American Motors and its French compatriot, Regie Nationale des Usines Renault , are lighting a fire under the Fuego in a drive to speed up sales. ''We're reintroducingm the Fuego,'' asserts J. C. Bird, head of AMC in New England. The problem has been the high success of the Alliance, a Renault-developed car now built in Kenosha, Wis., which has taken the spotlight away from the Renault's French-built cars: Le Car, the 18i, and the Fuego.
Renault has always had trouble moving its front-drive cars on the United States sales chart, mainly because it has never got across its message, or its cars, to American car buyers. Its linkup with AMC was a good move, even though it has cost the nationalized French carmaker about $450 million for a 46 percent stake in the US market.
The Alliance, adapted from the Renault R-9 to meet US road and buyer conditions, is moving ahead smartly - so well, in fact, that the French-American duo will add the hatchback Encore to the lineup in the fall, to be followed by more variations on the Alliance theme in the future.
AMC will also introduce a new generation of Jeep Cherokees and Wagoneers in the fall.
Among the casualties, it will drop the Renault 18i sedan, a poor performer partly because of problems with the 1981 car, and sell the 18i wagon with an Alliance nameplate. A 4-wheel-drive Alliance model will replace the AMC Eagle after 1984.
Ultimately, AMC will sell only Renault-developed cars, plus its own Jeep line.
The relaunched Fuego is a streamlined, sporty vehicle with a 96.1-inch wheelbase and 1.6-liter, fuel-injected, 4-cylinder engine, with or without a turbocharger. The base Fuego price starts at $8,695, while the turbocharged Fuego lists at $11,095, plus options.
Both the Fuego and 18i are variations of the same basic car, the Fuego being the more sporty version.
Neither the 18i nor the Fuego are bad cars to drive, but somehow the French carmaker fails to make the best use of the interior decor. As someone said on entering the turbocharged Fuego: ''Ugh! Look at thatm inside color'' - an unpleasant shade of light brown. And then there are those difficult door handles on the Fuego, which are hidden on the side of the doors where reaching in to open the car can be a nail-breaker at best.
An innovative keyless-entry system on the turbo (a $525 option) includes a tiny transmitter on the key chain. By pointing it to a small rectangular receiver on the dashboard, the doors either lock or unlock. It's an expensive toy, however.
Legroom in both the 18i and Fuego is good, both front and rear, but not the headroom.
What you dom have to get used to are the controls in French cars. The light switch, for example, requires a twist of the left-hand stalk. Some years ago the turn-signal stalk was on the right of the steering post, when everyone else had it on the left. No more, however. The steering wheel cuts through the upper part of the speedometer.
Even so, the Renault Fuego gives quite a good account of itself on the road, although the turbo boost doesn't show up till the engine gets up to 3,000 r.p.m. or thereabouts. A question: Why is the boost gauge located near the floor, where the driver has to look away from the road to see it?
In handling, the Fuego rates a high grade. The ride is sporty; that is, firm. Electric window switches are on the door and awkward to activate.
Where the Fuego shines is its mileage on the road. I got in the middle 20s, which, for a sports-minded turbo car, seems good indeed.
One point you can never forget about the Fuego: Its French accent really shows.