Lost_clearance

I am currently putting my engine back in, and i was wondering if i need to run the EVAP, It all its designed to do is minimize the amount of fuel vapor escaping, correct?, But will it make it read a code? since it will be reading no pressure in the fuel tank

Flexmyrex

You can get rid of the evap system but make sure the evap line from the tank is vented, do not close the system. An evap system also prevents the gas tank from collapsing/exploding during vacuum/pressure build up when the fuel is heated and cooled down. Depending on the type of evap system your car has the pcm may never know the evap system components are missing, on the other hand the newer hondas will throw a cell if a leak as small as .020 is present, the size of a needle.

YoungKadafi

so what your saying is the fuel tank could explode if you rig the venting line directly to your IM? thats how i have mine.

Flexmyrex

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by YoungKadafi &raquo;</TD></TR><TR><TD CLASS="quote">so what your saying is the fuel tank could explode if you rig the venting line directly to your IM? thats how i have mine.</TD></TR></TABLE>
no in your case it is still being vented since it is hooked up to the im. As long as you dont have the evap line completely shut from atmosphere you should be good. The gas cap also relieves pressure/vacuum and the two are designed to work together.

YoungKadafi

ok good this had me worried since its directly putting vacuum on the gas tank. Im sure the gas cap has some venting properties to it.

I really do like my setup, the hard line is connected directly into the IM, which has several benifits.

Since the pressure is not vented into EVAP canister, the 2way valve is always open, hence its always pulling in vapors from the tank which in turns = better mpg, and making the air charge a bit more rich. Its also cleaner looking in my bay.

Im also gonna build a small vacuum manifold (connected to the firewall) to connect my PCV valve, brake booster and EVAp system to, to further clean up the bay.


Oh also I still dont get a CEL since the vac line is still connected to the purge solenoid.

Lost_clearance

Alright this unit is confussing me, after the EVAP control canister vent shut of goes the Filter, where dose it go after that? and dose the vaccume line go to the throttle bodie or the intake manifold

thesmogman

It was a little confusing to me to but this is how it works.

1. vent line from gas tank straight to cannister(the cannister holds the vapors built up while the car is sitting)

2. On top of cannister or near it there is a vent (AKA purge control valve)that is controlled by the ECU via a purge solenoid. (The ecu decides when activate the solenoid to open this vent to purge the vented vapors)

3. purge line from vent to IM. (this connects to the vent controlled by purge solenoid/ECU)

When cruising the ecu will activate the solenoid to open the vent and vent the vapors to the IM then close it to provide no vacuum leaks.

If you need more let me know

YoungKadafi

again all different engines/2dr/4dr's varry in operation. 4drs are different than some of the 2doors. The honda service manual displays the different styles. The 1996 d16y8 4dr is the easiest to work on for the OBD2 versions. anything else has a crap ton of sensors which will light up the CEL after 2 malfunctions.

thesmogman

Yes obdII is a little different. but the principals are still the same.

If you are refering to the new leak detection evap systems it is basically the same with one added vent and a air pump.

The ECU will close off the purge vent and the vent on the bottom of the cannister then starts up the air pump to pressurize the evap system to check for leaks, that is all.

kelly

Why do you think that stock uses the canister rather than routing the fuel vapors right to the intake manifold?

Routed directly to the intake manifold, the entire intake tract can fill up with fuel vapor, this could result in a big boom. It also means that the fuel vapor can still escape to the atmosphere through the air filter.

Hooked directly to the tank, you will always be pulling a vacuum which will pull air in from the gas cap. Your setup encourages vaporization of the fuel by always pulling a vacuum. Stock does not pull a vacuum on the tank, it simply pulls air through the canister. The tank will only vent vapor to the canister when there is a little pressure in it.

If you are not going to use the evap system, it is better to just run the vent line out of the engine bay or you can cap this line and the fuel cap will take care of the venting either in or out. However, the pressure relief at the cap will be decently higher than the pressure relief to the evap canister. You can see how much pressure it takes for the cap to vent by trying to blow through the relief valve. It is significantly more pressure than it takes to open the two way valve.

If you just vent the cap by say drilling it, then you will also be encouraging vaporization. It is better to have no or a little pressure in the tank which is how stock runs it.