ignition problem PLEASE HELP!

[perna00]

My 96' 2.4 dohc engine wont start. i tested everything and found that the ignition module has a +12 volt output but is not sending a negative pulse to either of the coil packs to engage a spark. the only problem is that i already replaced the ignition module, both coil packs, coil pack housing, wires, plugs, cranksensor, and pcm/ecu. any help would be very appriciative. thank you.

[fluffybunny]

i assume youve had the recall done on your car......ignition thermal events? if so have you had your neutral safety switch checked? we need a little more nfo also, is it turning over or just turning on... like no engine rotation, but lights and bells? ive got a 96 2.4 also and ive just about repaier or messed with everything on my car. so ive got a little bit of know how.....not the best but ive got a few hours under the hood...... keep replying

[perna00]

the engine will turn over, gets fuel, gets everything except a spark. the problem is that the ignition module is not sending a signal to the coils to tell them when to spark. i think it's in the wiring but i'm not sure. i replaced the crank sensor and took reading of the crank and cam sensors. they both fluctuate between 2-10 volts when i'm cranking the engine. the only thing i found odd is that if i have the connector off the cam positioning sensor the reading on the wires by themself with the car on is +12 volts on one wire and both the other 2 have a -12 volt (ground) reading. but when ever i crank the engine the reference wire still fluctuates like normal. any more ideas?

[fluffybunny]

The camshaft position (CMP) sensor correlates the crankshaft to camshaft position so that the Powertrain Control Module (PCM) can determine which cylinder is ready to be fueled by the injector. The CMP sensor also determines which cylinder is misfiring when a misfire is present. If the PCM receives an intermittent signal from the CMP, then the CMP Resync Counter will increment. When the PCM cannot use the information from the CMP sensor, a DTC is set and the PCM will fuel the engine by using the alternating synchronous double fire (ASDF) method.

thats out of the gm web page, id say removing the plug causes the higher voltage as it kicks into asdf. you said you replaced the crank sensor, i think there is a srank sensor relearn procedure, you know about that? other than that id say youre right about tracking a dead wire somewhere. where is our resident tech? i think youre out of my league. im getting that the crank sensor is responsible for sending spark timing and the cam sensor is for injector pulse. do you have any codes set that may prevent you from cranking? ill try to find more out for ya,

[perna00]

nope, don't have any codes in memory except for a p0300 from a random multiple cylinder misfire from before the ignition problem. i see that the only wires going to the ignition module come from the crank sensor, the pcm, and it's own power and ground. any way you could possible find out what reading they should have? it might be hard to find though. thanks for the help so far.
think that the crank sensor relearn program would cause my problem? i never heard of it.

[fluffybunny]

CKP System Variation Learn Procedure

Important
A Crankshaft Position System Variation Learning Procedure must be performed any time a change is made to the crankshaft sensor to crankshaft relationship. Changing the crank sensor to crankshaft relationship will not allow the PCM to detect misfire at all speeds and loads accurately. Resulting in a possible false misfire DTC being set.


Removing a part for inspection and then reinstalling the same part is considered a disturbance. A false DTC P0300 could be set if this procedure is not performed.

The learn procedure is required after the following service procedures have been performed, regardless of whether or not DTC P1336 is set:

PCM replacement.
Engine replacement.
Crankshaft replacement.
Crankshaft position sensor replacement.
Any engine repairs which disturbs the crankshaft/harmonic balancer to the crankshaft position sensor relationship.

Caution
Before performing the Crankshaft Position System Variation Learning Procedure always set the vehicle parking brake and block the drive wheels in order to prevent personal injury. Release the throttle immediately when the engine starts to decelerate in order to eliminate over revving the engine. Once the learn procedure is completed, the control module will return engine control to the operator and the engine will respond to the throttle position.



Important
The battery must be fully charged and in good condition. The scan tool connection at the DLC is clean and tight before starting the Crankshaft Position System Variation Learning Procedure.


Close the hood.
Block the drive wheels and set the vehicle parking brake.
Put the vehicle in Park or Neutral.
Turn all the accessories OFF.
Install a scan tool.
Start and run the engine until it is at normal operating temperature 85°C (185°F).
With the engine still running, enable the Crankshaft Position System Variation Learning Procedure with the scan tool.
Press and hold the brake pedal firmly and raise the engine speed to the specified value, RELEASING the throttle as soon as the engine cuts out.
Verify with the scan tool that the crankshaft variation has been learned.
Perform this procedure up to 10 times. If the PCM will not learn the variation, a DTC P1336 should be set. Refer to the DTC P1336 Crankshaft Position (CKP) System Variation Not Learned for diagnosis.

