EUI Electronic Unit Injectors

Question 1

What actuates the Injector on an EUI

Answer 1

An overhead cam directly actuates the EUI through a rocker arm. Also uses a dedicated camshaft lobe for the injector and is generally the widest lobe to distribute the load

Question 2

What is a EUI

Answer 2

An injector that meters, pressurizes and injects fuel directly into the combustion chamber.

Question 3

What is the fuel pressure of a EUI

Answer 3

Up to 38,000 psi

Question 4

Is it true that high spray in pressure in a EUI are dependant on engine speed?

Answer 4

Cam-plunger velocities must be at their fastest to achieve the highest spray in pressures. Unless it’s the Delphi E3 EUI which can vary injection pressure over all speeds using a secondary electrically operated control valve

Question 5

Do EUI’s have the least ankunt of injection delay?

Answer 5

Yes because they have no pushrod to bend or injector lines to swell or delivery valves to lift.

Question 6

How many spray holes do EUI’s have?

Answer 6

Between 5-13 spray holes.

Question 7

Are EUI’s adjustment free?

Answer 7

Pretty much

Question 8

What die the spring loaded plunger and barrel do In a EUI?

Answer 8

Pressurizes fuel inside the injector

Question 9

What does the poppet valve do in an EUI?
(Spill control valve)

Answer 9

Regulates the buildup of pressure inside the injector

Question 10

What does the electric solenoid or cartridge valve do in an EUI?

Answer 10

Controls movement of the poppet valve

Question 11

What does the fuel inlet and return passegway do in an EUI?

Answer 11

The inlet is supplied low pressure fuel from the transfer pump
The return permits fuel to flow back to the supply tank to remove heat from injectors

Question 12

What does the nozzle valve do in an EUI?

Answer 12

Opens at 3500-5000 psi
Atomizes fuel
Crisp beginning and end of injection cycle

Question 13

First gen EUI’s use what time control BOI and EOI

Answer 13

A single electrically controlled poppet or spill control valve

Question 14

Dirt cause what in the injector

Answer 14

Spill control valve scoring, damage and black or gray smoke, high fuel consumption and low power

Question 15

Water does what

Answer 15

Blows injector tip to smithereens

Question 16

What us cyl cutout test

Answer 16

Cuts out cylinders to identify which injectors are bad

Question 17

Cyl contribution test is what?(cyl balance)

Answer 17

Compares cyl pressures to one another and measures contribution of each cylinder

Question 18

Injection occurs when?

Answer 18

When the camshaft lobe is on the outer base circle amd the spill control valve solenoid is energized

Question 19

When the poppet valve closes (spill control valve) what happens

Answer 19

Slight change in resistance or voltage drop

Resistance increases- voltage drop increases

Question 20

When do you replace injector cups?

Answer 20

When reconditioning the head or when fuel is found in the coolant

Question 21

The atomization of fuel in an EUI is compared to what?

Answer 21

Fog

Question 22

PWM controls what

Answer 22

How long injector stays on

Question 23

If you have low current what’s it mean

Answer 23

Open winding, disconnected wiring

Question 24

If yiu have high current what’s it mean

Answer 24

Shorted or grounded wiring