Defense Secretary Caspar W. Weinberger said yesterday that he will visit Central America next month to discuss the situation with officials there and to watch the joint U.S.-Honduran military maneuvers.

"Normally I like to go where the troops are," he told a Pentagon news conference when asked to elaborate on the purpose of his trip, "and this is an important exercise in Honduras." He will visit Panama, Honduras and El Salvador Sept. 6-8.

He said he believes El Salvador's forces have made significant progress in combating the guerrillas there, thanks in part to U.S. training in small unit tactics.

"It is going very much better," he said of the Salvadoran government's military campaign. It appears "as if the training is beginning to take hold, and as if the morale and the leadership is improving." He said measures of progress include the number of engagements conducted by government troops against the guerrillas.

U.S. military leaders in the past have faulted their Salvadoran counterparts for favoring set-piece, large-scale operations featuring heavy artillery fire. U.S. training of the Salvadoran forces emphasizes tactics for pursuing guerrillas in the bush with small, fast, hard-hitting infantry units.

Another weakness of the Salvadoran army is that it is not trained or equipped to care for its wounded in the field, resulting in a high death rate. Weinberger said the current force of around 26 U.S. military medical specialists in El Salvador may be expanded, but that the number of military trainers there will not exceed 55.

In his news conference, Weinberger responded to the current horror stories about contractors overcharging the Pentagon for spare parts and went to considerable lengths to assure Congress and the public that corrective actions are being taken.

"We do feel a personal obligation to exert every effort to strengthen and straighten out the whole spare parts situation," he said, adding that remedial steps are "well under way." He said those steps include:

* Requiring bidders on the Air Force's fighter engine contract to guarantee that there will be competition in buying spare parts for the engines.

* Forbidding contractors to set their own prices on spare parts from now on.

* Demanding that contractors refund overcharges to the Pentagon on spare parts. "We got $84,000 from the claw hammer people and $76,000 from the diode people," he said.

* Conducting an audit of "all types of spare parts throughout every agency" in the Defense Department.

Weinberger also said "it's certainly a little startling" that the same Congress that demanded more competition in defense contracting is proposing to ban, in the fiscal 1984 defense procurement bill, bidding on contracts for M1 tank engines by companies other than the Avco Corp.

Asked for his reaction to Soviet president Yuri V. Andropov's statement that the Soviet Union would not be the first to use anti-satellite weapons in space, Weinberger replied: "Well, they're the ones who have them at the moment. So it isn't too much of a surprise."

The Soviets have been experimenting in space with a satellite that hunts down and then explodes near another satellite, apparently destroying it with shrapnel.

The United States is developing what Pentagon specialists consider more advanced systems, including one that collides with a target satellite after being launched from an F15 fighter. The Vought Corp. is expected to test this satellite killer soon.

In response to questions about the Pershing II missile, which the United States hopes to start deploying in West Germany this December, Weinberger said, "The missile is totally on schedule as far as its development is concerned, and it's ready for deployment."

He played down the significance of recent failures during the missile's flight tests, attributing them to the missile's complexity.

The nuclear-tipped Pershing II, he said, is "more essential now than it was" when it was planned in 1979 because "the Soviets have added an enormous number of SS20" intermediate missiles to their arsenal in Europe.