For weeks Ira M. Lechner's congressional campaign staff worked feverishly planning his four-day, 55-mile trek across Northern Virginia to be capped by a rally dramatizing his support for beleaguered federal workers.

Unfortunately, most of the 100 people who turned out for the Sept. 26 rally at the Office of Personnel Management were students and senior citizens -- not members of the 10th District's huge population of federal workers whose votes Lechner, a Democrat, is ardently courting. The reason: Lechner's staff had neglected to remind the leaders of federal unions to mobilize their members.

In retrospect, Donald S. Beyer Jr., the campaign manager, acknowledges the oversight. "Certainly I wish I'd made a bigger effort and asked the staff to invite everybody," said Beyer, a 32-year-old Falls Church Volvo dealer who has never before worked in a campaign.

Although Beyer says the campaign plans to hold a major union rally the weekend before the Nov. 2 election, Lechner's own advisers say last week's event illustrates the organizational problems the 48-year-old former Arlington delegate faces in his uphill battle to unseat the well-organized and better financed freshman Republican, Rep. Frank R. Wolf.

Those problems, they say, include high turnover -- Beyer is Lechner's fourth campaign manager in six months -- inexperienced staff, some of whom are recent college graduates new to Northern Virginia, and excessive involvement by Lechner in campaign details.

The candidate says he is pleased with his campaign. "This is the best effort and the best staff I've ever assembled," said Lechner, a Washington labor lawyer and outspoken supporter of causes considered liberal in conservative Virginia.

"I make no apologies for my organization," said Lechner, vice chairman of the state Democratic Party. "You just can't do everything as well as an incumbent. But the issues and the enthusiasm are on our side and in my 22 years in politics I've never sensed as much positive feeling for the Democratic Party. I think the positive side should be told as well as someone's missed phone call."

As evidence, Lechner points to the 2,000 volunteers working in his campaign, to his fully staffed phone banks and to the $235,000 he has raised so far, a figure state party officials say exceeds Virginia's other congressional challengers.

"That's more than Joe Fisher raised at this point in 1980 and he was a three-term incumbent running in a presidential year," he said, referring to former representative Joseph L. Fisher whom Wolf, a conservative lawyer-lobbyist from Vienna, narrowly defeated in l980.

However, several Democratic leaders say Lechner, who lost bids for Virginia lieutenant governor in 1977 and 1981, has failed to overcome the lingering antipathy of some veteran party activists who say they dislike his liberal politics, aggressive tactics and sometimes brash personality.

"Nobody has made any attempt to bring me back," said Emilie Miller, former Fairfax County Democratic Party chairman with ties to monied Democrats. She said Lechner knocked her off the State Central Committee after she failed to support his 1981 bid for lieutenant governor.

Arlington State Sen. Edward M. Holland, one of Lechner's finance chairmen, said he is having difficulty raising money from Democrats who are traditionally big contributors. "I'm getting 'no' from most people who say they're supporting candidates in other races or they're just hesitant to give."

Initially, Lechner, who has strong union support, had said he hoped to raise $400,000. This week he revised that prediction and said he expects to raise more than $300,000 and won't begin political commercials until the last week in October.

"I'm concerned about the campaign," said one federal official close to the campaign who requested anonymity. "The walk was a good media ploy but he should have done it Labor Day. It's almost as though Ira's waiting to see the whites of their eyes, and he's only got five weeks left."

"Ira has gotten too bogged down in minutiae and spends too much time developing mailing lists when he should be out there galvanizing federal workers," the official added. "What he's got to do is be the candidate and let someone else run the campaign."

Beyer, who is also Lechner's finance chairman, acknowledges that the campaign has experienced organizational difficulties. "I'm a rookie and I don't pretend to have the depth of political judgment [others do]. The short answer is that yes, we've had problems . . . . We're still tightening and I hope we can do more of that in the next five weeks."

So far, Wolf has raised about $325,000 of his $475,000 goal, $37,000 of which represents contributions and services provided by affiliates of the national Republican Party.

"Frank Wolf is going to be hard to beat," said William Bischoff, acting director of the Virginia's Democratic Party, who ranks Lechner as one of the least likely victors among the state's Democratic congressional contenders.

"The 10th is not a seat we consider in jeopardy at all," echoed Rich Galen, a spokesman for the National Republican Congressional Committee.

Lechner has not gotten any money from the Democratic Congressional Campaign Committee, unlike his 8th District counterpart, former representative Herbert E. Harris II. Harris, locked in a race with Republican Rep. Stanford E. Parris that is considered a tossup, has received $5,000.

"Ira has done very well in terms of fund-raising," said Evan Zeppos, spokesman for the committee. "We haven't given Ira any money so far because of our limited financial resources."

Although he trails in fund-raising, some party leaders say they believe a strong Democratic trend could help Lechner, who is casting the race as a referendum on Wolf's support for the Reagan administration's social and economic policies.

"Ira is a hell of a candidate and he's got an awfully good set of issues," said Jerry Klepner, political director of the National Treasury Employees Union. "A lot of federal workers are very angry at Wolf and this administration. Our groups will be working very, very hard for Ira."

Others are less sanguine about Lechner's chances against an incumbent with formidable advantages in a district where Republicans have made substantial recent gains.

Wolf's campaign is being run by Ed DeBolt, one of the state's premier political consultants, who engineered Wolf's 1980 victory and has advised the winning Republican campaigns of former Gov. John N. Dalton and Sen. John W. Warner. From his office near the Arlington Courthouse, DeBolt commands a seasoned team that has honed its political skills during Wolf's three previous congressional campaigns and through long experience in local Republican politics. Wolf enjoys wide popularity within his own party and, Democrats grudgingly admit, with some of them as well.

"Ira seems to be strong in Arlington and he does have a good phone bank operation," said Sen. Holland. "But the history of this district is that voters usually don't turn people out after one term without a really good reason and I don't think Frank Wolf has messed up badly enough to be turned out."

There are also signs Lechner may have failed to win back some party regulars. "I just don't see much excitement about this race," said one prominent Democrat. "I think a lot of experienced people are working for [Arlington County Board candidate] Mary Margaret Whipple and [U.S. Senate nominee Richard J.] Davis."

Emilie Miller, for example, is raising money for Del. Norman Sisisky, a Democratic congressional candidate from Petersburg. "I've offered to help a couple of times with fund-raisiers, but Ira has never personally called me and nobdy from his staff has. I guess they've just written me off," she said.

"Ira has the strengths and weaknesses of someone whose politics tend to be ideological," said George Gillam, a veteran Democratic Party activist from Charlottesville. "The people who agree with him are very passionate. The flip side of that coin is that having been out front on a lot of issues, you make a lot of enemies."

Beyer says he is sensitive to Lechner's intraparty problems and is trying hard to woo the alienated. "I'm beginning to get positive feedback from the local Democratic committees," he said. "If we made any mistake it's not asking people to help who wanted to."