G Man

I have reinstalled the emissions equipment that the PO removed from my car. The city I live in does not require emissions testing but surrounding areas do and I am attempting to sell the car. Took the car to a test station in Reno today and had the car tested. The guy doing the testing had a problem with my gas cap because when he removed it from the car he did not hear any release of vacuum pressure. Does that sound right? He said if the car were being tested for registration purposes he would have to fail it because of the gas cap. My cap does not have a rubber seal on the inside but there is a seal of sorts on the threaded filler neck. The cap is not cracked or broken. I know there was a recent thread about this topic so I will go back and look that over again. The test was completed and the guy says the car passed fine and gives me the paperwork. There are no readings on the paperwork. It just says pass. I asked him if I could get the readings of the test and he tells me they are not available but that the car is running "really clean" because it passed after only 31 seconds of testing, whatever that means. They don't do the rolling dyno test, just put a sniffer in the tail pipe and a clamp on one of the plug wires. The engine is then run up and held at around 2000 rpm and the test is run. I have not had a vehicle checked in over 20 years so am not very familiar with the process.

Podguy

Jim,

I do not think the cap has a seal. There is a green seal on the tank. Here in california they do not test the 928 gas cap because it is unique and does not have an adapter.

The tester should have generated some numbers. The cats on the 928 function well and will knock down the emissions to almost nothing. The one failure point is the O2 sensor. If the NOX is high then the O2 sensor is the place to start looking.

I have never heard the 928 make any noise when the gas cap was removed.

Nicole

No seal on the gas cap. It confuses the smog testers every time, but my car always passes with flying colors.

JET951

928 does have a seal inside the "gas" cap , 928 201 275 03 , we replace them quite often , as we see them missing

Bertrand Daoust

No seal on the cap itself.
There's one on the fuel tank neck.

https://rennlist.com/forums/928-foru...er-gasket.html

Koenig-Specials 928

Same here in Ontario, Canada. The Testers usually try for about 5 minutes to figure out/get it to fit their adapter and then dismiss it by using one of their caps to generate the result they need to pass the cap test.

joejoe

Early 944's will release pressure when cap in taken off.

VegasGnome

The gas cap on my '85 has a seal ring--part #928 201 275 03. Two years ago the technician here in Vegas failed my car due to deterioration of this ring. I purchased a new one from 928Int'l and passed the re-inspection.

JET951

The seal within the cap ( 928 201 275 03) needs to be held in place with a water based adhesive ( just a smear ) to affix the seal within the cap , because they are prone to just falling out .

Note } if normal hydrocarbon base adhesive used , then the fuel " gas USA speak " or premium unleaded petrol " Australia speak" will just dissolve from the fuel vapours / liquid