E420 Fuel Access Door Solenoid
 

My fuel access door has been sticking and I have been using the manual release knob in the truck to open it for the past 6 months. When I went to lubricate the access door solenoid today, I pulled the knob and it broke off. Now, I have a pair of vice grips connected on the stem in the trunk where the knob used to be.

Now that this happened, I am hearing a pump running (I'm presuming a vacuum pump) for about 30 seconds after I unlock the car doors and get in the car. It sounds like it's coming from under the right rear seat.

Could a faulty fuel access door actuator cause the pump to continue to remain on for 30 seconds after unlocking the doors? I'm thinking that maybe there's a small leak in the actuator and the pump is commanded to run extra to compensate for this. The doors still lock and unlock fine.

Thanks.

Right, it's not building up vacuum on the fuel door line and the pump will run longer trying to get vacuum, but will time out after awhile, so I suspect this is exactly what's going on and you need a new vacuum solenoid for the fuel door.
Gilly

Thanks, Gilly, for confirming this. At least it's only $35 at Fastlane.

Right, and I think just a couple 8mm headed screws hold it in. In the meantime you could just plug the vac line, the pump will sense vacuum in the line and shut off right away, if the other lines are all OK.

Thanks. That's what I plan to do. Can you confirm that the words "lever off" in the shop manual mean to just pry the pneumatic line out of the actuator?

Yes, "pry off" with a 7mm wrench, you sort of wedge it between the line and the end of the "claw" that holds the line on and pops it off pretty nicely.

At least if you have a decent wrench that isn't too clunky. A Snap On works good as it wedges into the gap nicely, a clunky cheap wrench might not go in there.

Thanks again. I will give it a try. I just didn't want to damage the line taking it off incorrectly. Hopefully a Craftsman 7mm will work.

Might or might not. "Craftsman" was sort of what I was implying. If you have a bench grinder, if it won't go in that gap you could just shave off some material on the open end of the wrench to thin it up a little. Just a Craftsman, right?;)
Gilly

I'm only allowed to fly them--they don't let me wrench on them; though I do admire the expensive Snap-on tools the A & P mechanics pull out of their tool boxes.

In this case, the Craftsman wrench worked fine and I was able to disconnect the vacuum line within a few seconds. While temporarily capping off the line for the fuel access door actuator, I accidentally broke another line that goes to the trunk lock. Then I realized that the whole line is brittle and needs to be replaced. That will be my next project. Thanks again.

disconnect the pump's power until you get the leaks fixed. The pump will wear out prematurely running that long, especially if it ingests dirt through the damaged line.

Got it. All the leaks are now fixed.