The near collapse of a showcase U.S.-Chinese business producing Jeeps here has brought to light problems afflicting a large number of American firms that are investing in China.

Most involved business executives will not publicly air their complaints for fear that the Chinese would retaliate and restrict their dealings here. But Don St. Pierre of the American Motors Corp., president of a joint U.S.-Chinese corporation, said his problems have become so severe that his fledgling Jeep venture will have to shut down for about two months starting next month.

Senior Chinese officials say China is keeping its door open to foreign trade and investment. But a Chinese foreign-exchange shortage, which is St. Pierre's main problem, has cast a chill over much foreign business activity here.

St. Pierre, who returned to the United States for consultations this week, said in an interview here Wednesday that he is "still confident" that a solution to his problems can be worked out. But he said the Chinese were not keeping their part of an arrangement, whereby they were to provide millions of dollars in foreign exchange. The foreign exchange is to be used to import kits of American-made parts for Cherokee-type Jeeps and to begin building an industrial base from which parts can be produced in China.

What makes the $51 million Beijing Jeep Corp. operation especially sensitive is the showcase nature of the project. It was the first U.S. automotive joint venture and the first project of its size to be started here. When the project began in the fall, it looked like a model: Worker morale seemed to be rising; Vice President Bush visited the project.

But the days when executives such as St. Pierre could speak of the potential of a vast China market have faded. Overall, American trade with China has expanded over the past year. But many of the businesses investing here, particularly those with Chinese partners, face a formidable array of obstacles. These include not only the foreign-exchange shortage, but also rising costs and low productivity.

St. Pierre said worker productivity is not a problem thus far at his Beijing Jeep Corp. He said he is "pleasantly surprised" by what his 4,000 Chinese workers can do.

But living costs for foreign business executives are now among the highest in the world, according to a report prepared recently by George Lee, commercial attache at the U.S. Embassy here.

And a number of U.S. business executives interviewed here over the past year have indicated that they had painful problems in the early stages of the joint-venture process. Negotiating a joint-venture, they said, is no easy matter. And despite the years that it sometimes takes to negotiate, misunderstandings can arise long after the contract is signed. St. Pierre said that while American Motors felt it had an understanding with the Chinese on foreign exchange, "the Chinese may not have understood what we meant by the understanding."

The Beijing Jeep Corp. sells Cherokee Jeeps here for the equivalent of about $19,000. The big question now is how much of that can be converted into foreign exchange for further investment.

The new corporation has sold a total of only 464 Jeeps since September. The plan had been to produce 40,000 vehicles a year of the four-wheel drive jeep by 1991.

AMC, which owns nearly one-third of the joint-venture corporation, has invested $8 million in the deal, and another $8 million in blueprints, training and technological knowledge and expertise.

St. Pierre declined to say how much foreign exchange is needed to get operations going again after the projected shutdown of about two months. But one analyst estimated that the Jeep project will require $40 million a year in foreign exchange for the next several years.

St. Pierre said that under ideal conditions, the coporation would begin to earn enough foreign exchange to cover the costs and make the venture a foreign-exchange earner. The plan has been to compete with Japanese auto makers for the Asian market, which Japan now virtually controls.

But the recent battle over foreign exchange has strained relations between American Motors and Peking city authorities.

A U.S. official here said that while the total number of joint ventures involving American businesses has increased to more than 140, the rate of contract signing has slowed down.

Chinese foreign-exchange problems stem from an indiscriminate surge in nonessential imports that began in 1984. China depends heavily on oil exports, but oil prices have been falling. Nonetheless, executives said China still possesses foreign-exchange reserves that are more than sufficient to allow it to maintain essential imports.

In a recent speech delivered in Hong Kong, Roger Sullivan, the president-elect of the National Council for U.S.-China trade, argued that leaving joint ventures aside, prospects for trade with China are good, and likely to increase. U.S.-China trade reached more than $8 billion last year. U.S.-China joint ventures, are valued at a total of more than $1.4 billion.

The largest joint ventures are Occidental Petroleum's Pingshuo coal mine and Arco's Hainan Island natural-gas pipeline, valued at $175 million and $170 million, respectively, according to a recent U.S. Embassy report. But most U.S. investors have been cautious. About 60 percent of all U.S.-China joint ventures involve U.S. investments of less than $10 million.

Sullivan said one main reason companies were limiting their investments in China was restrictions placed on access to China's domestic markets. When a company is allowed into the market, it can generate foreign exchange for itself only by exporting its products from China. But exporting is made difficult, Sullivan said, because the costs of production in China, contrary to conventional wisdom, are not necessarily lower than elsewhere in the world.

Sullivan cited as one example the Nike footwear venture in China. He said Nike is producing shoes in China that are more expensive than the ones that it makes in Maine.

Most business executives agree that China's crackdown on foreign-exchange spending does not go as far as the so-called readjustment of 1980-82, when China canceled or postponed many major projects; most say that the Chinese are not breaking contracts. But the foreign-exchange squeeze and rising costs and taxes, said one leading U.S. business representative here, have pushed some companies to the point where "they may have to reassess their decision to have an operation based in China."