So i just bought a 97 ss M6 with 94,000 miles. it's been running great, but all of the sudden the service engine soon light just turned on while i was driving. i put synthetic motor oil in the car the day before and was wondering if that could of tirggered the light. would a fuel injection cleaner/octane booster help any? and comments would be appreciated since i dont know much about the OBDII. Thanks!

 

Probably just a coincidence. Bring the car to somewhere like auto zone and they'll read the code(s) free. Post when you get them....

 

OK, i got the codes. There were two of the same codes: PO441 . The scanner said EVAP Emission Control System Purge Flow Fault. Any idea as too what might me causing the check engine soon light with this information. i got rid of the code for the time being, i guess i should just wait and see if it comes back on. thanks for the tip about the auto zone scanner!

 

I see this code a bit at work (Mazda). Basically the evap purge solenoid had taken a dump.

If I remember right, this solenoid manages the airflow from the gas tank to the charcoal canister. Then ones at work usually get stuck open, so they will not hold vacuum, sometimes even causing enough of a vacuum leak to set other codes too. We just replace the suckers and clear the code as this is a know issue and the part has been revised.

If something similar has happened to you, find where your solenoid is (somewhere in-line with the charcoal canister and a vacuum source) and hook up a vac pump to it. The default position is 'closed', so, in theory, you should be able to pull all sorts of vac. Your's may have failed from age or gotten clogged w/dirt, but you're probably gonna need to replace it.

If someone with more LT1 knowledge than me could back me up or shoot me down, it would help out. But, that's my best stab at it. Hope this fixes it.

 

P0441 sets when the PCM commands the EVAP purge solenoid to open, and the vacuum detector switch does NOT see a vacuum. Could be the solenoid stuck closed, or plugged up with carbon particles. Or it could also be a faulty vacuum detector switch.

The LT1 EVAP purge solenoid is on a bracket on the passenger side of the intake manifold. Shoebox has a photo, and a complete schematic of the entire EVAP purge system, including the location of the vacuum detector switch (#11 in the diagram):

 

Thanks for all the imput guys! you have been extremely helpful in pinpointing the problem.

 

I went to the delear to get the parts (EVAP solenoid and vacuum detecor) and they said that the code could have been set by anything in the EVAP system. Could it be a faulty gas cap that is triggering the code??

 

Unlikely, gas caps usually set EVAP Leak codes. P0455 is a Gross evap leak (really big leak). Less severe would be a p0442 - small evap leak.

 

I just purchased the EVAP purge solenoid and attempted to replace, but the bolt which holds the braket that carries the solenoid is extremely small and difficult to get to. would you guys have any tips on how i could remove the old solenoid and avoid paying the dealer $100? Thanks!

 

Is it possible the solenoid can be wiggled off that bracket?

Edit: I looked at the bracket and the bolt underneath it. Even tried to get a socket on it. It definitely won't wiggle off because one edge is bent up to prevent it, so the bolt has to come out. Someone has to have done this.

 

OK, here's how you do it. The little bolt is a 7mm. You need a 1/4 inch deep well 7mm socket and 1/4 inch ratchet. The deep well is just long enough to reach the bolt head. You don't have to take it all of the way out. Just loosen it enough to lift the bracket up. You might want to pick up the s shaped vacuum hose and the top vacuum hose. Both of the hoses on my car were cracked, and when I pulled them off, that finished them. It might be easier to put the end of the top hose that goes to the throttle body on first.

 

i have this code also, only usually thrown when i push the car hard, or just when i start it up. i have a scanner and just clear the code. am i causing any long term damage by doing this? there doesnt seem to be that much info on this problem, other than whats stated here. moparman, did you notice your idle being rough? imthinking about replacing the purge valve, how much was it?

 

No, didn't notice a rough idle. I think solenoid was around $23.

 

it is possible that a stuck open purge valve will cause bad idle. It's more or less a vacuum leak. no permenant damage, but its a cheap, easyish fix.

 

any chance local parts stores would carry this part?