I rebuilt the engine in my blazer about a month ago or so. Maybe a bit less. I have about 900 miles on rebuild now. Runs great and no more leaks!! But thats about where my troubles start. I apparently missed a ground wire to the rear of the driver side head. Started with throwing a code for the drivers heater circuit not working. So i grounded that circuit to the frame and thats been over with. But a day or two after doing that i get a P0446 code come up on me. It did happen right after a fill up so I cleared code, tightened cap, and let it sit. Was fine for about 80 miles then came back. So I chatted with a few mechanic buddys and they recommended changing the vent valve. Done. Came back. When I pulled the engine i snapped off the snout for the purge valve on the manifold. So I have also replaced that fairly recently.

The gas cap is in less than good shape. So thats my next try. The seal is pretty dry rotted and cracked. But i would think it would throw a P0442 ( i think) code for a small leak rather than a circuit malfunction.

Ive read multiple multiple multiple threads and story's on this across several sources. NONE of them have had a solution to the issue. Not one said " hey i changed part A and it fixed my problem!"

Is there a test for the vapor canister? Id rather test that before i just replace it. It looks like a PITA and its 100 bucks on rock auto even.

Cap first and will move from there. I will pick it up tomorrow and hope for the best. Thanks for any help you guys can give me.

Is there something I should do when replaceing things like this? Pull the battery for awhile? What am I missing here?

 

hey do a smoke test for the canister it will follow the lines to canister and filler neck just look for smoke to seep out, did you clear the code using a code reader?

 

P0446 means the PCM did not see a drop in tank pressure during purge. This is usually caused by a large leak in the EVAP system, (more than just a loose filler cap). If this is a 2 door, it's very common for the fuel filler neck to rust out and set P0446. Might be worthwhile to remove it and check it out. If that's OK, this link will take you right to the problem. https://blazerforum.com/forum/diagno...plained-35143/

 

I tried getting a glimpse at it when i was under doing that vent valve. I couldnt see a thing. Tips or tricks to seeing it? Or can i just reach around to see it? I dont even smell any gas after fillup or anything which is why i never once even thought about that being the issue. The fuel gauge is out though.. Maybe the gasket/seal for the sending unit?

Honestly im quick running out of give a darn about this car. Want to sell it and get something thats from this century at least.

Thanks for the tips though guys. Ill have a look and get back to ya.

 

Not the neck. It almost looks like it may have been replaced. Its solid and rust free. Clamps are tight too.

 

In the link in post #3, look at "Check for the following conditions:" It gives a list of possibilities.

 

Found a pin in my purge valve was bent totally to one side. So it wouldnt be in the harness at all. Lets see if this does the job.

 

Short answer is no. Long answer is I have other issues.

Must have missed a few ground wires in the engine reinstall and it must have been involved with these issues.

It spent the day at the shop today to tell me they didnt really find anything other than the fuel level sensor is reading high somehow or another. Said it is likely a lack of a ground knowing the issues i have.

So looking into ground wires tomorrow after work. Will keep thread updated as i find issues for the others who may or may not have this exact same problem.