A populist coalition that many in conservative Virginia thought was extinct boosted lieutenant governor hopeful Ira M. Lechner to a surprisingly strong showing in statewide Democratic delegate-selection meetings this weekend.

Lechner, a former Arlington legislator who lost a primary bid for the same nomination four years ago, stunned party leaders and even many fellow liberals this time by relying on activists from labor unions and consumer, feminist and teacher groups.

These were the same groups that four years ago gave liberal former lieutenant governor Henry Howell his surprise gubernatorial primary victory over Andrew Miller, a popular and conservative former state attorney general.

"Ira did some of what we did -- he galvanized the activists," said Paul Goldman, who managed Howell's 1977 upset. "He proved again that liberal Democrats are still a constituency in Virginia and if you can turn them on, they can come out and win."

While both sides claimed victory today -- about 25 percent of the party's convention delegates remain to be chosen Monday night -- it was clear that underdog Lechner had effectively upstaged reputed front-runner Richard J. Davis.

As of tonight, official figures released from state party headquarters here gave Davis, former state party chairman and Portsmouth mayor, a slight edge with 1,052 votes to Lechner's 997. State Sen. Dudley J. Emick of Fincastle was a distant third with 140 and 326 were uncommitted. But Lechner was still claiming victory based on his own figures, which-showed him ahead by 1,098 to Davis' 877.

Whoever is nominally ahead, the two camps agree that the contest will not be decided until next month's party nominating convention in Virginia Beach.

The same is true of the hotly contested attorney generalhs nomination, where state Dels. Gerald Baliles of Richmond and Erwin S. (Shad) Solomon of Bath County finished nearly deadlocked yesterday. Baliles won 868 delegates to 836 for Solomon, with a huge volume of 816 uncommitteds, according to state party figures.

Many Davis supporters said yesterday's real loser may be a man who ran uncontested -- Lt. Gov. Charles S. Robb, the party's certain gubernatorial nominee. Robb's supporters had assumed that Davis would be Robb's ticket partner. While split on some issues, the two men are firmly in the party's moderate-to-conservative wing, where Lechner has few backers.

Robb until now has maintained official neutrality, although many of his supporters have worked hard for both Davis and Baliles. "We've got to live with whoever gets it," said Robb spokesman George Stoddart today, adding that Robb will publicly maintain his neutral stance.

Privately, Robb's supporters are expected to turn up the pressure on Emick's delegates and on the uncommitteds to switch to Davis.

"Ira's a very weak link in the Democratic ticket," said University of Virginia political scientist Larry Sabato. "He's just too liberal to win a statewide race and to link Robb with Ira would just dovetail to [State Attorney General] Marshall Coleman's benefit." Coleman is Robb's certain GOP opponent for governor.

Davis campaign manager Robert Watson echoed the same theme: "I just hope Chuck's people realize that a Robb-Lechner ticket means Chuck Robb will be defeated on the day of the convention, only the results won't be in until November."

If he steps in publicly or privately, however, Robb runs the risk of alienating large groups of Lechner supporters. "Chuck Robb's crazy if he thinks he can win without carrying Northern Virginia and to win Northern Virginia he needs Ira Lechner's supporters if not Ira Lechner himself," said Arlington Del. Warren G. Stambaugh, a Lechner supporter.

Lechner won big in Northern Virginia yesterday, grabbing more than 600 delegates to fewer than 100 for Davis. He also surprised Davis by making inroads in the Tidewater area, Davis' home turf, capturing 78 of Newport News' 100 delegates and 82 of Hampton's 84 with the help of members of the United Steelworkers' union and other area labor groups.

"When you're the front-runner, no one believes you when you say you're in trouble," Watson said. Watson said he suspected several weeks ago that Lechner was gaining strength but had trouble convincing local Davis supporters of the threat. "Every time Ira left town I knew he'd been there doing something but I didn't know what."

Lechner conceded today he would not win a majority of the 900 delegates still to be chosen at meetings Monday night. But he predicted that the contest probably will be decided on the convention floor. He plans a series of challenges to the credentials of delegates from Davis strongholds such as Portsmouth, where Lechner claims there were balloting irregularities.

Win or lose, liberals believe the strength of Lechner's challenge has served notice on Democratic leaders that they cannot ignore the party's still-formidable liberal constituency.

"The party establishment got greedy," said Goldman. "They wanted not only Robb, but Davis and Balieles as well. They tried to ram it down everybody's throats, but people won't but it."