© Copyright General Motors Corporation. All Rights Reserved.

[fluffybunny]

Engine Cranks but Does Not Run




Circuit Description
This engine is equipped with a distributorless ignition system called the Electronic Ignition (EI) system. The primary circuit of the EI system consists of the following items:

Two separate ignition coils
Electronic Ignition Control Module (ICM)
Crankshaft Position (CKP) sensor
Related connecting wires and the ignition control portion of the PCM
Each secondary circuit consists of the following items:

Secondary winding of the coil
Two connecting metal strips that are molded into the coil housing
Spark plug boot/connector assemblies
Spark plugs
Diagnostic Aids
A small amount of resistance in the battery positive voltage circuit to the PCM may cause a no start with a functioning MIL. Check the battery positive voltage circuit for excessive resistance or corrosion.
Check the Throttle Position (TP) sensor for binding or sticking or for being intermittently shorted or open.
If the THEFT SYSTEM telltale is flashing on the Instrument Panel Cluster (IPC), the theft deterrent system has been activated, refer to DTC P1629 Theft Deterrent Fuel Enable Signal Not Received for further diagnosis.
Check for water or foreign material in the fuel system.
Check for a basic engine problem (low compression).
Verify that only resistor spark plugs are used.
A scan tool can be used to energize the fuel pump ON to check the fuel pump operation and for ignition voltage at the fuel injector harness.
Test Description
Numbers below refer to the step numbers on the Diagnostic Table.

The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored in the scan tool for later reference.

Diagnosis of the DTCs that may be set could lead to the cause of the Cranks But Will Not Run condition.

The PCM grounds will only cause a problem if all the grounds are not making a good connection. If a PCM ground problem is suspected, the most probable place to check is where all the grounds meet at the engine block.

Locate and repair any shorts that may have caused the fuse to open before replacing the fuse.

A TP sensor that reads too high may cause an incorrect fueling condition (Clear flood enabled).

An engine that has not been started or recently started should display ECT and IAT temperatures that are relatively close to each other. During the warmer weather, the IAT readings maybe slightly higher than the ECT readings. If a malfunctioning coolant sensor is suspected, the spark plugs may have fouled out and need to be replaced to start the engine.

If the scan tool loses serial data only while cranking the engine, then the ignition switch is not sending voltage to the PCM while in the crank position.

This step looks for a normal barometer reading and a change in MAP sensor values while cranking the engine. This step verifies the MAP sensor can detect the change in the manifold pressure that occurs while cranking the engine. Compare any questionable barometer readings with readings from another vehicle. If a malfunctioning MAP sensor is suspected, the spark plugs mat have fouled out and need to be replaced.

While cranking the engine, the CKP Activity (7X reference should increment to 255, then rollover to 0.

Check for possible voltage loss to the PCM including the ignition switch itself.

The ignition positive voltage should be available at the ignition feed terminal (L) of the ICM 11 pin harness electrical connector, and the ground terminal (K) should be a good ground.

The CKP sensor core is a magnet and should be magnetized.

The CKP sensor should output a AC voltage near 1100-1300 mV as the crankshaft turns. It is possible to trigger the ICM with a voltage as low as 200 mV. If no voltage is produced, a poor CKP sensor electrical connection or a malfunctioning CKP sensor is indicated.

The test light connected to B+ simulates a reference signal to the PCM. A fuel injector test light can be installed and will blink for every other touch of the test light if the CKP Activity (7X reference) circuit, the PCM and the fuel injector driver circuits are all functioning properly.

If the test light illuminates while probing the CKP Activity (7X reference) circuit, then the CKP Activity (7X reference) circuit is shorted to ground. If the test light remains OFF and the CKP Activity Counter does not increment, then the CKP Activity (7X reference) circuit is open. If the CKP Activity Counter increment several counts, when the reference low (terminal H) is probed, then the CKP Activity (7X reference) is shorted to voltage.

Replacement PCMs must be reprogrammed and the crankshaft position system variation learn procedure must be performed. Refer to the latest Techline information for PCM programming and to CKP System Variation Learn Procedure .

