EVAP Leak Sources

[DamienH]

2005 Z4 E85 w/ 2.5i


This car has had an issue with the p0442 'Minor Evap Leak' for around 6-8 months now. I'm completely out of educated guesses on what it'll take to fix it. Literally, to no exaggeration, the entire fuel & evap systems have been re-built. All new parts. All strictly OEM.


New fuel tank. New fuel pump. New main fuel hose gaskets. New fuel pressure regulator & filter. Injectors cleaned. New DMTL pump. New Gas cap. New charcoal vapor canister. New purge valve. New intake boots. New MAF.


Both fuel & evap systems pressure+smoke tested AND vacuum tested on multiple occasions. No discernable faults.


The goddamn car is still convinced that it has a fuel leak somewhere. Honestly, what else am I supposed to look at to get rid of this code?


Is there a way to change the computer to accept different criteria and trick it into thinking there's no error? I cannot register the goddamn car until this issue is sorted and I'm done spending money on new parts and tests....

[Clearancediver]

Strictly left field answer here…. Have you cleaned all the electrical connections? Dirty connections lead to increased resistance in a circuit and in one instance I know of.. creates a fault. I’d use electrical cleaner on every connection and see if that does the trick.


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[clarkitect]

Check for a broken wire too.

[BimmerBreaker]

You can code the EVAP/DMTL system out but in California you are not likely to pass smog like that

All the parts seem to have been replaced, but I do wonder if they are smoke testing it correctly. It should be smoke tested with the system active, otherwise, you are only smoke testing some of the system.

[pokeybritches]

Is there a way to change the computer to accept different criteria and trick it into thinking there's no error?

Yes, this is possible but carries some risk, especially in California. Success depends on how thorough the inspection is and whether the CVN is checked.