PDA

View Full Version : What is the function of 3 way joint on fuel evap system



knowmyhonda
08-22-2009, 07:46 PM
My 1998 Honda Accord 4dr EX had problem with code P1457. I went garage to fix it, first did smoke test and found the problem were bad leaking on canister valve and bypass valve. the technician replaced all parts and reinstall new canister set, valves and all hose and pipe, but there is plastic part call 3 way join look like "Y" he thought it was no sense to install and no place to connect it. I checked internet there is part in Honda fuel pipe system, but it does not indicate how to connect it.
1, Is there somebody know how to connect it?
2, what is its function?
3, Is there any impact on that system without install it?

Thanks a lot.

TexasHonda
08-22-2009, 08:31 PM
What year/trim accord do you have? Put in your signature line to avoid in the future.

good luck

knowmyhonda
08-22-2009, 09:05 PM
hi, TexasHonda,

I appreciate your respond, Do you have any cue or information?

TexasHonda
08-23-2009, 10:30 AM
Autozone has diagram showing 3 way valve arrangement.

Function is not described, but it appears to be two different paths; one for air to enter the cannister and one for air/vapors to leave the cannister, if the vent valve is opened by ECU. Normally vacuum is applied to cannister to pull fuel vapors to the intake manifold and vent valve is shut, but under certain conditions fuel tank pressure may need to be relieved or vacuum level reduced. The vent valve would open and one of the air ports would be active. It's likely a check valve that prevents reverse flow on one path. Not clear why it's necessary. There may be a filter to prevent dirt entering system on air intake path and other is direct path for air venting.

good luck

knowmyhonda
08-23-2009, 08:11 PM
Thank you very much for your explain, TexasHonda,

I still confusion about that, from the picture below, the part I mentioned is 11#(joint, three way), it is just a plastic tube, It looks the foot of 'Y' connect to 53# (Bulk hose, Fuel)and then to 36# (sensor, vent pressure), but it is not clear the two hand will be connect to where. may be one will be connect to one socket of 14# (Valve, two way) but where is another one to go? I think the air for canister(6#) is sucked from the the bottom (the side opposite against to 8# (Valve, canister vent shut)).
the question is why does the vent pressure sensor need fresh air from this 'Y' 3 way joint if one of its hand (suppose to 'left hand' here) no connection to other hose or something else. And also another hand (suppose to 'right hand' here) connected part will suck air or discharge something from connected part (maybe 14#?).
the EVAP system should be a close system except canister need to suck air for release the absorbed fuel in carbon to engine.

the picture please see attached file (the picture got from hondaautomotiveparts.com)

TexasHonda
08-23-2009, 08:43 PM
Read the autozone explanation and look at pics. Neither of the Y ends connect to anything.

good luck

knowmyhonda
08-24-2009, 09:02 AM
Sorry, TexasHonda, I could not find the information and pic you mentioned on autozone, could you give me a link or attach the pic here. You mean this Y is not necessary, right?

TexasHonda
08-24-2009, 06:50 PM
You may have to register to access the repair guides. Here's the link.

http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Emission+Contr ols&partName=Driveability+And+Emission+Control&pageId=0900c1528003a1af&partId=0900c1528003a1a2

good luck

TexasHonda
08-24-2009, 06:52 PM
I don't think the Y is absolutely necessary. I believe it's function is to simply cause air pulled into the carbon canister to be filtered, probably through a foam sock. The other outlet lets air escape but has a check to prevent air entering when pressure is below atmospheric.

good luck

knowmyhonda
08-25-2009, 07:50 AM
Thanks, TexasHonda, I very appreciate your help, it seem to let air suck in for purge canister and balance pressure, I will going to ask the technician to put it back.