Gas Cap--Inside Center--Audible Click ('97 5.0)

[mbruffey]

This is a follow up on thread http://www.explorerforum.com/forums//showthread.php?t=68834.

Have had driveability issues (lean/miss). Some indications of EVAP issues, but no codes.

Noticed in the thread listed above (final post) that the operator indicated he heard an "audible click" from the inside center as he lubricated the gas cap ring. Apparently he depressed it by accident.

I decided to check mine, just for kicks. Lo-and-behold, when I pressed on the center of cap, mine clicked too. I was unable to repeat the click, even after installing and uninstalling the cap several times.

What is it and what causes it to pop out?

Thx, LMB

P.S. Seems to drive better today. But I have not re-run the diags to see if will pass inspection routine yet. You never know if you have fixed a no-codes EEC-V problem until you have driven several days anyhow.

P.P.S. This is NOT about the audible clicks you hear when you tighten down the cap after a refill. (Or, at least it seems to be a different issue.)

 

[mbruffey]

! ! ! Solved ! ! !

That gas cap was the problem/solution. I have been working on this problem over a year! I kept noticing that the fuel pump made a zing followed by a kind of gurgle when firing up. After popping the center of the gas cap back in, I now hear a nice, smooth ZZZZZ - I - I - I - I - NNNN-G, and off we go! Runs better than she's ever run. (Now I will probably wreck it!)

See original problem thread here: http://explorerforum.com/forums/showthread.php?t=251776

OBD software alerted me to the fact that there was some kind of problem in the evap system (no codes, but observation of fuel tank pressure/vacuum, etc., and failure of evapris4 portion of test). Software is Alex Peper's obd2 software, which is excellent at getting into the Ford extended data using a PC (http://www.obd-2.com). I can scan a total of 228 different live signals. It showed me I had a miss, not associated with any particular cylinder, and that the O2 sensors were cycling properly. After that, it pretty much has to be vacuum leak or fuel pressure, right? I did fool around with the evap hoses a little--soaked some in PB blaster to soften around fittings, but it was the old gas cap center click that really solved the problem.

Cause of gas cap center needing to be clicked? I don't know. I suppose perhaps it's a pressure relief valve for the gas tank. Opens to prevent overpressure, then prevents proper fuel pressure build up. That will teach me to top off the tank!?

May similar justice be meted out to all tank-topper-offers!!

LMB

 

[willypedraza]

can this be posible ?

Missing a gas tank cap, can posible cause malfunction to a explorer 2000 ovh?

:roll:

 

[yavapaires]

Yes