One of the best ways to find a vacuum leak on a speed-density fuel-injection system is to read the intake air controller (LAC) count, or percentage, with a scan

tool. Normal IAC percentage is usually 15 to 25. A reading of less than indicates vacuum leak.

O A. 5

OB. 10

O C. 25

O D. 15

The correct option is A:

A) 5

Explanation:

One of the best way to know about the vacuum leak on a speed-density fuel injection is to look at IAC count or percentage. A reading less than 5 would indicate a vacuum leak. The extra air from the leak will result in:

Increase of Idle speed MAP sensor interprets it as an additional load on the engine Injector pulse width increases IAC count decreases, trying to reduce engine speed to a previously set value Air-fuel mixture remains the same