Such a system may also divert excess fuel pressure from the pump back to the tank.

It measures the difference in fuel pressure taken from two locations within the regulator itself.

He was dominant in the 1992 race, leading 160 of 189 laps, when his car suddenly lost fuel pressure and drifted to a stop.

The injectors are held open by the fuel pressure.

But Stewart, despite an apparent problem with his fuel pressure, was ready for them.

The two indicators on top reported fuel pressure and fuel quantity.

"The fuel pressure went down to nothing twice, and it came back up," Waltrip said.

The intake is only slightly wet, and typical fuel pressure runs between 40-60 psi.

Andretti dominated the race a year later, leading 160 laps, until his car lost fuel pressure.

Michael Andretti had led 160 of the first 189 laps in that race before he lost fuel pressure.