my question is should the Vapor Canister Purge Solenoid under the hood be "clicking rapidly" at any time?
06 ss cobalt, I got it and don't recall the Vapor Canister Purge Solenoid ever clicking like this. ran great for about 1 year after a bunch of work on it. but now ill start it, runs good for about 2 minutes then, the Vapor Canister Purge Solenoid starts clicking like crazy, and instantly the idle becomes erratic to the point where it normally shuts down the engine. it will restart and run fine until the Vapor Canister Purge Solenoid starts to click again. so I replaced the Vapor Canister Purge Solenoid with a new one, but does the same thing.

 

The purge valve kicking in like that is normal, need to get it checked for evap system leaks or a canister that's been contaminated with fuel. Both will cause engine stalling when the purge kicks in.

 

ok, I do recall when I changed out the Vapor Canister Purge Solenoid that it appeared to have some fluid in the top front connection hose to it.

 

I do also remember changing out the vapor canister vent solenoid and the filter but maybe I need to just replace the entire canister assembly.

 

Eh, I just deleted mine. If you have access to HPTuners or a tuner, it's easy enough to delete the codes and not have to mess with any of it.

 

I did scan it long ago and deleted the codes that it set off, but the last dozen or so times, no codes where tripped. OR are you actually talking a bout physically removing certain evap components?

 

You can use hp tuners to delete the evap codes that would cause issues and you can actually then just delete the evap system.

 

so what would cause the evap canister get contaminated with fuel?
I want to address this before I attempt to test run car as i just replaced the entire canister with a new one,
sensors, lines, fuel cap, and tank spout assembly.

 

Running the veh while filling the tank and topping off the tank after it shuts off is the two most common causes. The other is letting the pump decide to cutoff on its own, have seen where the pressure doesn't kick the pump out properly and it force feeds the tank. Usually it stops with just a mild burp of fuel out the filler but sometimes ive seen it not stop at some pumps that customers have reported to us and we went to check ourselves.

 

appreciate the info, any other possible causes?

 

finally got this beauty all back together. planning to take for a test drive this weekend, weather permitting. Hoping amongst a lot of other things that when he purge valve starts to click that the idle doesn't become erratic or stall engine and that that damn loose fuel cap message doesn't appear.

 

thanks to all especially KOLT, always a huge help and answers, thanks.

Well, took it for a test drive with all the new changes it ran perfect and handled really nice etc. for a while, all seemed good, really good, but then the purge valve started clicking, the idle became erratic and engine died again. would restart fine but then as soon as I'd let it down to idle speed the purge valve would click, then poor idle.
ughh.
thoughts.

 

took it for another test drive since the new shifter being installed and all shifting is smooth quite and easy, which made it even nicer to drive,
all other changes worked perfectly.
again it all seemed just fine until one of my stops at a stop sign where I waited long then usual to take off, the purge valve started clicking under the hood then the idle became erratic and engine died again. it restarted fine and ran fine again until purge valve would click, then poor idle.

thoughts.

 

I know it's expensive but HPTuners or a higher-end scan tool will be very helpful here. You can command each component of the evap system to activate then watch the pressures to see what's wrong. You're in a "throw parts at the problem" mode of thinking and you're just wasting money. It's time to get a proper diagnosis of the problem by either getting the proper tools or taking it to a reputable shop. I don't want to sound like a jerk, just want to help you get the problem fixed.

 

If you don't want to buy credits for HPTuners then I think just the scanner will do what you want here.

 

It's $299 without tuning credits. Really a pretty great deal, just as a diagnostic tool. I paid close to the same for the VCDS for my VW/Audis. VCDS, I think, is more like a GM Tech 2 diagnostic scan tool (no tuning capability). I wonder if getting one of those might be better in his situation? Looks like they're potentially a bit cheaper.

https://www.obd2tool.com/goods-1568-...ZUHolden).html