Battery voltage should be available at the fuel injector ignition feed circuit whenever the fuel pump power feed circuit is switched ON and when the PCM is receiving ignition pulses, during engine cranking or when running. The ignition switch must be turned OFF for at least 10 seconds to assure that the PCM powers down and will then switch the fuel pump back ON for 2-3 seconds when the ignition switch is turned back ON.

By installing the spark plug jumper leads and testing for spark on all 4 plug wire leads (one at a time), each ignition coils ability to produced at least 25,000 volts is verified.

The fuel pump is turned ON by the PCM for 2-3 seconds after ignition switch is first turned ON. This step checks to see if the fuel pump and fuel pump relay are operating correctly and if the fuel pressure is within the proper range. Refer to the Fuel System Diagnosis .

This step verifies that the PCM is sending a signal to the Ignition Control Module (ICM) to fire the ignition coils. If the test light blinks, then the signal is OK to this point and the no spark condition lies in the ignition coil electrical harness or the ignition coil that did not produce spark.

The ignition coil electrical harness can easily be checked by performing the previous step with the ignition coil electrical harness connected to the ICM. Check for a voltage and ground signal to the ignition coils at the coil electrical connector.

Engine Cranks But Will Not Run Step
Action
Value(s)
Yes
No

1
Was the Powertrain On-Board Diagnostic (OBD) System Check performed?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2
Turn ON the ignition switch leaving the engine OFF.
Install a scan tool.
Are DTCs P0601, P0602, P1629 set?
--
Go to applicable DTC table
Go to Step 3

3
Inspect the PCM ground connections at the engine block.

Is the ground connection OK?
--
Go to Step 4
Go to Step 5

4
Inspect the following fuses:

Fuel pump and injector feed
Ignition positive voltage feed
Are the fuses OK?
--
Go to Step 6
Go to Step 7

5
Repair the PCM ground connection. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?
--
Go to Step 37
--

6
Check the fuel level.
Add fuel if necessary.
Was it necessary to add fuel?
--
Go to Step 37
Go to Step 8

7
Check for a short to ground in the following circuit(s):
Fuel pump/Fuel injector feed
Ignition Positive Voltage to the ICM
Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Replace the open fuse.
Is the action complete?
--
Go to Step 37
--

8
Verify that the throttle is closed.
Check the TP sensor reading with the scan tool.
Does the TP sensor read less then the specified value?
1.0 V
Go to Step 9
Go to DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage

9
Is the Engine Coolant Temperature (ECT) relatively close to the Intake Air Temperature (IAT)?
--
Go to Step 10
Go to DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage

or DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage

10
Crank the engine while watching the MAP sensor readings on the scan tool.

Was serial data lost while cranking the engine?
--
Go to Step 13
Go to Step 11

11
Check to see if the Manifold Absolute Pressure (MAP) sensor reading is over the specified value with the scan tool.
Crank the engine.
Does the MAP sensor read over the specified value and then change while cranking the engine?
4.0 V
Go to Step 12
Go to Manifold Absolute Pressure (MAP) Sensor Output Diagnosis

12
Check to see if the CKP Activity Counter increments while cranking the engine with the scan tool.

Does the CKP Activity Counter increment while cranking?
--
Go to Step 28
Go to Step 14

13
Repair the voltage loss to the PCM from the ignition switch. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?
--
Go to Step 37
--

14
Turn OFF the ignition switch.
Disconnect the electronic Ignition Control Module (ICM) 11 pin harness electrical connector.
Turn ON the ignition switch leaving the engine OFF.
Connect the DMM between the following circuit terminals:
ICM ground terminal
Ignition positive voltage terminal
Does the DMM read the specified voltage?
B+
Go to Step 15
Go to Step 16

15
Connect the DMM between the following terminals:
CKP sensor signal terminal (cavity F)
CKP sensor ground terminal (cavity J)
Measure the combined resistance of the CKP sensor and ICM electrical harness with the DMM.
Is the resistance reading within the specified value?
500-900ohms
Go to Step 19
Go to Step 18

16
Repair the poor electrical terminal connection or open in the following ICM circuit(s): Refer to Wiring Repairs in Wiring Systems.

