Mechanics

IGNITION MODULE

1995 Ford Mustang

Electrical problem
1995 Ford Mustang V8 Two Wheel Drive Automatic 188, 00 miles

I am having difficulty finding the problem with my 1995 Mustang GT. Let me explain what is going on. I bought the car not knowing what was wrong with it. It was apparently having an electrical problem that the previous owner was trying to chase because the electrical harnesses were spliced all over. Then it also had the radiator and fan out as well. I have replaced the engine and ignition harnesses, ignition module, coil, plugs, and wires and a 20 amp EEC fuse that was blown, the radiator and the fan. Once I did all of this, the car fired right up. It sounded good and was holding a steady idle. I was warming the car up so that the thermostat could open and I could finish filling the radiator. Then all of a sudden, it just shut off, like the key had been turned. When I tried to restart it, there was no spark. I took the ignition module off and replaced it again and the car fired right back up. I have done this 3 times now and each time the car runs long enough to start to get warm, the ignition module goes out all over again. Does anyone have any suggestions as to what could be causing this? Thanks in advance for any and all advise.

Robert Bates
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Kaybee034
November 14, 2008.




Is the SES/MIL light on. If so we need to get the codes. So we can pinpoint the fault. You could try taking out and cleaning/replacing CKP sensor. They tend to breakdown when getting hot.

IGNITION SYSTEM
ELECTRONIC IGNITION (EI) (HIGH DATA RATE) SYSTEM
The EI (high data rate) system consists of a Crankshaft Position (CKP) sensor, Ignition Control Module (ICM) and one 6-tower coil pack.
The EI system operates by sending crankshaft position information from CKP sensor to ICM. The ICM generates a Profile Ignition Pick-Up (PIP) signal and sends it to the PCM.
The PCM responds with a Spark Output (SPOUT) signal containing advance or retard timing information back to the ICM. The ICM processes the CKP and SPOUT signals and decides which coils to fire. Also, the ICM generates an Ignition Diagnostic Monitor (IDM) signal to PCM, which is used to provide a tach output signal and indicate a failure mode if detected.
The CKP sensor is an electromagnetic device that senses movement of a 35 tooth wheel, located behind the crankshaft pulley. Each tooth is positioned in 10 degree increments with an empty slot (missing tooth) located 60 degrees BTDC. The detection of the missing tooth is what enables the PCM to identify crankshaft position and initiate correct firing order.
The ICM is a microprocessor with coil drivers. ICM strategy controls spark timing and coil firing. The ICM turns coils on and off at the correct time and in proper sequence, based on information from CKP sensor and a pulse width modulated signal (SPOUT) generated from PCM. The ICM receives CKP sensor and SPOUT signals and produces PIP and IDM output signals, which are sent to PCM.
The PCM receives ignition ground and PIP signals from the ICM, and then generates a SPOUT output signal based on engine speed, load, temperature and other sensor information. An IDM signal is received from ICM to determine if an ignition failure mode should be recorded.
The coil is turned on (coil charging) by ICM, and then turned off, firing 2 spark plugs at once. One plug is fired on the compression stroke; the other plug fires the mating cylinder, which is on the exhaust stroke. On the next cycle, firing strategy is reversed.

Dave H
Nov 15, 2008.
According to my Haynes manual, the 5.0's don't have a crankshaft sensor. Is this wrong or right?

Tiny
Kaybee034
Nov 15, 2008.
I am sorry you are right NO. CKP sensor. I was looking at 3.8L.

