Evap System Test

Post by **MrAl** » 13 Jul 2017, 06:38

Hello again,

Thanks for the links and info and for fixing the link. Looks very interesting so i'll be doing some reading.

Also, thanks for confirming that the secondary air system air pump does NOT get involved in any pressure or vacuum test of the Evap system. I had worried a little about that because i replaced the air pump myself.

The Evap system tests look kind of complex. That's unfortunate.

Post by **abscate** » 13 Jul 2017, 08:52

The component tests are pretty simple - so once you know where everything is, its easy to figure out what isn't working.

Smoke tester is your friend for finding the tiny hole in a hose that can't be seen.

Post by **abscate** » 13 Jul 2017, 08:59

The system test the purge valve , tank and hose integrity, shutoff valve for operation but it only reports based on basic data from the tank pressure valve. If you read the gory details, the report of a large or small leak can come from a number of failures.

The best approach, once you get a code, is to

Test hoses with smoke
Test purge and shutoff either directly or replacing with good known parts.

***We should start a parts bank for having these from a PnP perhaps****

Post by **MrAl** » 13 Jul 2017, 10:21

Hi Steve,

Thanks for the extra info.

What did you mean though by 'start a parts bank' ?

Thanks again.

Post by **abscate** » 13 Jul 2017, 12:33

Fantasy of mine to have a stash of good parts from MVS that we can loan to people to hone in on diagnoses. Sort of like the tool loan program.

Post by **MrAl** » 16 Jul 2017, 07:41

Hi,

Oh yes sounds like a good idea. Might have to stock a lot fo parts for that though with so many cars.

This Evap test thing seems a bit excessive. I read it can detect the presence of two pinholes. Like that is going to cause the end of the Earth.