Engine Performance 2: Chapter 1: Fuel-Injection System Diagnosis and Service

Pressure-drop balance test

Most manufacturers recommend that the pressures be within about 1.5 psi of each other for satisfactory engine performance

Injectors should be tested for resistance and should read?

.3 to ,4 ohms

TBI equipped vehicle after one minute at a normal pressure holding capabilities is what?

10% or 10 minutes

Peak- and hold type

2 to 4 ohms

Hand operated vacuum should have how much in. Hg

20 in. HG

Typical port fuel injection fires fuel where

3 in from the intake manifold

Most port fuel-injected engines should be able to supply how much fuel pressure?

35 to 45 PSI

Testing the fuel injector tested for pulse

A noid light is designed to electrically replace the injector in the circuit and to flash if the injector circuit is working

Fuel injectors can be tested using ______.

All of the above

If the throttle plate needs to be cleaned, what symptoms will be present regarding the operation of the engine?

All of the above

Fuel injection service is being discussed. Technician A says that the throttle plate(s) should be cleaned. Technician B says that the fuel rail should be cleaned. Which technician is correct?

Both Technicians A and B

The fuel pressure drops rapidly when the engine is turned off. Technician A sats that one or more injectors could be leaking. Technician B says that a defective check valve in the fuel pump could be the cause. Which technician is correct?

Both Technicians A and B

In a typical port fuel-injection system, which injectors are most subject to becoming restricted?

Either A or C

What component pules the fuel injectors on most vehicles?

Electronic control unit (computer)

Saturated switch type

Have 12 to 16 OHMS

Injector voltage drop

Injector and measure the voltage drop across the windings as current is flowing

Injectors are tested?

Injectors are tested for proper resistance, voltage drop, pressure drop and on a DSO for proper waveform using voltage and current

Throttle-body fuel-injection system that use what type of injector driver?

Peak and hold

Port fuel-injection systems generally use what type of injector driver?

Saturated switch

The vacuum hose from the fuel pressure regulator was removed from the regulator and gasoline dripped out of the hose. Technician A says that this is normal and everything is okay. Technician B says that one or more of the injectors may be defective, causing the fuel to get into the hose. Which technician is correct?

Technician B only

Resistance check on fuel-injection

They should all have the same resistance

Port fuel-injection pressure regulator diagnosis

This reduces the pressure exerted on the diaphragm and results in a lower, about 10 PSI, fuel pressure applied to the injector