help me with my freakin purge function

[04snake]

I figured this out last fall with help from the GM tuners on this forum readin my logs, but wasn't given many suggestions as to work arounds so maybe someone has an idea now.

I setup my 99 LS-1 run at the optimum 13.0 and when I go to the track right in the middle of a pass, usually in 3rd, but sometimes in 2nd and 4th the car noses over because the purge function kicks in and starts dumping unmetered air (gas fumes) which bungs up all the calculations, adds a full 0.5 point of AFR leaner which then causes KR and I can't run the same number twice in a row.

Didn't think it was going to be that big of an issue because this shouldn't be my track car but the Nitrous brains optional sled is still a week or two away from making NHRA points passes so the poor SS has to try and get me some rounds.

I now log % purge and it is so obvious this is totally messing me up but I don't want to run a real-time tune to control the purge cycle switch and I know pro tuners cannot disclose how to disable pollution control but a PM would be nice if there is a neat way to disable it. I want this car to be a nice weather DD so I didn't want to remove all the crap they put on there so a way to temporarily disable that damn thing would be very appreciated.

I tried burping the fuel cap at the lanes but there is no pressure, the purge seems to want to happen right after a gear shift and the associated fuel pressure spike then halfway thru the gear the canister function goes to 0% and the car picks up and goes.


My chebbie needs to cover for my ferd one more week so if ANYONE has an idea, I'll test it out at the track this weekend!

P.S. I did go one round when the other guy redlighted but that will be the only way I can win with this purge canister silliness!

[04snake]

Hmmm..

I wonder where that unmetered air is coming from?


Now this line with a labeled "Evap Service port", I wonder if this has anything to do with my problems.

I wonder what would happen when I unplug this Sshhhh don't tell!