IGNITION SYSTEM
DISTRIBUTOR IGNITION (DI)
The DI system (formerly Thick Film Ignition-IV (TFI-IV) system) has 2 distinct configurations. In the first configuration, the Ignition Control Module (ICM) is mounted on the distributor. The ICM has 3 pins, which plug into the Hall Effect Camshaft Position (CMP) sensor located within the distributor. In the second configuration, ICM is not mounted on distributor but in another location within engine compartment.
The components of both configurations consist of ICM, distributor CMP sensor and " E" core ignition coil. The distributor used on the distributor-mounted ICM is a universal distributor with an opening for the ICM. The distributor used on remote-mounted ICM is a sealed distributor. On both distributors, the CMP is located within the distributor. There are no mechanisms within either distributor for centrifugal or vacuum advance.
The CMP sensor responds to a rotating metallic shutter on the distributor shaft and produces a Profile Ignition Pick-Up (PIP) signal. The PIP signal provides base timing information and is an indication of engine RPM and position. Since the shutter is mounted on the distributor shaft, 2 engine crankshaft revolutions are required to fire each spark plug once. This is because distributor rotates at half of crankshaft speed.
The internal circuitry of the ICM will have one of 2 arrangements, push-start or Computer-Controlled Dwell (CCD). The push-start system allows for increased dwell, or coil ON time, when starting engine. The ICM determines when to turn coil on based upon engine RPM information. The coil is then turned on or off, whenever a rising edge of a Spark Output (SPOUT) signal is encountered. The SPOUT signal is a digital signal generated by the Powertrain Control Module (PCM) to provide spark angle information to the ICM. The SPOUT signal controls only the firing of the coil. The falling edge of the SPOUT signal is ignored.
The CCD system is the same as push-start system, except the falling edge of the SPOUT signal is now generated to control coil ON time. The coil ON time, or dwell, is entirely controlled by the SPOUT signal. The ICM does not internally determine when to turn the coil on as it does on the push-start system. On the CCD system, the ICM responds directly to the SPOUT signal it receives.
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Dave H
Nov 16, 2008.
I greatly appreciate all of your help but I am still unsure as to what to try next. What would you suggest that I try? Would you suggest replacing the PIP? My car has the 2nd configuration of the DI system. The ICM is located on the fenderwell underneath the air cleaner system.

The reason we are having difficulty figuring this out is that when we install a brand new module, the car will start up and hold an idle like a brand new car. Then, within 15 minutes of letting it run, something is burning the NEW module out over and over again. We did not buy inferior auto parts either. I have spent over $1300 in parts just for the electrical system and still have the same problem.

Thanks again for your time and help. I hope the donation will help you for your time.

Tiny
Kaybee034
Nov 16, 2008.
I have not forgotten you? I'm looking into where we could be getting the backfeed from to the ICM

Dave H
Nov 16, 2008.
CIRCUIT TEST NA - DISTRIBUTOR IGNITION SYSTEM (DI) IGNITION DIAGNOSTIC MONITOR (IDM)
Diagnostic Aids
The IDM is an input signal to the PCM that verifies spark plug fire based on ignition coil primary discharge. IDM signal consists of a single pulse for each engine RPM. No IDM pulse indicates secondary ignition misfire.
Perform this test when directed by QUICK TEST. This test is only intended to diagnose EEC-IV portion of ignition system. For additional information on ignition system and component testing, see the I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) article. To prevent replacing good components, be aware the following non-EEC related areas may be cause of problem: Ignition Control Module (ICM).
Ignition coil.
Spark plugs and/or wires.
Distributor.
Secondary ignition short to ground.
This test is intended to diagnose: IDM circuit.
Faulty PCM.
Fig. 48: IDM Circuit Schematic
TEST PIN NO. 4 (IDM) WIRE COLOR IDENTIFICATION
ApplicationWire Color
MustangWhite/Pink

1) Continuous Memory Code 211

Code 211 indicates 2 successive erratic Profile Ignition Pick-Up (PIP) pulses occurred, resulting in a possible engine miss or stall. Check for the following possible causes of fault: Loose wires or connectors.
Arcing secondary ignition components.
On-board transmitter equipment (2-way radio).
If any of the above possible causes are present, repair as necessary. Clear code, and repeat QUICK TEST. If problem is not found, go to next step. If vehicle does not start, go to IGNITION SYSTEMS in the I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) article.
2) Continuous Memory Code 212: Check IDM Circuit Continuity

Continuous Memory Code 212 indicates loss of IDM input to PCM. Possible causes for this fault are: Open or shorted circuit in wiring harness.
Faulty ICM.
Faulty PCM.
If vehicle is a no-start, see IGNITION SYSTEMS in the I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) article. If vehicle starts, go to next step.
3) Check IDM Circuit Continuity

Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect ICM. Measure resistance between test pin No. 4 at breakout box and IDM circuit terminal at ICM wiring harness connector. If resistance is less than 5 ohms, go to step 5). If resistance is 5 ohms or more, repair open circuit, and repeat QUICK TEST.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 5). No test procedures have been omitted.

