P0442 small evap leak

[Dmflash]

Hey everyone, I'm getting a small evap leak on my 07 trailblazer p0442. I'm not noticing any symptoms other than really bad fuel economy. According to the information on the dash I'm getting 6.9 L /100km .
Other than that it starts fine, idles fine and seems to run good . So far I have replaced the fuel cap and vent valve at the back. I do notice a faint smell of gas on start up first thing in the morning.
Any ideas on what to check next would be appreciated, thanks.

 

[Mooseman]

Are you sure you don't mean 6.9 MPG? 6.9L/100km equates to 34 MPG. No way it's getting that.

Best would be to do a smoke test to find where it's leaking but the fuel smell might be pointing to something actually leaking fumes or gas from the tank. Check the filler inlet and hose for leaking and look for actual fuel leakage. Another possibility is a rusted through fuel pump module top. I'm dealing with a similar issue on my 07 where the fuel line on top of the pump has rusted through and leaking badly but since you're getting an evap leak code, I would suspect a leak into the tank itself. These fuel pumps can get pretty rusty especially in the rust belt. Your profile doesn't say where in Canada you are but I suspect it's somewhere that uses road salt or brine.

 

[Dmflash]

Are you sure you don't mean 6.9 MPG? 6.9L/100km equates to 34 MPG. No way it's getting that.

Best would be to do a smoke test to find where it's leaking but the fuel smell might be pointing to something actually leaking fumes or gas from the tank. Check the filler inlet and hose for leaking and look for actual fuel leakage. Another possibility is a rusted through fuel pump module top. I'm dealing with a similar issue on my 07 where the fuel line on top of the pump has rusted through and leaking badly but since you're getting an evap leak code, I would suspect a leak into the tank itself. These fuel pumps can get pretty rusty especially in the rust belt. Your profile doesn't say where in Canada you are but I suspect it's somewhere that uses road salt or brine.

 

[Mooseman]

^^^^

Is there a response in there somewhere?

 

[Dmflash]

Yeah you're right average econ 6.9 mpg . I am in Ontario Canada where salt in used. I don't see any leaks on the driveway or trickling on the tank.

 

[Mooseman]

The fuel filler pipe can also rust through so check that too.

 

[Chickenhawk]

I would follow Mooseman's advice. I had exactly the same thing - poor mileage, evap leaks and a faint smell of fuel. The lines and locking plate had rusted badly because salt gathers and sits on top of the tank. It is hard to spot the problem without dropping the tank.

It is almost impossible to remove the lines without destroying the fuel pump so if you are going to tackle this job, you might as well get a new fuel pump and locking plate in advance. You may also need a new fuel line.

 

[Mooseman]

Like me, get the straps, new bolts and U-nuts. And when I do mine, I will soak the whole thing in Fluid Film. Damn salt!

 

[Dmflash]

The fuel filler pipe can also rust through so check that t

Like me, get the straps, new bolts and U-nuts. And when I do mine, I will soak the whole thing in Fluid Film. Damn salt!

Today I cleared the code and immediately filled up , on my second start up the code popped back up. Last time I cleared the code I'm pretty sure it stayed off until I filled it up , so it's definitely looking like a issue with the fuel system.