Ignition positive voltage circuit
Ground circuit
Is the action complete?
--
Go to Step 37
--

17
Check the CKP signal circuit for a short to ground.
Repair as necessary.
Was a repair necessary?
--
Go to Step 37
Go to Step 23

18
Turn OFF the ignition switch.
Remove the CKP sensor from the engine. Refer to Crankshaft Position (CKP) Sensor Replacement
Connect the DMM across the CKP sensor terminals. (CKP sensor side)
Measure the CKP sensor resistance with the DMM.
Check and verify the following condition(s):
CKP sensor is magnetic
CKP terminals for damage
CKP sensor is not damaged
Is the CKP sensor magnetic with undamaged terminals and the resistance within the specified value?
500-900ohms
Go to Step 22
Go to Step 23

19
Connect the DMM between following ICM harness electrical connector terminals:
CKP sensor Signal circuit (cavity F)
CKP sensor ground circuit (cavity J)
Note the voltage (AC scale) on the DMM.
Crank the engine.
Is the voltage reading greater than the specified value?
200 mV
Go to Step 20
Go to Step 17

20
Check for a short to voltage in the CKP sensor signal circuit.
Repair the short as necessary. Refer to Wiring Repairs in Wiring Systems.
Is the action complete?
--
Go to Step 37
Go to Step 21

21
Connect a test light to the ICM 7x Reference Signal circuit terminal (Cavity G ) electrical harness connector side.
Use the clip end of the test light to touch the battery negative terminal and then touch the battery positive terminal. Keep alternating between the terminals while watching the scan tool.
Does the CKP Activity Counter increment one count as the test light touches the 7x Reference signal terminal (cavity G)?
--
Go to Step 24
Go to Step 25

22
Check for the following conditions in the CKP sensor electrical harness signal and ground circuit(s):
Poor electrical terminal connection at the CKP sensor
Open in the circuit
Repair the circuits as necessary. Refer to Wiring Repairs in Wiring Systems.
Is the action complete?
--
Go to Step 37
--

23
Replace the CKP sensor. Refer to the Crankshaft Position (CKP) Sensor Replacement .

Is the action complete?
--
Go to Step 37
--

24
Visually inspect the ICM harness electrical connector for the following condition(s):
Damaged terminals
Electrical terminals are clean and tight
Backed out terminals
Repair the connector as necessary. Refer to Wiring Repairs in Wiring Systems.
Was a repair necessary?
--
Go to Step 37
Go to Step 26

25
Check the CKP activity (7X reference) circuit for the following condition(s):
Open circuit
Short to ground
Short to voltage
Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.
Was a repair necessary?
--
Go to Step 37
Go to Step 27

26
Replace the ICM. Refer to the Ignition Control Module Replacement .

Is the action complete?
--
Go to Step 37
--

27
Turn OFF the ignition switch.
Check for a poor electrical terminal connections at the PCM, if OK replace the PCM. Refer to the PCM Replacement/Programming .
Is the action complete?
--
Go to Step 37
--

28
Disconnect all of the fuel injectors electrical connectors.
Install J 34730-2A Fuel Injector Test Light on fuel injector #1 electrical connector.
Crank the engine and note the light.
Does the test light blink?
--
Go to Step 29
Go to Fuel Pump Electrical Circuit Diagnosis

29
Remove the ignition coil and the electronic ignition control module assembly. Refer to Ignition Control Module Replacement for the removal procedure.
Install the J 36012-A spark plug jumper wires.
Install the J 26792 spark tester on the #1 spark plug jumper wire.
Remove the spark plug boot assembly from the #4 companion cylinder of the ignition coil housing
Install a jumper wire from the #4 spark plug connector at the ignition coil housing to ground.
Crank the engine with the remaining spark plug wires still connected.
Check for spark with the spark tester on all 4 spark plug wires (one at a time).
Does spark jump the spark tester on all 4 spark plug wires?
--
Go to Step 30
Go to Step 32

30
Install a fuel pressure gauge.

Important
The ignition switch may have to be cycled more than one time to achieve the highest fuel pressure.


Note the fuel pressure after the ignition switch is turned ON for 2 seconds.
Is the fuel pressure between the specified value?
284-325 kPa (41-47 psi)
Go to Step 31
Go to Fuel System Diagnosis

31
Check for fouled spark plugs. Refer to the Spark Plug Visual Diagnosis in Engine Electrical.
Replace the spark plugs if necessary. Refer to the Spark Plug Replacement in Engine Electrical.
Was any spark plug replacement necessary?
--
Go to Step 37
Go to Diagnostic Aids

32
Turn the ignition switch OFF.
Disconnect the PCM electrical connector (C1).
Turn ON the ignition switch leaving the engine OFF.

