ENGINE CONTROLS 1F–303
DAEWOO M-150 BL2
BACKFIRE
Definition: Fuel ignites in the intake manifold, or in the
exhaust system, making a loud popping noise.Important: Before diagnosing the symptom, check ser-
vice bulletins for updates.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Inspect for crossed or crossfiring ignition wires.
2. Check the ignition system output voltage for all
cylinders using a spark tester.
3. Inspect the spark plugs for excessive wear,
burned electrodes, improper gap, or heavy
deposits.
Is the problem found?
–
Go to Step 3Go to Step 4
3
Repair or replace any ignition system components
as needed.
Is the repair complete?
–
System OK
–
4
1. Check the fuel system operation.
2. Check the fuel injectors by performing an injector
diagnosis.
Is the problem found?
–
Go to Step 5Go to Step 6
5
Repair or replace any fuel system components as
needed.
Is the repair complete?
–
System OK
–
6
1. Inspect the Electric Exhaust Gas Recirculation
(EEGR) gasket for a leak or a loose fit.
2. Check the EEGR valve for proper operation.
3. Inspect the intake manifold and the exhaust
manifold for a casting flash.
Is the problem found?
–
Go to Step 7Go to Step 8
7Repair or replace any components as needed.
Is the repair complete?–System OK–
8
1. Inspect the timing belt for proper installation and
tension.
2. Check the engine compression.
3. Inspect the intake manifold gasket and the
exhaust manifold gasket for leaks.
4. Check for sticking or leaking valves.
5. Repair or replace any components as needed.
Are all checks and corrections complete?
–
System OK
–
4F–4 ANTILOCK BRAKE SYSTEM
DAEWOO M-150 BL2
feed back to the master cylinder and brake pedal.
D107E005
Return Pump Motor
The motor drives two pump elements through the ec-
centric wheel on its shaft.
Return Pump
Description: Each pump element consists of a fixed
displacement piston driven by an eccentric on the end of
the eccentric motor. It has two check valves (inlet and
outlet) and is fed with fluid by the low pressure accumu-
lator.
Operation:
Compression stroke: the pump is filled via the inlet ball
seat, then the motor eccentric rotates moving the piston
to displace the fluid. After the pressure build-up closes
the inlet valve the piston displacement increases the
pressure until the outlet ball opens. The outlet pressure
will continue to increase for the rest of the piston stroke.
Return Stroke: The piston retracts, forced by its spring,
as the motor eccentric returns to its low end position.
The pressure at the inlet side of the outlet ball then de-
creases due to the displaced volume and the pressure
difference across this ball holds it closed.
The pressure at the outlet side of the inlet ball seat,
which is set to open at a certain pressure level also de-
creases until this valve opens. With the outlet ball
closed, the pump is filled with additional fluid from the
low pressure accumulator.
The pressure will continue until a stall point is reached
and compression of the piston cannot generate enough
differential pressure anymore to open the outlet ball
seat.
D17E006A
Return Pump
Return Pump
Motor(0.12~0.16 in.)
EBCM (ELECTRONIC BRAKE
CONTROL MODULE)
Notice: There is no serviceable. The EBCM must be re-
placed as an assembly.
The EBCM is attached to the hydraulic unit in the engine
compartment. The controlling element of ABS is a mi-
croprocessor-based EBCM. Inputs to the system in-
clude the four wheel speed sensors, the stoplamp
switch, the ignition switch, and the unswitched battery
voltage. There is an output to a bi-directional serial data
link, located in pin M of the assembly line diagnostic link
(ALDL), for service diagnostic tools and assembly plat
testing.
The EBCM monitors the speed of each wheel. If any
wheel begins to approach lockup and the brake switch is
closed (brake pedal depressed), the EBCM controls the
dump valve to reduce brake pressure to the wheel ap-
proaching lockup. Once the wheel regains traction,
brake pressure is increased until the wheel again begins
to approach lockup. The cycle repeats until either the
vehicle comes to a stop, the brake pedal is released or
no wheels approach lockup.
Additionally, the EBCM monitors itself, each input (ex-
cept the serial data link), and each output for proper op-
eration. If it detects any system malfunction, the EBCM
will store a DTC in nonvolatile memory (DTCs will not
disappear if the battery is disconnected).
