QuestionHi,
I replaced the fuel lines on this truck, they were petrified, with metal and spliced with high pressure hose where needed. 3 lines total, 3/8 main fuel, 5/16 return and 1/4 vent line I think. I drove to the gas station 8 miles away and while taking off the gas cap noticed alot of pressure coming out and then equalized after removing the cap. It didn't seem normal to me to have this much pressure. The same occurred on the return trip and I removed the cap again to check. Is there something that may be blocked, am I missing something here or are there things I can check to make sure it is venting properly? Thanks for the help.
AnswerHi Mike,
I looked in my Haynes manual for Sonomas, and it shows the canister is back by the left rear quarterpanel, near the tank.
There is a line to the charcoal canister, and then there is a control valve to port the collected vapors to the intake manifold.
Depending on the system you have, there may be a ported vacuum operated vent valve, a manifold vacuum operated valve, or an electronic valve operated by the ecm.
You may need to check that valve, and make sure it is operating.
Parts houses have the Haynes manuals, and you might be able to stand there and browse thru one.
You can also read them at the public library, and at Hastings book stores.
At the library, refference section, they also have the regular shop service manuals, with troubleshooting charts.
Van
