Emissions help

JOHN73738

Member
I am having trouble with my TJ sport 4 L. I have that pesky check engine light p0455. I found a cracked breather hose. I taped it up and cleared the obd and all was well. I then changed the hose and the light turned back on. Doing some serious head scratching here.

Anyone have any thoughts?
 
I am having trouble with my TJ sport 4 L. I have that pesky check engine light p0455. I found a cracked breather hose. I taped it up and cleared the obd and all was well. I then changed the hose and the light turned back on. Doing some serious head scratching here.

Anyone have any thoughts?

I would start by just clearing the code again. If you had the key on and unplugged something along with it the code will come back. If it does come back let me know
 
Spoke too soon,

Anyone have any suggestions? Going to replace PCV valves to start.

P0455 is a large EVAP leak. It's not related to any vacuum lines nor your PCV valve.

Start my ensuring gas cap is tight. If it is, replace it for cheap insurance. If that doesn't work, you need to look elsewhere. Common areas of leaks are cracked fuel vapor line, filler neck not sealing, or fuel pump top tank seal leaking.
 
P0455 is a large EVAP leak. It's not related to any vacuum lines nor your PCV valve.

Start my ensuring gas cap is tight. If it is, replace it for cheap insurance. If that doesn't work, you need to look elsewhere. Common areas of leaks are cracked fuel vapor line, filler neck not sealing, or fuel pump top tank seal leaking.

Surprised it even recognized the leak, what year is it? My 97 isn't smart enough to know its broken. If its that big of a leak you should be able to smell it and narrow it down.
 
Surprised it even recognized the leak, what year is it? My 97 isn't smart enough to know its broken. If its that big of a leak you should be able to smell it and narrow it down.

Well obd2 has been in place since 96 on all vehicles so yours should have the ability. Being that his threw the code tho I will say it’s prob a littler newer than your 97.

Also for the leak to be detected it only needs to be bigger than .002” big. Basically a pin hole should trigger it. A large evap leak is usually something like WJCO mentioned which would be a loose gas cap, something rusted apart, or just fell apart all together
 
Surprised it even recognized the leak, what year is it? My 97 isn't smart enough to know its broken. If its that big of a leak you should be able to smell it and narrow it down.

I had the same problem on my 2001. Hose cracked where it connected to the evap canister. I ghetto-repaired it with electrical tape and the code never returned (although I did fix it properly later on).
 
Well obd2 has been in place since 96 on all vehicles so yours should have the ability. Being that his threw the code tho I will say it’s prob a littler newer than your 97.

Also for the leak to be detected it only needs to be bigger than .002” big. Basically a pin hole should trigger it. A large evap leak is usually something like WJCO mentioned which would be a loose gas cap, something rusted apart, or just fell apart all together
While 97's may have the OBD2 I can also vouch that it doesn't ever tell me anything. Example, somehow on my trip up to Seattle to pick up the new motor the air intake hose somehow came off of the intake and I fixed it in Seattle when I checked under the hood to be safe. Also when my fuel pump went out it didn't throw a thing. Then again this is all assuming my check engine bulb is working too.

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Then again this is all assuming my check engine bulb is working too.

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I took the bulb out of mine ;)
97 is an in between bastard child. 98 and up have all the cool features and smarter computer. My tank vents to atmosphere after Michigan rust blew the line to the charcoal canister, no codes except for the missing o2 sensor.

You find your giant leak yet?



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