoor/vent the ECU shuts both of these and then proceeds to pump air and check for leaks.
What the manufactures and CA are trying to do is have no vapors (Oil or gas) escaping into the atmosphere. Thus we have a PCV system and the Evap system.
Like was said you can try and add the solenoid and see if it will fly. Depends on what ECU you use really and what that ECU is expecting to see.
The vapors come from the tank and rest in the charcoal cannister until the car is at cruising speeds then the ECU opens the purge solenoid to purge the vapors from the C. cannister into the manifold.
If you look at the CC you will see three lines off of it one from tank to the cc, one from the cc to the throttle body, and the one from the solenoid.
The vacuum from the solenoid lifts the vent door to purge.
This is the old system found on 88-91's 92-95 are similar but they did change a bit.
And now the newest systems have leak detection and a air pump to check the system with. The new system has two shutoff's called the frontdoor/vent and the backdoor/vent the ECU shuts both of these and then proceeds to pump air and check for leaks.
What the manufactures and CA are trying to do is have no vapors (Oil or gas) escaping into the atmosphere. Thus we have a PCV system and the Evap system.
Like was said you can try and add the solenoid and see if it will fly. Depends on what ECU you use really and what that ECU is expecting to see.
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