mikee30

Hi,
I have a 2005 Uplander LS with 77,000km. The check engine light is currently on with codes P0496 and P0455.
I am trying to figure out a problem that I have been having for about 2 years or more! When I go to fuel up (be it full tank or less), the car will crank over and not start. But if I give gas as it cranking, then it will start, and after a few erratic rpms...gets back to normal and I can drive off. The 2nd start after fueling is normal.

Here are some maintenance items I have done recently: new air filter, new oil, cleaned MAF sensor.
The truck also does a similar problem sometimes when I start and shut it many times in a short travel duration (for example, 6-7 stop/starts in a 2-3km drive).
I was going to replace the vent valve solenoid and purge valve solenoid, but dropping the gas tank seems like a big job for a problem that is manageable. Some shops told me it is not that and not to bother. The truck obviously has a gas cap, but is missing the small flap inside the filler tube that prevents the siphoning of gas out of the car. Some shops believed that was triggering the error codes, while other shops told me a missing flap means nothing.
Car idles perfectly, drives well etc... Gas cap is tight...
Any other ideas on things I can check? I was planning on attempting to clean the throttle body as I noticed some black around the flap of the intake...
Any ideas are welcome!
Thanks!

Papa Bear

Do you let the fuel fill nozzle "kick off" all by itself then stop filling... or do you try to get that last bit of gas into the tank to round up to the next dollar (to be sure it's as full as possible)?

mikee30

Thanks for the reply - I don't try getting that last bit of gas in....the problem happens if I fill up or even partially put gas.

tech2

check the purge valve...if its stuck open...when fueling; the tank vapours create a flood condition.
if any of the dtc are related to the purge valve, gross evap leak...it would all make sense.

the purge valve is not at the tank. easy way to verify this is to disconnect the purge hose and blow thru it...no air should pass when the engine is off. or remove the purge line at the throttle body before refueling...after fueling reconnect it and see if it starts normally the first time.