Fuel delivery
Asked by GuruHZ8JR Jul 03, 2019 at 04:56 PM about the 2000 Ford F-150 XL 4WD Extended Cab Stepside SB
Question type: Maintenance & Repair
I have a 2000 F150 with a 4.6 liter engine and i am
expirencing a vacuum in my fuel tank as tank
empties . Any ideas as to where a wasp nest may
have clogged up a ventilator ,cause the truck did sit
up for about 2 years
2 Answers
You need to check out the EVAP system for clogs. Look up an EVAP diagram on the web.
Not sure about the 2000, but had a similar problem with a 2010, which caused the engine to run erratically. It was the evap system. on the 2010 the evap system runs a test to make sure fumes from the tank are not escaping into the air. It does this by pulling a vacuum on the system while running. If the purge valve does not shut off, and continues to pull a vacuum, the results are what you are seeing. My owners manual states to never fill the tank past the first automatic click-off. Of curse I never did that, not reading the manual. The result was raw gasoline being pumped into the charcoal canister, then into the vacuum pump, ruining it. If the vacuum gets too great, the fuel tank will collapse like a aluminum beer can being sucked on. You may want to visually check your fuel tank to see if it was damaged.