under half tank yeilds check engine light

[darw_n]

I asked about this a while ago, thought I would ask again...

whenever my tank goes under half full, i get fault codes, I forget the exact codes, but they are massive evap leak, and misfires.

what would cause this, and it is directly linked to gas level, and not anything else.

thanks

 

[Chris-St Louis]

I asked about this a while ago, thought I would ask again...

whenever my tank goes under half full, i get fault codes, I forget the exact codes, but they are massive evap leak, and misfires.

what would cause this, and it is directly linked to gas level, and not anything else.

thanks

Gems uses the Fuel lever sensor to know when to run a EVAP test. It has to be less then 3/4 and more then 1/4 to run the test.

And, it runs the test at full engine temp at highway speeds under light load and throttle input.


I think you have a p0455 if you have a massive evap leak. Should be easy to spot.

 

[darw_n]

what should I be looking for, and where precisly?

the one thing though, I get the check engine light even when I am stopped, always at precisly 1/2 tank.

 

[Chris-St Louis]

Check the TSB Section...I posted a overview.
In a nutshell, the EVAP system makes sure that gas vapor isn't leaking in the envoirnment.
It checks for leaks at times by pressurizing the tank and seeing the lose of pressure. Bigger hole menas quicker lose.

Since you have a gross leak, it should be easy to find..... Broken line, Evap Canister, Solenoid, and such.

 

[darw_n]

got it, i'll crawl under her tomarrow, and post what I find, thanks much!

 

[WHM304]

Jesse, I was wondering if you were able to find the problem and what it was.

I have the same code, already reaplaced the gas cap, but it is still throwing the code. I'm not to familure with the Evap system so I don't really know what i'm looking for. What is the purge valve and the solinoid, and how do I check them? Do I need to drop the gas tank and look under there for problems? I checked all the lines and connections that i could find under the body and hood, all looked normal to me. Thanks for any help.

 

[darw_n]

well, I can't physically check now because of snow and rain, and I don't have a garage.

however, I am purposly running under a half tank and having the guys at www.trailhead4x4.com check it out for me, I will update when we figure it out, plus I will get the actual error codes then, so I can post them