Originally Posted by
pizzaguy
I forgot some things:
1) Cars that sit a lot or sit a long time can develop corrosion on wiring pins and terminals, these, again, can cause erratic readings which can fool the ECU.
2) Cars that sit can suffer from chewed wiring if rodents have access to the car.
3) If the wire in pin 1 has unstable voltage on it, check the other two pins to be sure the 5 volt lead is SOLIDLY at 5 volts, if not, you must trace back to the ECU to see what is causing it to be unstable.
If the ground pin has more than maybe .05 volts on it, you must follow that wire to the ground connection to see where the resistance is.
You could have a system leak, but you could EASILY have a wiring/sensor issue that makes the ECU THINK you have a leak. Don't go too far in "fixing my leak" until you KNOW that the 'leak' is real.
Thank you pizza guy for the detailed suggestion regarding checking the sensor and wiring. That is some good advice and I probably should have started there before replacing parts like you suggested. So, I was able to access the fuel tank pressure sensor and hooked up my multimeter. Couldn’t really get much of a reading which I thought was odd (but I may not have been using the multimeter correctly) or I have a wiring issue somewhere. I waited for a while until I think the test started as well and didn’t get much results. Will try again. I did also measure the wiring for the purge valve solenoid and it jumped up (when I think the test was running or trying to run). I decided to also hook up my old purge solenoid to some alligator clips and touched them to the battery, the old one was making the open and close sound. I decided to then test the “new” one I replaced months back. It was bad! It wasn’t making any noise of opening or closing. Ridiculous amazon junk I guess. Should have tested it before I installed it. After I replaced that sensor and nothing changed, I replaced the charcoal canister shutoff valve so now we’ll see if that was the issue and go from there. If not, then back to wiring diagnosis and trying to see if I have a bad fuel tank pressure sensor or wiring issues somewhere. Fun stuff! Thanks for the help