Driving this morning my check engine light was thrown so I stopped at advanced and they read a large evap leak. I have not been home yet to check the rave and evap system. Has anyvody else had this same problem or give me some advice in what I may need to change?

Thanks all

 

Tighten and or replace gas cap. There can be other problems, but this is the cheapest one to fix. There is also a small EVAP leak, the system tries to test to determine if there is a leak, and how many microns might be involved. Here are two pages from the Bosch manual, whole thing is a series of links in my signature. The size of detection (40 micron vs 20 micron) also depends on year of vehicle. Would help to know year of truck, and the code number they observed. Also - a human hair is about 100 microns in diameter on average, so finding a leak in the system under a truck, reclined in comfort on the gravel, with normal mud and oil coating, in sub freezing weather - might be fun.

 

I get this too at different times. Sometimes right after I put gas in and maybe don't put the gas cap on tight enough, or if I let my tank get close to empty.

 

I forgot to include that my truck is an 01 sorry bout that savannah. The guy at advanced didn't tell me the code number just that it was large evap leak. I will try the gas cap and see if that clears it...my luck it wont, lol. Thanks for the pdf im getting ready to check it out.

Thanks guys this gives me an idea where to start.

 

Have you done a smoke test yet? Either of you? Its pretty simple to do! Otherwise you could try the starting fluid spray and listen for your truck to rev up.

 

I haven't yet just because it has been so intermittent on mine. Only shows up about once every three or four months. And every time it does, tightening up the gas cap, or filling her up seem to do the trick

 

An evap leak is an entirely different thing from a vacuum leak, the starting fluid trick won't work on an evap leak. (smoke would if you introduced the smoke into the evap system rather than the intake manifold)

 

Yes this i know but the guy at advance with no training at all probably does not know the difference between the two. He did not even give the guy his fault code to fix the issue. Advance always say we sell a gas cap it will probably fix your problem.... they would love nothing more to sell you a gas cap.

 

Lol ain't that the truth, and it never helps being the guy who jumps up after the advance code reader is done and says thank god its not a mis fire.

I will get a smoke test done and find out where its coming from

 

Had the same problem on and off for months. Although the cap always seemed tight I got a new one (proper LR part, not a substitute) and haven't seen the code since. Cap seals don't last forever (and my Disco was two years younger than this one) and a cap is a lot cheaper than a smoke test and I would guess it would be the major suspect for a "Gross" leak. Just saying.......