i've been trying to find out why my 90 civic DX (completely stock) is stalling while braking when there is 1/4 tank of gas or less. but thats besides the point. my question is, the red braided line coming from the back of the intake manifold (DPFI) that goes to the carbon canister, seems to have very low vacuum, if any at all, while the car is running...is this normal or should it have the same amount of vacuum as say the hose to the FPR?

 

Vac pressure is fine.
as for the stalling. Sounds like you need to do some tank cleaning.

 

i also know that the purge solenoid on the firewall is supposed to open (close, if speaking in electronic circuits) when the key is in 'on' position... i can pull vacuum thru the canister side hose, but it draws air from under the round cap on top of the solenoid, and i cant pull any vacuum thru the engine side hose. with the ignition off, i can barely pull vacuum either way. and one other thing, i can blow thru the vent line that goes back to the fuel tank, but cannot pull vacuum on it. does anyone know exactly how these valves and solenoids are supposed to flow?

 

i just changed the fuel pump and strainer less than a month ago, cleaned the tank while it was down. none of this started until i noticed the drain plug on the tank was slowly leaking and i pulled it, coated threads with teflon tape, and re-installed it. my guess is there is a venting problem and before, it was venting thru the drain plug