Notice
Do not leave the test lamp connected to the PCM IC circuit connector for longer than 5 seconds at a time. Failure to do so may damage the ignition coil and/or the Ignition Control Module.


Connect a test light to B+.
Momentarily probe the IC Input circuit for the coil that did not spark with the test light.
Remove the test light from the IC Input circuit and a spark should jump from the spark tester.
Does a spark jump on the spark tester?
--
Go to Step 27
Go to Step 33

33
Turn the ignition switch OFF.
Disconnect the spark plug jumper wires.
Remove the ignition coil housing from the cover. Refer to Ignition Coil(s) Replacement for the removal procedure.
Disconnect the ignition coil harness electrical connector from the ICM.
Connect another test light to B+.
Probe the ICM control terminal for the ignition coils which did not spark with the test light.

Notice
Do not leave the test lamp connected to the PCM IC circuit connector for longer than 5 seconds at a time. Failure to do so may damage the ignition coil and/or the Ignition Control Module.


Again, momentarily touch the affected IC circuit at the PCM electrical connector (C1-25 or C1-26) with the test light while watching the other test light.
Does the other test light blink?
--
Go to Step 34
Go to Step 36

34
Check the coil control circuit between the ignition coils and the ICM for the following condition(s):
Poor ignition coil harness electrical terminal connection(s)
Open in the coil control circuit(s)
Short to ground in the coil control circuit(s)
Short to battery voltage in the coil control circuit(s)
Open in the ignition feed circuits to the ignition coil(s)
Repair the conditions found as necessary. Refer to Wiring Repairs in Wiring Systems.
Was a repair necessary?
--
Go to Step 37
Go to step 35

35
Replace the ignition coil that did not spark. Refer to the Ignition Coil(s) Replacement .

Is the action complete?
--
Go to Step 37
--

36
Check the IC input circuit between the ICM and the PCM for the following condition(s):
Poor electrical terminal connection
Open circuit
Short to ground
Short to voltage
Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.
Was a repair necessary?
--
Go to Step 37
Go to Step 24

37
Reconnect all previously disconnected components (if not already connected).
Using the scan tool, clear any DTCs.
Attempt to start the engine.
Does the engine start and continue to run?
--
Go to Step 38
Go to Step 2

38
Allow the engine to idle until normal operating temperature is reached.
Check if any DTCs are set.
Are any DTCs displayed that have not been diagnosed?
--
Go to Applicable DTC table
System OK


© Copyright General Motors Corporation. All Rights Reserved.

[perna00]

that info will help me out alot. now i got to get the scan tool again. hopefully i'll be able to get it soon and i'll let you know what i find out. also, any chance a bad camshaft positioning sensor could cause it not to start?

[fluffybunny]

well i guess if it wasnt telling the injectors to pulse, id assume it would keep it from starting.

[perna00]

well it's the spark, not the injectors so that takes that out. only thing left to do is try scanning in the cranksensor because i never programmed it after i changed it

[perna00]

can anyone tell me if the reading should vary between 750-850 for the ohms of the crankpositioning sensor?

[fluffybunny]

Is the CKP sensor magnetic with undamaged terminals and the resistance within the specified value?
500-900ohms
thats from above. i think your reading is ok. still no start?
The CKP sensor should output a AC voltage near 1100-1300 mV as the crankshaft turns. It is possible to trigger the ICM with a voltage as low as 200 mV. If no voltage is produced, a poor CKP sensor electrical connection or a malfunctioning CKP sensor is indicated. above also......
i think its just a matter of electrical troubleshooting to find the culprit. the long diagnostic procedure above is just about everything you should need. and i dont want to sould like im being a smart ass but your pcm was reprogrammed right? iv eheard of bad pulls on pcms also. i feel like this is my car and i cant figure the problem out. id like to help you see this through though.

[perna00]

unfortuately i can't get a scan tool until at least this coming weekend. i'm trying to figure it out without it until then. i actually had the car start once and it ran decent for a few minutes then started cutting in and out very quickly until it eventually stalled out and wouldn't start. i reved the engine a bit and it still did the exact same thing while it was running. it was like the ignition would completely shut off for a sec then come back on. the pcm was programmed by the company i bought it from and all data was given.

[perna00]

fluffybunny, your $%$#ing awesome. thanks for the info. i found from the steps you posted that one of the metal plates that keeps pressure between the connector and the ignition module was broken. i bent what was left together so the connection would be solid and it started right up. i added a star to your reputation for all the help. thanks again-jake