Chicago's City Council erupted in pandemonium today when Mayor Harold Washington, lacking the votes to elect his supporters to council posts, adjourned his first council meeting after five seconds and walked out while the audience bellowed in shock.

Then, as the predominantly black crowd of 600 protested, the mayor's opponents reconvened the session, ramming through new rules and establishing new committees to limit Washington's power and that of the black and independent white aldermen who support him.

From his fifth-floor office, Washington attacked the rump session as "an illegal, non-binding and illegitimate meeting." His council supporters said they would take the issue to court and were confident of winning.

Meanwhile, three floors below, in the semicircular council chambers, with spectators shouting and one voice pleading for compromise, council President Edward (Fast Eddie) Vrdolyak and his 28 followers passed their package of measures on unanimous votes.

Afterward, Vrdolyak, who is Cook County Democratic chairman, said, "In 12 years on the council, I have never, ever seen a mayor turn and run."

The wild day at City Hall is one more episode in the tangled fight for power between the white-dominated Old Guard that has run Chicago for 50 years and the coalition of blacks, Hispanics, and liberal whites that elected Washington the first black mayor of the nation's second-largest city.

Alderman Martin Oberman, an independent, said the mayor adjourned his first meeting because, "we weren't ready."

"Vrdolyak last week took advantage of racial fears among some aldermen and the fact that a new administration is coming in," Oberman charged. "He put together a majority of votes. The new rules passed by the rump session . . . tie the hands of the executive branch."

The Vrdolyak-led majority, ignoring the fury of the crowd which had given Washington a standing ovation when he entered a few minutes earlier, set up 29 council committees and named blacks to head three of them. The old council had 20 committees.

Black Alderman Eugene Sawyer, named president pro tem by the white majority, said he would refuse to serve.

"Their meeting was illegal," Sawyer said.

Grayson Mitchell, Washington's press secretary, said the extra committees would add $500,000 to city costs as Chicago faces a massive deficit.

Washington had sought to institute rules that would allow him greater executive leverage and curb the power of Vrdolyak and other aldermen who had supported his Republican opponent during the recent election or had sat on their hands and refused to work for him.

The majority set another council meeting for Friday. But Washington supporters said they had no intention of attending.

Since his election April 12, Washington has trumpeted reform, vowing to dismantle the Democratic machine that has run Chicago for half a century. He attacked the machine again at his inaugural last Friday.

Washington's election drew international attention because of the racial overtones of the campaign with Republican Bernard E. Epton and because Chicago long has been considered the most racially divided northern city in the country.

His victory, based almost completely on a massive black vote, has been seen by black leaders across America as crucial toward fulfilling political aspirations of blacks increasingly unhappy with the Democratic Party.

The Washington coalition has talked bluntly about the need to bring the benefits of victory to voters who have felt ignored. At the same time, attempts were being made at negotiating with the machine.

Today, with pressure mounting, Washington telephoned Vrdolyak, who was in a meeting. By the time Vrdolyak returned the call, only 30 minutes remained before the mayor's first appearance as presiding officer. Washington said it was too late.

The divisive episode threw cold water on hopes that the two camps had found ways to accommodate their differences.

After the session ended today, the aldermen, all Democrats, clustered throughout the building, with each other and with reporters, to explain their sides of the dispute. Alderman Roman Pucinski, who opposed Washington during the election and today seconded all the Vrdolyak measures, seemed only slightly fazed by the drama.

"So now we sit down and work it out. It's obvious they weren't ready--they didn't have their ducks lined up. But we have to work it out together. We need each other."