First post of many to come I am sure. I'm having a poor mpg issue with my '78 300cd and just noticed that when I remove the return line at the filter housing, fuel squirts out of the connection at the housing when I pump with the primer and if the car is running.

Now how is the fuel in the return line supposed to get returned if there is pressure going in the other direction?

I have the old style filter housing if that makes any difference.

To reiterate, there is fuel flowing into my return line from the filter.

Thanks