Have a 1998 Forester, getting a p0440 code. I can see the hose going up to the filler neck has broken. I'm pretty sure this is the cause of my evap code ( judging by this post http://www.ultimatesubaru.org/forum/topic/127479-evap-leak-replace-charcoal-canister/?do=findComment&comment=1080854 ). But the hose is blocked off by the rusty metal pipe, doesn't seem like air is getting past it.

 

When my car is idling, even after warmed up and also when in neutral while driving, the o2 sensor voltage reads 0 on my obd2 scanner. It also idles oddly. When driving along, the o2 values flip flop up and down as usual, but when I let my foot off the gas, it floors to 0v until I give it gas again then it returns to normal oscillation. I'm assuming there's also probably a leak in the evap? The broken hose doesn't seem to be leaking, just plugged.

 

What do I do to fix the hose? Drill a hole into the filler neck and install a nipple and run new hose up to it?

 

Recommend you replace the filler neck. If it is rusted anything like what I replaced on my 99 OBW, then you will need to replace it. A rusty fill pipe surely has holes in it, which prevents the fuel system from pulling it's necessary vacuum. Compromised vacuum is what sets off the p0440 code. Dorman brand filler necks are widely available from on line parts houses. Cost roughly $40-$50. Prolly won't hurt to buy a new gas cap, as the rubber seal goes bad on old caps, as that too can set off the same code.

So the filler neck is making it idle weird?

 

edit: Reading the other thread about idling, I'm thinking I have two unrelated issues going on. I'm thinking I have a vacuum leak somewhere up front in addition to the bad filler neck.

Edited June 24, 201510 yr by destey

So the filler neck is making it idle weird?

No, I don't think so. Holes in the filler neck is an emissions issue, associated with code P0440.

 

Weird idle source is prolly else where. Like a vacuum leak some where. When was motor last tuned up with new spark plugs and wires??

 

When pulling codes, any additional codes present that you may have missed??

It was a vacuum leak. Read that other thread, then searched the board on how to find vacuum leaks, came across the carb spray test. Sprayed around the engine, it sputtered when I sprayed near the idle air control valve. Specifically around the gasket. Took it off. Tossed the gasket. Used gasket maker sealant, put it back together, it ran good. Sprayed it with carb cleaner just to make sure, and didn't change the speed of the engine so no more leak.