Again with no codes
Thread Starter
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Lead Driver
Joined: Oct 2004
Posts: 8,062
Likes: 35
From: Central Oregon
Again with no codes
My wifes 90 Aero with the 4.0 engine is still fighting me, CEL comes on randomly, but runs fine. Also at times it is hard to start, like no spark. When it does the no spark thing, you can smell gas. And still no codes. I did change the battery cables this week end, as I did read that they can cause a no code CEL. Wife call from work to tell me that it is NOT fixed. Will the coil stop working randomly? Any ideas would be great, thanks
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
the 4L uses EDIS
http://rockledge.home.comcast.net/~rockledge/RangerPictureGallery/DIS_EDIS.htm
the 4L coil pack is expensive, $150 at Ford parts counter.
i would try one from your local auto junke parts emporium first.
look for corrosion on input control cable contacts on your pack and the plug. common problem with the 4L because of mounting location, gets sprayed by any hose leak, antifreeze is an alkaline corrosive
check the CPS crankshaft position sensor down at the crank damper on front. the contacts get corroded in these also. the unit is susceptible to damage by broken belts or road debris. i've seen them torn off and MIA. many mudders carry a spare under the seat.
also check the ICM ignition control module on pass. fender wall, contacts and plug, they get sprayed when a hose breaks at heater core. never seen a ICM fail internally on a 4L but possible.
i would only go Motorcraft, Standard or ACDelco for new.
RockAuto has the best price
Ignition (4.0L)
The Electronic Ignition System consists of an Ignition Coil, Ignition Control Module (ICM), and Crankshaft Position (CKP) Sensor. The Ignition Coil pack contains three separate coils, each driven by a separate coil-driven output from the ICM. Each coil controls two spark plugs.
With the Ignition Switch in START, battery voltage is applied to the Ignition Coil through the 16 (R/LG) wire and Fuse Link G. When the Ignition Switch is released to the RUN position, voltage is applied through the 16 (R/LG) wire.
When the engine is running:
l The CKP sensor senses the crankshaft position.
l The Sensor sends a signal to the ICM and the PCM.
l The PCM then sends a timing signal back to the ICM.
l The ICM switches current on and off to the three Ignition Coil primary circuits as determined by the PCM signal. The sequence is determined by the ICM.
l Each interruption of a primary current makes the secondary current produce an open circuit high voltage pulse which is transmitted directly to the spark plugs.
l Similar to the Distributor Ignition System, the Electronic Ignition System provides a base timing signal if the timing signal from the PCM is missing.
REFERENCE :For diagnostic information, refer to «Section 2A » of the Powertrain Control/Emissions Diagnosis Manual.
ignition system problems do not always set a code
The Engine Running Wiggle Test may be activated any time the engine is running.
1. Hook up a STAR Tester, VOM or Scan Tool as shown.
2. Key off.
3. Start the engine.
4. For STAR Tester or VOM, activate Self-Test, deactivate and reactivate Self-Test. DO NOT shut the engine off. You are now in the Engine Running Continuous Monitor DTM. For Scan Tool, enter DTM, then enter wiggle DTM.
5. Tap, move, and wiggle the suspect sensor and/or harness or drive the vehicle. When a fault is detected, a Continuous Memory DTC will be stored in memory. This will be indicated as follows depending on the type of equipment being used:
l Malfunction Indicator Lamp (MIL): Lights
l VOM: Needle Sweep
http://rockledge.home.comcast.net/~rockledge/RangerPictureGallery/DIS_EDIS.htm
the 4L coil pack is expensive, $150 at Ford parts counter.
i would try one from your local auto junke parts emporium first.
look for corrosion on input control cable contacts on your pack and the plug. common problem with the 4L because of mounting location, gets sprayed by any hose leak, antifreeze is an alkaline corrosive
check the CPS crankshaft position sensor down at the crank damper on front. the contacts get corroded in these also. the unit is susceptible to damage by broken belts or road debris. i've seen them torn off and MIA. many mudders carry a spare under the seat.
also check the ICM ignition control module on pass. fender wall, contacts and plug, they get sprayed when a hose breaks at heater core. never seen a ICM fail internally on a 4L but possible.
i would only go Motorcraft, Standard or ACDelco for new.
RockAuto has the best price
Ignition (4.0L)
The Electronic Ignition System consists of an Ignition Coil, Ignition Control Module (ICM), and Crankshaft Position (CKP) Sensor. The Ignition Coil pack contains three separate coils, each driven by a separate coil-driven output from the ICM. Each coil controls two spark plugs.
With the Ignition Switch in START, battery voltage is applied to the Ignition Coil through the 16 (R/LG) wire and Fuse Link G. When the Ignition Switch is released to the RUN position, voltage is applied through the 16 (R/LG) wire.
When the engine is running:
l The CKP sensor senses the crankshaft position.
l The Sensor sends a signal to the ICM and the PCM.
l The PCM then sends a timing signal back to the ICM.
l The ICM switches current on and off to the three Ignition Coil primary circuits as determined by the PCM signal. The sequence is determined by the ICM.
l Each interruption of a primary current makes the secondary current produce an open circuit high voltage pulse which is transmitted directly to the spark plugs.
l Similar to the Distributor Ignition System, the Electronic Ignition System provides a base timing signal if the timing signal from the PCM is missing.
REFERENCE :For diagnostic information, refer to «Section 2A » of the Powertrain Control/Emissions Diagnosis Manual.
ignition system problems do not always set a code
The Engine Running Wiggle Test may be activated any time the engine is running.
1. Hook up a STAR Tester, VOM or Scan Tool as shown.
2. Key off.
3. Start the engine.
4. For STAR Tester or VOM, activate Self-Test, deactivate and reactivate Self-Test. DO NOT shut the engine off. You are now in the Engine Running Continuous Monitor DTM. For Scan Tool, enter DTM, then enter wiggle DTM.
5. Tap, move, and wiggle the suspect sensor and/or harness or drive the vehicle. When a fault is detected, a Continuous Memory DTC will be stored in memory. This will be indicated as follows depending on the type of equipment being used:
l Malfunction Indicator Lamp (MIL): Lights
l VOM: Needle Sweep
Last edited by 96_4wdr; Dec 17, 2007 at 02:30 PM.
Thread Starter
|
Lead Driver
Joined: Oct 2004
Posts: 8,062
Likes: 35
From: Central Oregon
Thanks, I will check these out, drives my nuts when the computer does not tell you what is going on. I have a 91 AWD Aero that I can rob parts from, I will stay away from the Ford parts counter, local parts supply is $75 for that coil.
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
Post Fiend
Joined: Oct 2005
Posts: 5,242
Likes: 0
From: Kiev, Ukraine
Bertha, check voltage supply of ECU, ECU power sup. relay, overvoltage relay.
Early OBD-I EEC-IV computers did not save power supply related codes... they had no these codes.... Your ECU probably switches on/off on run. Had this problem becouse of corroded connector....
Early OBD-I EEC-IV computers did not save power supply related codes... they had no these codes.... Your ECU probably switches on/off on run. Had this problem becouse of corroded connector....
