Fuel sender leak or gas tank leak?

[JFP in PA]

Originally Posted by 78F350

JFP, I've come across a couple bad charcoal canisters recently. Would that be a likely cause of this? Is there a troubleshooting procedure for the evap system for someone like this without a Durametric or advanced test equipment?

Probably age more than anything else. When gas evaporates, it leaves behind a varnish like material that builds up over time, blocking lines and locking up the control valves. Diagnostic's are simple: are the lines clear and do the valves function.





1 - EVAP canister purge valve

2 - EVAP canister

3 - Purge air

4 - Tank

5 - Pressure sensor

6 - Shutoff valve

7 - Operating purge valve

8 - To intake manifold

9 - Vacuum control valve