missing gas cap - what will it affect

[channer]

Hi all

this is for my winter beater 90 4runner. I failed my local emissions test early this week, and I notice I was missing my gas cap when I went to fill the tank tonite. The garage mentioned that they had to clean the filler neck because of rust & I think they forgot to put the gas cap back on... to perform the emissions test!!!! Filler neck looks clean!!!!

Does anyone know what a missing gas cap will affect (HC, COs NOX). I failed miserably on NOX

thanks... dave

 

[Gary Wells]

I do not know what emissions that would affect, but in Ca it is part of the functional and visual test. It must be on the car and it must seal.

 

[Googs]

Hi all

this is for my winter beater 90 4runner. I failed my local emissions test early this week, and I notice I was missing my gas cap when I went to fill the tank tonite. The garage mentioned that they had to clean the filler neck because of rust & I think they forgot to put the gas cap back on... to perform the emissions test!!!! Filler neck looks clean!!!!

Does anyone know what a missing gas cap will affect (HC, COs NOX). I failed miserably on NOX

thanks... dave

It will slightly affect all of them. I just had my car tested & the gas cap seal was bad. Put a new seal on & I had a small change in the numbers. If you're only failing NOX & it's bad, then there is something else wrong besides your cap.

 

[gofstbuick]

What are the rest of the numbers? If your failing NOx miserably, you need to address EGR, fuel control, Ignition, combustion chamber carbon build up, cooling system and cat. Probably in that order.