In 1989 Fabi drove the No. 8 Quaker State March 89P-Porsche Indy V8. The engine and team began to compete regularly for wins with Fabi qualifying on pole at the Budweiser/G.I. Joe's 200 at Portland International Raceway and the Red Roof Inns 200 at Mid-Ohio Sports Car Course where he led for 71 of 84 laps to get what would be his last Indy car victory. The engine also began to be competitive on the ovals, as highlighted by a second at the Marlboro 500 at Michigan International Speedway and a third at the Pocono 500 at Pocono International Raceway. At the Indianapolis 500 Fabi qualified thirteenth and again finished thirtieth after retiring due to ignition problems after 23 laps. After his Mid-Ohio victory Fabi moved into third place in points. At the final two races of the season, the Firestone Indy 225 at Pennsylvania International Raceway and the Champion Spark Plug 300K at Laguna Seca Raceway, Fabi retired due to handling issues at Nazareth and a crash at Laguna Seca. At the end of the season he was fourth with 141 points.