5) Check IDM Circuit For Short To Power (Except VREF)

Turn ignition off. Leave ICM and PCM disconnected. Measure voltage between breakout box test pin No. 4 and negative battery terminal. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If any reading is more than 10.5 volts, repair short circuit. Clear codes, and repeat QUICK TEST. If both readings are 10.5 volts or less, go to next step.
6) Check IDM Circuit For Short To PIP & VREF

Turn ignition off. Leave PCM and ICM disconnected. Remove scan tool (if applicable). For shorts to PIP, measure resistance between test pins No. 4 and No. 56 at breakout box. For shorts to VREF, measure resistance between test pins No. 4 and No. 26 at breakout box. If either resistance is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat QUICK TEST. If each resistance is more than 10,000 ohms, go to next step.
7) Check IDM Circuit For Short To Ground

Turn ignition off. Leave ICM and PCM disconnected. Measure resistance between test pin No. 4 and test pins No. 20, 40, 46 and 60 at breakout box. If each resistance is more than 10,000 ohms, go to next step. If any resistance is 10,000 ohms or less, repair short to ground in IDM circuit. Remove breakout box, reconnect all components, and repeat QUICK TEST.
8) Check ICM

Turn ignition off. Connect PCM to breakout box. Reconnect ICM to wiring harness connector. Connect DVOM between test pins No. 4 and 16 at breakout box. Start engine. Observe DVOM for voltage surge while lightly tapping on ICM and Camshaft Position (CMP) sensor (if equipped) to simulate road shock. Wiggle all ICM and CMP sensor wiring and harness connectors. If fault (voltage surge) is not indicated, go to next step. If fault (voltage surge) is indicated, disconnect and inspect wiring harness connectors and terminals for damage. Repair as necessary. If connectors and terminals are okay, check ignition system. See the I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) article.
9) Check PCM & Harness Connectors

Ensure engine is still running and DVOM is still connected between test pins No. 4 and 16 at breakout box. While observing DVOM, wiggle and bend wiring harness, a small section at a time, from ICM and CMP sensor (if equipped) to cowl. Also, check harness from cowl to PCM. If fault is indicated, isolate fault and repair as necessary. Remove breakout box, reconnect all components, and repeat QUICK TEST. If no fault is found, go to next step.
10) Check PCM & Harness Connectors

Turn ignition off. Disconnect PCM 60-pin connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. If connector is damaged, repair as necessary. Remove breakout box, reconnect all components, and repeat QUICK TEST. If connector is okay, go to next step.
11) Check PCM For Short To Power

Turn ignition off. Connect PCM to breakout box. Disconnect the following sensors as applicable.
On vehicles with remote mounted ICM and CMP, disconnect ICM and CMP wiring harness connector.
On all other models, disconnect ICM wiring harness connector.
On all models, measure voltage between test pin No. 4 at breakout box and chassis ground. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If any reading is more than 10.5 volts, replace PCM. Remove breakout box, reconnect all components, and repeat QUICK TEST. If both readings are 10.5 volts or less, go to next step.
12) Check PCM For Short To Ground

Turn ignition off. Leave PCM connected to breakout box. Disconnect ICM and CMP. Measure resistance between test pin No. 4 and test pins No. 40, 46 and 60 at breakout box. If all readings are more than 10,000 ohms, check ignition system. See the I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) article. If any reading is 10,000 ohms or less, replace PCM. Remove breakout box, reconnect all components, and repeat QUICK TEST.

Dave H
Nov 16, 2008.
I replaced the pick-up in the distributor and so far so good. It hasn't burned up another module yet. If all goes well, I will confirm that a bad pick-up was burning out the module. Thanks again for your help.

Tiny
Kaybee034
Nov 18, 2008.
Glad to be of help. Will be keepin my fingers crossed.

Happy motoring

Dave H

Dave H
Nov 19, 2008.

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