Buick Regal: Engine Cranks But Does Not Run
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
Circuit/System Description
This Engine Cranks but Does Not Run is an organized approach to identify a
condition which causes the
engine to crank but not start. This diagnostic directs the technician to the
appropriate system diagnosis.
Diagnostic Aids
Inspect for any of the conditions listed below:
- If equipped with a key type ignition system, a partially retracted or
folded over ignition key. When
attempting to start the engine, the mechanical portion of the vehicle key
must be locked in the
fully extended position with the fob parallel to the key. Leaving the key
partially retracted or
folded over when starting may interrupt transponder authentication and
result in an intermittent
no-start condition. In such instances, DTC B3055 may also be set. If an
intermittent no-start
complaint is received, it may be necessary to discuss with the customer
their starting habits and
verify they are locking the key in the fully extended position, fob parallel
to the key, before
starting.
- A crankshaft position sensor condition. When this condition is present,
the engine control module
(ECM) uses the camshaft position sensors to determine engine speed and
position. If the condition
exists in the signal circuit of the sensor, the engine will go into a limp
home mode after a hard
restart. The ECM then calculates engine speed from one of the camshaft
position sensors.
However, the engine will operate with a crankshaft position sensor condition
only if the ECM has
stored the learned reference position of the camshafts in memory.
- An in-tank fuel pump condition. The fuel pump control module controls
and monitors the
operation of the in-tank fuel pump. If the fuel pump control module detects
a fault, a DTC sets in
the fuel pump control module. The fuel pump control module will then send a
serial data message
to the engine control module (ECM) requesting the illumination of the
malfunction indicator lamp
(MIL).
- Insufficient fuel. Thoroughly inspect the fuel delivery system for
sufficient fuel volume to the fuel
injectors. Inspect the fuel supply components for partial blockage or
restrictions.
- Fuel injectors with partially blocked and restricted nozzles, or a
malfunctioning solenoid. Refer to
Fuel Injector Diagnosis and Fuel Injector Circuit Diagnosis for diagnosis.
- Fuel injector ON time inadequate. When this condition is present, there
may be fuel spray at the
fuel injectors and the indicated fuel pressure may be correct, yet there may
not be enough fuel to
start the engine. If the engine control module (ECM) receives incorrect
inputs from the various
information sensors, the fuel delivered by the fuel injectors may be
inadequate to start the engine.
Check all the engine data parameters with a scan tool and compare the values
indicated with the
expected values or the values from a known good vehicle.
- Loose unsecured engine electrical grounds. Inspect the engine for good
secure electrical grounds.
- Water or foreign material in the fuel, which can cause either a no start
or a engine will not stay
running condition. During freezing weather water can freeze inside the fuel
system. The engine
may start after 30 min in a heated repair shop. The malfunction may not
recur until parked
overnight in freezing temperatures. Extreme weather conditions can cause
contaminated fuel to
prevent the vehicle from starting.
- An ignition system that is susceptible to moisture. An engine that
starts and runs after being
brought into a warm, dry repair shop, may be susceptible to moisture. Spray
water on the ignition
system components and wiring while cranking the engine in order to check for
an engine starting
or will not stay running concern.
Reference Information
Schematic Reference
Engine Controls Wiring Schematics (LTG)
Connector End View Reference
Component Connector End View Index
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
- Starting System Description and Operation
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 26792 HEI Spark Tester
For equivalent regional tools, refer to Special Tools (Diagnostic Tools) and
Special Tools (Mechanical Tools).
Circuit/System Verification
NOTE:
This diagnostic assumes the following:
- The battery is completely charged.
- The engine cranking speed is acceptable.
- There is adequate fuel in the fuel tank.
1. Crank the engine for up to 15 s.
2. Verify that P0201 - P0204, P0261, P0262, P0264, P0265, P0267, P0268,
P0270, P0271, P1248,
P1249, P124A, P124B, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157,
P0335,
P0336, P0351 - P0354, P0601, P0602, P0603, P0604, P0606, P0607, P060E, P062F,
P0685,
P0689, P0690, P069E, P1516, P1682, P2610, or P2635 is not set.
- If any of the DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle.
- Go to next step: If none of the DTCs are set
3. Ignition ON.
4. Verify the security indicator on the instrument panel cluster illuminates
momentarily.
- If the indicator stays ON or is flashing
Refer to Diagnostic Trouble Code (DTC) List - Vehicle and Immobilizer
Description and Operation.
- Go to next step: If the indicator does not stay ON and is not
flashing
5. Verify the scan tool Engine Speed parameter is greater than 0 RPM while
cranking the engine.
Refer to DTC P0335 or P0336 for further diagnosis.
- Go to next step: If greater than 0 RPM
6. Ignition OFF.
7. Disconnect a T8 ignition coil from a cylinder and spark plug.
8. Connect a J 26792 HEI Spark Tester between the boot of the ignition coil and
ground.
NOTE: An erratic or weak spark is considered a no spark condition.
9. Verify that the spark tester sparks while cranking the engine.
- If the spark tester does not spark
Refer to Electronic Ignition System Diagnosis for further diagnosis.
- Go to next step: If the spark tester sparks
10. Ignition ON.
NOTE:
- If the engine is too hot, high fuel pressure readings may result
due to hot soak fuel boiling. Allow the engine coolant
temperature to cool to less than 60º C (150º F) before
attempting to verify fuel pressure.
- The Fuel Pump Enable may need to be commanded On a few
times in order to obtain the highest possible fuel pressure.
- Additional DTCs may set when using the fuel pump output
control.
11. Command the Fuel Pump Enable On several times with a scan tool.
12. Verify that the scan tool Fuel Pressure Sensor parameter is between 345 -
650 kPa (50 - 94 psi)
while the fuel pump is running.
- If not within the specified range
Refer to Fuel System Diagnosis.
- Go to next step: If within the specified range
13. Verify that the scan tool Fuel Pressure Sensor parameter, after the pump
has turned OFF, decreases
to less than 600 kPa (87 psi), and does not decrease greater than 34 kPa (5 psi)
in 1 minute.
- If not within the specified range
Refer to Fuel System Diagnosis.
- Go to next step: If within the specified range
14. Verify that the conditions listed below do not exist:
- Collapsed or restricted air intake duct to the throttle body
- Restricted air filter
- Gas or coolant fouled spark plugs
- A skewed manifold absolute pressure (MAP) sensor. Refer to DTC P0106
- A skewed engine coolant temperature (ECT) sensor. Refer to DTC P0117,
P0118, or P0119
- A restricted exhaust system. Refer to Restricted Exhaust.
- Contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis.
- An engine mechanical condition, for example, worn timing chain and gears
or low
compression. Refer to Symptoms - Engine Mechanical or Engine Compression
Test
- If a condition exists
Repair as necessary.
- Go to next step: If no conditions exist
15. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strate
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
SEE MORE:
Touch and the following may
display:
Forward Collision System
Front Pedestrian Detection
Rear Cross Traffic Alert
Adaptive Cruise Go Notifier
Lane Change Alert
Forward Collision System
This feature will turn on or off
Forward Collision Alert (FCA) and
Forward Automatic Braking (FAB).
The Off
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
D