Well the code is back. I'm beginning to think it has to be electrical of some sorts.

I got an extra green cap that goes on the EVAP test port and drilled a 1/4" hole in the center of it. Placed a brass fitting that would be put in a plastic water line for a fridgerator in the hole to be able to connect a vacuum hose. I took the schrader valve out and screwed the modified cap on and hooked up my vacuum gage.

I drove the car for about 15 miles with the gas cap off and it had 1 inch of vacuum all the time with the cap off. Isn't the cap suppose to seal off the system? No code was recorded during the drive.

One thing I have noticed is when the car is first drove the vacuum gage needle is very erradic for about the 1st 1/2 mile or so. The freeze frame info I got the one time said that the car was going 7 mph and the rpm was 660. Which would indicate the car was just taking off when it occured. Could the erratic vacuum reading cause the code to set. Isn't the PO440 code one for not enough vacuum?

My mom just called and told me the light was back on. I'll check the freeze frame info and see if it is the same as last time.

Any ideas from anyone?

440 is the general evap code, could be alot of things, like i mentioned earlier if you had the vac tool you could hook it to the lines and service ports see if they hold vacuum. there are a few different conditions that have to be met before it even checks the evap, its not likely that it would check it in random 15 min drive.

another thing you could check, my monte was getting a 0440 and i tracked it down to a sticky vent valve, i bought a new one from the stealership and it lasted about a year before it was doing it again. i took it apart and sprayed wd40 in there and actuated it a couple times with a battery on the bench and its been 2 or 3 yrs now without issue.

Whats the drive cycle procedure for the EVAP system to be test ready? Will the computer not set a code if the evap system is not test ready?

My autotap program showed that the evap system was incomplete while I was drive the 15 miles. I have another vent valve I could clean up and see if that helps.

Thanks for the advice.

Steve

the computer will not set a code until i tries a test and something fails. when the "readiness indicator" says the evap sys is ready then it ran the test. i think you have to have so many cold starts and a timer and fuel has to be 1/8th to 7/8 ths, maybe someothers i cant remember right now.

found this on answers.com, the temp would have to be 45 to 85 which wouldnt happen all winter for me
Evaporative Monitor:

Pre-req: no codes present, IAT & ECT between 45 and 85 deg f: barometric pressure above 75 kPa, fuel tank level between 26 and 74 %; TPS between 9& 35 %; evap solenoid is at 50% pwm within 65 sec of engine run time

-Idle vehicle 5 minutes until it is in closed loop

-drive 5 min at steady speed between 30 and 40 mph

-stop and idle 2 min

Thanks for the advice. I'll try changing the vent valve out after cleaning and checking it out first. I've changed the vent valve once but it was faulty so i put my mom'* original one back on. I have another spare one i haven't tried yet. I'll keep my fingers crossed.

If I can get the enhanced portion of my autotap program to work right it might help me to understand whats going on.

I'll let you know what happens.

I change the vent valve on my mom'* car. My brother and I cleaned and sprayed it with some WD40 and hooked it up to battery voltage to make sure it works.

I couldn't check the freeze frame data since my computer couldn't connect. Working on that as I write this. As soon as I can check the freeze frame data to see when it happened.

Next option is to start capping off vacuum lines in different areas to see if it will hold a vacuum and how long it will hold it.

One thing I forgot to mention was when the car is 1st started and the throttle is opened above an idle. The vacuum to the service port for the evap is erratic for about the 1st half mile driven and then sometimes it will do it when 1st taking off from a stop. Does anyone know if this is normal. I've watched a little bit about the EVAP system on youtube and one of them said it cycles the system. Just don't want to be trying to track down something that is normal for the car to do.

I got my autotap working again so I'll try and go to my mom'* one day this week and check what the system freeze frame info is.

I went to my mom'* and check the freeze frame info and code. It'* still PO440 and this time it was set while she was driving at 42 mph. Last time is was 7 mph. Doesn't look like it a take off problem.

I did have time to attach a vacuum gauge to the EVAP test port and found something strange. With the throttle open and it has 1 inch of vacuum on the gauge the fuel tank pressure sensor shows zero pressure.

How can it have vacuum pressure on the line and no tank pressure? Could it be a blockage in the line not letting the vacuum get to the tank. I did drive it that one day with the gas cap off and it had 1 inch of vacuum then too. Can a fuel tank pressure sensor not trip a code to be bad and still not register a reading?

Anyone ever have a problem like this? I think things like this only happen to my mom'* car. LOL

Steve

if im understanding what your trying to say,
the system is not always purging the fumes from the canister. the fumes from the tank collect in the canister and under certain circumstances purges the fumes from the canister through the purge valve and into the tb. its not always doing it and because of the valve on the canister its not going to be the same pressure in the tank as the line thats going to the purge valve.