Need Help

( SORRY ABOUT THE CAPS - MY KEY BOARD IS GIVING ME FITS)
Document ID# 316532
1999 Chevrolet/Geo Corvette
--------------------------------------------------------------------------------
Engine Cranks but Does Not Run
Refer to Cell 20: CKP, CMP, KS and Traction Control System for complete circuit details.
Description
The Engine Cranks but Does Not Run diagnostic table assumes that battery condition and engine cranking speed are OK. If the battery condition and the cranking speed are not OK, refer to Starting System Check or Charging System Check in Engine Electrical for diagnosis. Make sure that there is adequate fuel in the tank(s).
Diagnostic Aids
Important
Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.
Inspect the duct work between the Mass Air Flow (MAF) sensor and the throttle body for air leaks.
A malfunctioning MAF sensor may cause a no start or a stall after start. If you suspect this, disconnect the MAF sensor. The PCM will default to the speed density (MAP, IAT, RPM) in order to calculate the load and the air flow. If this corrects the condition and the connections are OK, replace the MAF sensor.
For an intermittent condition, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
This step verifies the IGN relay for proper operation. The IGN relay supplies voltage to the injectors and the ignition coils. When the IGN relay is not operating properly, a no start condition occurs. If the test lamp does not illuminate, this indicates the IGN relay is not suppling a voltage to the fuses.
This step is testing for a DTC that sets while the engine is cranking.
This step is testing for a grounded ignition feed circuit for the crankshaft position sensor and the camshaft position sensor. When the ignition feed circuit is shorted, a no start occurs and no DTCs are set. The ignition feed circuits are connected internally within the PCM. The PCM cannot detect that the engine is cranking with a grounded ignition feed circuit. If no engine speed is displayed on the scan tool, inspect the ignition feed circuit for a short to ground.
The scan tool may reset if the battery is at a low state of charge. The battery may need to be charged to perform this step.
This step is testing for B+ supply to the crankshaft position sensor.
The ignition feed circuits for the Camshaft and Crankshaft Position sensors is internally connected within the PCM. A short to ground on either circuit will cause a no start condition.
The fuel cap may need to be removed in order to hear if the fuel pump is operating.
Step
Action
Value(s)
Yes
No
1
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check
2
Turn ON the ignition leaving the engine OFF.
Probe both sides of the fuses (located in the Underhood Electrical Center) listed below using the test lamp J 34142-B connected to ground.
INJR1
INJR2
THROT CONT
ENG IGN 1
A/C
Does the test lamp illuminate on both sides of all the fuses?
--
Go to Step 3
Go to Ignition Relay Diagnosis for further diagnosis
3
Monitor the Diagnostic Trouble Code (DTC) option using the scan tool.
Does the scan tool display any Throttle Actuator Control (TAC) system DTCs?
--
Go to the applicable DTC table
Go to Step 4
4
Important
Monitor the BCM for DTCs related to Vehicle Theft Deterrent (VTD) system. This indicates a concern with the Column Lock or VTD fuel enable system. If a BCM DTC is stored, refer to Diagnostic System Check - Body Control System in Body Control Systems.
Select the Diagnostic Trouble Code (DTC) option, then the DTC Information option using the scan tool.
Is P0230, P0335, P0336, P0601, P0602, P0604, or P0606 displayed?
--
Go to the applicable DTC table
Go to Step 5
5
Monitor the Diagnostic Trouble Code (DTC) option using the scan tool.
Crank the engine for 15 seconds.
Did a DTC set while cranking the engine?
--
Go to the applicable DTC table
Go to Step 6
6
Monitor the engine speed while cranking the engine.
Is engine RPM indicated on the scan tool?
--
Go to Step 10
Go to Step 7
7
Turn OFF the engine.
Disconnect the Crankshaft Position (CKP) sensor electrical connector. Refer to Crankshaft Position (CKP) Sensor Replacement .
Turn ON the ignition leaving the engine OFF.
Measure the voltage at the ignition feed circuit at the CKP electrical connector using the DMM J 39200 .
Does the DMM display near the specified value?
B+
Go to Step 14
Go to Step 8
8
Disconnect the Camshaft Position (CMP) sensor electrical connector. Refer to Camshaft Position (CMP) Sensor Replacement .
Measure the voltage at the ignition feed circuit at the CMP electrical connector using the DMM J 39200 .
Does the DMM display near the specified value?
B+
Go to Step 15
Go to Step 9
9
Test the Camshaft and Crankshaft Position sensor ignition feed circuits for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 17
Go to Step 16
10
Monitor the engine coolant temperature using the scan tool.
Is the engine coolant temperature on the scan tool close to the actual engine temperature?
--
Go to Step 11
Go to DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage
11
Enable the fuel pump using the scan tool.
Does the fuel pump operate?
--
Go to Step 12
Go to Fuel Pump Electrical Circuit Diagnosis
12
Turn OFF the ignition.
Install a fuel pressure gauge. Refer to Fuel System Diagnosis .
Turn ON the ignition leaving the engine OFF.
Observe the fuel pressure while the fuel pump is operating.
Is the fuel pressure within the specified range?
380-420 kPa (55-61 psi)
Go to Step 13
Go to Fuel System Diagnosis
13
Perform the following additional inspections:
Inspect the duct work between the Mass Air Flow (MAF) sensor and the throttle body for air leaks.
A malfunctioning MAF sensor may cause a no start or a stall after a start. If you suspect this, disconnect the MAF sensor. The PCM will default to the speed density (MAP, IAT, RPM) in order to calculate the engine load and the intake air flow. If disconnecting the MAF sensor corrects the condition and the connections are OK, replace the MAF sensor.
Inspect the spark plugs for being gas fouled. If the spark plugs are gas fouled, determine what caused the rich condition.
Inspect for an engine mechanical failure that causes an engine not to start (i.e. timing chain, low compression).
Compare MAP/BARO parameters to another vehicle. The parameter values should be close to each other.
Did you find and correct the condition?
--
Go to Step 17
Go to Symptoms for diagnosis
14
Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement .
Is the action complete?
--
Go to Step 17
--
15
Replace the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement .
Is the action complete?
--
Go to Step 17
--
16
Important
Program the replacement PCM. Refer to PCM/TAC Module Replacement .
Replace the PCM.
Is the action complete?
--
Go to Step 17
--
17
Select the Diagnostic Trouble Codes (DTC) option and the Clear DTC Information option using the scan tool.
Attempt to start the engine.
Does the engine start and continue to run?
--
Go to Step 18
Go to Step 2
18
Idle the engine at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option.
Are any DTCs displayed?
--
Go to the applicable DTC table
Go to Step 19
19
Select the Capture Info option and the Review Info option using the scan tool.
Are any DTCs displayed that you have not diagnosed?
--
Go to the applicable DTC table
System OK
--------------------------------------------------------------------------------





http://forums.corvetteforum.com/showthread.php?t=896875
If you have any questions on your grounds,, PM me and I will give you some ONE ON ONE assistance.
Another thing to check is your SPARK. Use a screwdriver and insert it into the removed spark plug boot and hold it with in 1/8" of a good ground. You should see a good solid blue spark.
Bill
Bill C






