EFI Service Flashcards
True or False: There is no fuel filter on return-type fuel systems
False! There must be a filter as gasoline runs through the entire system - debris must be caught by the filter before returning to the tank
How often should a fuel filter in a return-type fuel system be replaced?
replace at ~40,000km
-restricted filters can lead to stalling and lack of power
What is the procedure for removing a fuel filter on a return-type system?
1) Locate filter (can be under the car near the fuel tank or in the engine bay near the firewall)
2) wear eye & hand protection - have a fire extinguisher nearby
3)depressurize the fuel system before disconnecting the filter
4) remove either: fuel pump fuse or relay or pump connector at top of fuel tank
5) place a drain pan underneath
6) wrap fitting with a cloth (when you loosen filter lines, fuel will spray out for a few seconds - *
Is there a filter on a return-less system?
No!
Only the in-tank fuel pump filter is used, and no replacement is needed.
Dirty throttle bodies can cause:
Rough idle and stalling
What are the pros and cons of removing the throttle body for cleaning?
Pros: on some engines it is easy to remove and leads to more thorough cleaning
Cons: sometimes leaving it is best as you will require a new gasket
Throttle body cleaning should not be needed on vehicles with less than _____ kms
100,000kms
What is a PCV Valve?
Positive Crankcase Ventilation
It’s a system that removes blow-by gases (unburned fuel, oil vapours, and combustion byproducts) from the crankcase and recirculates them into the intake manifold to be burned again
Why do throttle plates get dirty?
Exhaust gasses recirculated from the PCV valve (Positive Crankcase Ventilation) to the air intake reach the intake manifold, clinging to the throttle plate
True or false: integrity of the intake air path between the air filter housing and where the intake manifold bolts to the cylinder head is critical
TRUE!!
How can you check for the integrity of Air intake system?
Using a smoke machine to check for leaks
What is the path of the air intake system?
START:
Air filter housing
Intake air hose
Throttle body
Intake manifold
Final Destination: Cylinder head
Where is cylinder #1 located on an engine?
At the front (accessory drive belt end of the engine)
What is a “bank” in an engine?
A bank is one side of the engine on a V-type engine
-OR-
One half of the engine on 6 cylinder inline engine
What does “Bank 2 Sensor 1” mean?
This oxygen sensor is located to read Bank 2 (opposite of cylinder 1), and is furthest upstream and close to the engine.
What does “Bank 1, Sensor 2” mean?
This oxygen sensor is located to read Bank 1 (Cylinder 1), and is further downstream to the engine.
(this can either be the last sensor in the line, or there can be more further down)
The _____ of engine is opposite of where the engine and transmission meet
Front
What is the difference between GDI and port injection?
GDI (gasoline direct injection) engines have fuel injectors inside the cylinder, rather than port injection which is behind the intake valve
Why are GDI engines susceptible to carbon deposits building up on the BACK of the intake valves?
-Blow-by gases entering the intake manifold via the PCV (Positive Crankcase Ventilation)
-AND-
Fuel injectors are not behind the intake valve which would normally wash the valves clean as new fuel is introduced
On GDI engines, how can carbon build up on intake valves be corrected? (3)
Cleaning!
-Chemical cleaning
-Walnut shell blasting
-remove the cylinder head from the engine to remove and clean valves
On GDI engines, what occurs as a result of carbon buildup on intake valves?
Hampered air intake breathing (volumetric efficiency)
-Leads to rough running, poor performance, etc.
(some are more prone to this than others)
Why are fuel injector tips prone to deposit build up in a GDI engine?
Injectors are in the combustion chamber
