Divot

No, I'm not starting an internet hoax. I take it in for the emissions test and jokingly ask the tech if I passed. He said I failed because of the gas cap.

They hook the gas cap up to some vacuum hose thingy. The manager said these things fail all the time. So often, that someone opened a store right next door selling gas caps. $8 later and I'm good to go.

GMAFB.

s4for5

They just happened to have exactly the right gas cap to fit your year/model car?
I'm calling BS on this entire post
Just my opinion my opinion, yours may differ.

DWPC

You'd have had a "check engine" light for a leaking gas cap on any car built since the late 90s.

Divot

Oops, caught by the smartest guy in the room.

Gas caps are VIN specific, not just year/model. There is no interchangeability and over a million possibilities. And having a steady stream of people driving past your "Failed Gas Cap, We Have Them!" sign, that just failed over a gas cap, it wouldn't make sense to carry as many styles as possible.

If NAPA has in-stock gas caps for an '04 Cayenne, why would you doubt this guy does?

Divot

I'd have thought the same thing, but no CEL. (Kinda like if you don't close the gas cap the whole way, you get a warning.) I just think they test at a pretty high pressure. When the tech said I failed because of gas cap, I thought he was joking. I'd never even heard of a gas cap test before.

garrett376

You must not be in California? They've been doing the gas cap test for years in San Diego.

mudman2

XR4Tim

California's the only state I can think of that still does a gas cap test. It is most likely BS though, since the Cayenne's leak detection system is very sensitive to even small leaks - you would have gotten a check engine light. In fact, the reason that most states with emission testing don't require a gas cap test on newer vehicles is because the EVAP system does a self check, so scanning the car takes care of that.

Divot

You can add AZ to your list of gas cap states. I bought a new cap for my 996 while I was at it, as it had to be tested next. I saw small cracks in the rubber o-ring inside the old cap. I'm positive that would have failed, too. Neither was throwing a CEL, or, I just ignored it, on both cars, for months. Either that, or they test the caps under much higher pressure than normal vehicle operating pressure.

Dennis C

Colorado does the gas cap check. My Audi Allroad Quattro failed a few years ago.

Divot

You must have been ignoring the CEL.

DWPC

Its not so much that the test failure raises eyebrows...it's the bit about the guy with the gas cap shop. How many gas caps would one need to sell to pay the rent?

Renn 951

My old C-S failed Virginia inspection once because of the gas cap, and there was no CEL. I ordered a replacement OEM cap from Sunset Porsche, and based on the last two digits of the part number it seems they had "upgraded" the part several times, so I think they did have some issues with them.

Divot

I also was told it was BS by some (ahem) because a failed gas cap would always trigger a CEL.

I'll go back, take a pic, and ask him how many gas caps he has to sell to pay the rent.

ltc

I think the important question is "exactly what did Pops put into your gas tank BEFORE breaking the gas cap rushing to put it back on"