360 Anti-Evap leak diagnosis

Are you looking for intake leaks or do you have a fault code for the evap system?

If you’re running the engine up to temperature, I don’t think I’d want fuel vapour drifting into the engine bay, but if you’re just doing intake smoke checks on a cold engine, that sounds relatively safe.

 

In theory, the only thing you would need to disconnect would be the purge solenoid valve electrical connectors and that would stop the vapours going into the intake. I assume there is some system which would vent the vapours to atmosphere if the pressure got too high in the tank.

Or do you think you have a leak in the evap system?

Image Unavailable, Please Login

 

Sorry.... just re-read the title...

 

How does plugging those hoses lead to a diagnosis?

 

Are you getting codes for an evap system leak... or are you more worried about the engine getting unmetered air from somewhere (affecting fuel ratios)?

I see there are some variations in the USA evap system (basically 1999 vs 2000 onwards). The later models have a pressure sensor on one of the tanks, allowing better fault detection. I assume the sensor is used when the vent/purge valves are in certain configurations.

 

This video answered most of my questions on the evap system:



The 360 doesn't have the diagnostic pump (the 430 does).

If you're not getting evap codes, then it's unlikely you have a leak.

 

Not likely. Motronic detects leaks far smaller than the engine will ever notice.

There is one reliable test for eveap leaks. A smoke machine.
9 times out of ten it is the seals at the roll over valves. Sometimes it is the electro vent valve at the cannister.