Question

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

Answer 1

Answer:

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

Answer 2

A should be the correct answer