When replacing the fuel filter gas kept coming out of the fuel line on the tank side?

DUVALL

MEMBER
1999 CHEVROLET S-10
4.3L
V6
4WD
MANUAL
277,603 MILES

I was changing the fuel filter on my S10 and noticed the gas kept coming out of the fuel line on the tank side. This is the third time I have changed the filter on my truck, and I don't recall it doing this prior. I was wondering if this is normal. The gas cap was on the truck. So, my question is, is this normal or do I have a bad fuel pressure regulator on the tank or is something else wrong? Thanks in advance.

1 Reply

AL514

MECHANIC
4,795 POSTS

Hello, this is probably happening because it's summer and hot outside. Pressure rises in fuel tanks during the summer pretty fast during summer. Another possibility is that the Vent Valve may be stuck closed. Have you had any issues with filling the gas tank? For example, the handle at the gas station shutting off repeatedly? If not depending on how much gas was in the tank, it may just be normal pressure build up. Taking off the gas cap will help.

The Evap system will run its self-tests when the vehicle is first started up, when the Intake air temperature sensor and the coolant temperature sensor readings are very close to each other. Barometric pressures are correct, and fuel level is correct. When all these conditions are met the engine computer will shut the Vent valve, open the purge valve and allow a vacuum to build in the gas tank and Evap system, then it monitors the system for leaks by monitoring the rise in pressure from vacuum or lack of pressure. You will have a check engine light come on if any tests fail.

https://www.2carpros.com/articles/how-emission-control-systems-work