Delphi Automotive Systems, Troy, Mich., has made an additional $325 million contribution to its U.S. hourly defined benefit pension fund. This brings the total 1999 voluntary contributions to $1.2 billion. However, the $4.6 billion pension fund is still underfunded, according to SEC documents. As of Sept. 30, the long-term pension liability was $1.5 billion, SEC documents stated. This payment would bring that sum down to about $1.2 billion.