No there is a port on the intake manifold you are suppposed to connect the supplied evap line to. Is there any way I can just plug this port and delete all the evap crap and delete the codes off the pcm?

 

Yessir. It's gonna be probably a month before I'm free on a weekend though.

 

Ok thanks man just let me know. You still have my number?

 

0260?

 

Yea

 

What's the solution for the vent?

Cap from a different application that fits the Cobalt, or modify the filler tube ?

 

almost done with this. (just have to reinstall tank, it's out for more work right now)

removed evap can from rear of car, de-pinned plug and removed harness to can.

removed evap line to front of car entirely.

took tank vent hose that originally went to evap can and removed the portion from the can back to the tee.

clipped the zippy ties that held the atmospheric vent hose (from evap can) to the filler neck (removed wheel and inner fender to do so)

attached new vent hose (5/8 fuel vent hose, gas and alcohol resistant, from a marine supply) with a stainless screened (more than it had stock !) vent, up into fender well, zip tied along the filler tube similar to stock, ran this hose down and attached it to tank vent tee from above.

VOILA!

the stock line from the tank now vents to atmosphere through my new vent hose with screened end, and the filler neck, and both tank vents (one for "breathe in" , the other for "breathe out" ) all tie into the one line. Shouldn't be any need for a vented cap at this point.

 

looking into this...sub'd

 

Oh yeah, this was done to my car about 5 months after my last post in this thread.



I connected the EVAP line in the engine bay to my AFPR and used it as my fuel return.

 

Home made regulated return kit?

Removed the stock regulator I'm assuming? This is what I started the other day. I just have my EVAP line crimped shut for now.

 

I attempted to turn off the codes and evap diagnostics to the system on my LNF, to see if the Long Term Fuel Trim wouldn't freeze when the solenoid was unplugged. No such luck. Regardless, the system freezes the LTFT.

It'd be great to be able to disable the system in the software. That way the computer/engine could run normally and safely. Having the Evap disabled helps a great deal with AFR stability (therefore also engine safety), torque around town, and how quick the power comes on. There's no telling what other calculations it goes into, so having it disabled would help in that respect over just having it disconnected and a code disabling it.

 

LTFT freezing really isn't that big of a deal though. A lot of tuners don't even use them

 

interesting....

 

My car has issues starting after refueling. I can't tell if my evap has gone to shat or my valve cover breather is causing it
Subd

 

Although I cautiously agree, my overall point is that if the LTFT is freezing, what else could it be doing behind the scenes that may be affecting the adaptation of the ECU and calculations? Everything is so inter-related that there could be other areas that are adversely affected.


It could possibly be your Vent Valve Solenoid, on the canister behind the gas tank getting stuck closed or your Evap Solenoid on the Intake Manifold getting stuck open.

Starting issues seem to usually be the Evap Solenoid related. Fuel tank filling issues are usually Vent Valve related.

I've had friends that have run their Cobalt without starting issues with the back (going to the turbo) vented to atmosphere. It wasn't the best setup, but it worked/ran. If you're talking about the line that goes to the intake just after the MAF, then yes that might cause an issue.

 

I see what you're saying. I have all my codes off and the evap line removed and capped for now. I didn't really think it would be an issue to keep it capped until I needed it for a return line. Tb is capped as well of course. Anybody else see a problem with it? I did notice the other day in hp tuners that my ltft's histo wasn't reading and I'm an lsj so it must work the same.

 

Replaced EVAP purge valve. car works again. Epic piece of ****

 

bringing this thread back because im looking to get rid of the whole evap system also but on a LNF.

whats everything i need to do? is it pretty straight forward? remove everything and plug vacuum stuff? any cons to getting rid of all of it? i dont mind fuel smell as im already straight pipe and can smell everything but what i DO mind is dangerous vapors that can ignite.

 

It's semi-straight forward. I don't know about the LNF, but I've noticed no side effects from it on my LSJ - no fuel smell, etc. There is some plugging to be done and some rerouting/connecting of things to be done back by the axle. Well, mine needed rerouting because I used the EVAP line as my return fuel line.

 

nice! yeah my main concern is if the car needs the evap for any reason. im sure i can tune out any issues but whatever. wanna make sure im safe to start yanking stuff lol