P1456 code and fuel vapour leak

Am chasing a double problem with 1456 code and a fuel vapour leak. Have looked at several posts on this forum, which were useful but will need some more advice in order to get this fixed.

Vehicle is 1998 Accord LX with 2.3 VTEC.

The car leaks raw gasoline fumes but only after the car has been running. The smell comes from underneath the vehicle, about where the rear seat is. The fumes dissipate after 20-30 minutes which suggests that the buildup of pressure in the tank is what is leaking out. Once the pressure leaks out, the fumes stop.

Along with this, the 1456 code activates but it is intermittent. Once I delete the code, it could be 2 months before it lights up again. It's not constant.

In trying to remedy the 1456, these parts have been replaced:
gas cap, canister, bypass solenoid and two-way valve.

Have done a visual inspection on the tank and hoses, nothing obvious although not everything can be seen well.

Thinking this through, it seems like it can be one of two things.

One - there is a physcial break / hole in tank or hoses allowing the pressure to escape even though the EVAP system is functioning (no 1456 or 1457 most of the time).

Two - the pressure is not getting evacuated by the system. Since the 1456 is not always activated, it would seem that the pressure sensor is functioning. Since there is no 1457 code, it seems that the purge solenoid is also working. Also, if there is too much pressure in the tank, the gas cap is supposed to release it. The fumes are escaping from under the car, not the gas cap.

The other ingredient is the dreaded ORVR valve on top of the tank. Not sure how it works and if it has any influence on the flow of pressure from into the EVAP system. Found a post on this forum on how to get at it but don't want to tackle this if not necessary.

Grateful for any insights on this one.

It will be interesting to find the problem, I have the same issue.

The EVAP system is not functioning properly and is leaking elsewhere. I have had this same problem for a year or two. If you're driving a while pull over and release the gas cap to see if a LOT of air pressure releases, if it does you may need a new purge solenoid. Just because the CEL is not on doesn't mean anything. The sensor could be broken as well. Just something to think about. EVAP in our cases is not happening to the full extent.

^

The link is for code p1457 which is leak in the evap system, code p1456 is for the gas tank and the fuel cap.
I had replaced the cap and I am sure ChrisD done the same, I think there is a vapor leak some where between the tank and the evap system.
I am sure someone had this issue before and can give us their input.

ChrisD said:

Found a post on this forum on how to get at it but don't want to tackle this if not necessary.

Click to expand...

Can you post a link to this post?

Here's a link on how to access the ORVR valve without dropping the tank.

http://www.driveaccord.net/forums/showthread.php?t=36190

This link points to the problem I think, I had replaced the 2 way valve and the canister and also the fuel cap, this is the only thing I have'nt checked.
It makes sense you can get p1456 code by driving without a fuel cap, I guess when the orvr leaks the system see it as tank vapor leak.

Thanks guys I will try this when it stops raining here in south Florida

Bumping this. I have a p1456 (have had it for awhile). I first replaced the gas cap, CEL came back on. Then I replaced fuel canister and shutoff valve per this thread (http://www.6thgenaccord.com/forums/showthread.php?t=38000). CEL came back on. Is the 2-way valve the next most likely candidate? I NEVER smell gas inside or outside the car at any time before, during, or after driving it btw.


Could this corrosion be a problem?




I also saw a small slit in this hose, I filled it with some outdoor silicon sealant.




Thanks, I'm sick of this code.