SuzysJ
NAXJA Forum User
- Location
- corpus christi, texas
2001 4.0/AW4 2WD with 122,000 miles. I've searched every thread here and other JEEP forums, and am looking for anything I might have overlooked; thanks for any help.
Have had 0301 code awhile, and now has worsened. I changed the sparkplugs (stock Champ 12's), cleared codes and had a smooth idle. Fluids and filters are new or close. Took it for a gentle 12-mile highway run, and, on return, really stood on it and wound it out. Back to flashing CEL and rough running. This JEEP, though bought used, has had excellent maintenance. BUT, due to underhood heat, everything has gone crispy brittle. You touch it, it breaks/crumbles. (Finally raised hood rear with spacers and trimmed weatherstrip awhile back, no longer have to use gloves to open hood). Have replaced one vacuum line that was history, and taped over terminations that were dry-rotted on another.
Went by Autozone and the mighty ACTRON scanner pulled, in this sequence:
0201
0300
0301
0304
(info from the site: http://www.obd-codes.com/)
0201 Cylinder 1 Injector Circuit Malfunction
FUEL OR AIR CIRCUITRY
The symptoms for this code will likely be a misfire and a rough running engine. Poor acceleration. The MIL will also be illuminated.
The causes could be any of the following:
• Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes
• Open in the wiring to the injector
• Short in the wiring to the injector
• Bad PCM
0300 Random/Multiple Cylinder Misfire Detected
IGNITION CIRCUITRY
Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.
• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present
A code P0300 may mean that one or more of the following has happened:
• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Faulty camshaft position sensor
• Defective computer
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor.
0301 Cylinder #1 Misfire Detected
IGNITION CIRCUITRY
0304 Cylinder #4 Misfire Detected
(Same as above)
None of this appears unusual, the "problem" I am having is that in order to make inspections I have to count on doing replacements of about anything I touch. No joke. I want to minimize the items I check.
After replacing spark plugs I checked/jiggled wire connections to injectors. Now for questions:
1] Should injectors rotate easily, or is this evidence of O-ring deterioration? I have no leaks.
2] Injector wiring has a red stay-clip. I moved it up and expected to be able to remove from injector. Seems the harness termination is welded in place. Tried several methods of removal, but no luck.
3] I would like to be able to examine the injector harness under the long plastic cover, but it won't survive being removed. Any point in checking? I examined a photo from another site where a wire was chafed, appeared to be on harness back near firewall and had rubbed on an engine fastener. My harness has no interference at that spot.
4] I assume I will be replacing the injectors at some point soon (5.0 Motorsports) and may have to replace the injector harness as well. PCM, too? (Crunchy connectors)
4] Vacuum leaks. Hate them, almost as much as electrical shorts under the dash; been chasing them nearly forty years. I know to check the lines connected to intake manifold. Have replaced fuel purge solenoid line/harness. Any other "weird" places to check? I don't really want to disassemble entire system if a known place is problematical.
5. When this JEEP was purchased [4] years ago last month, I pulled/cleaned TB and replaced MAP and TPS as preventative maintenance. I am leaning towards heat degradation here, and wonder if anyone has insight to this area as to leaks. I'll try fogging it, as the vacuum leak are the worst problem being experienced.
6. I have seen the MOTORAGE .pdf on re-aligning the cam position sensor, somewhere it was suggested that this may go whacky based on some timing chain stretch. I "might" do this as preventative/good practice, but assume will buy new as, again, anything I touch crumbles.
Your insights appreciated.
:worship:
Have had 0301 code awhile, and now has worsened. I changed the sparkplugs (stock Champ 12's), cleared codes and had a smooth idle. Fluids and filters are new or close. Took it for a gentle 12-mile highway run, and, on return, really stood on it and wound it out. Back to flashing CEL and rough running. This JEEP, though bought used, has had excellent maintenance. BUT, due to underhood heat, everything has gone crispy brittle. You touch it, it breaks/crumbles. (Finally raised hood rear with spacers and trimmed weatherstrip awhile back, no longer have to use gloves to open hood). Have replaced one vacuum line that was history, and taped over terminations that were dry-rotted on another.
Went by Autozone and the mighty ACTRON scanner pulled, in this sequence:
0201
0300
0301
0304
(info from the site: http://www.obd-codes.com/)
0201 Cylinder 1 Injector Circuit Malfunction
FUEL OR AIR CIRCUITRY
The symptoms for this code will likely be a misfire and a rough running engine. Poor acceleration. The MIL will also be illuminated.
The causes could be any of the following:
• Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes
• Open in the wiring to the injector
• Short in the wiring to the injector
• Bad PCM
0300 Random/Multiple Cylinder Misfire Detected
IGNITION CIRCUITRY
Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.
• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present
A code P0300 may mean that one or more of the following has happened:
• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Faulty camshaft position sensor
• Defective computer
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor.
0301 Cylinder #1 Misfire Detected
IGNITION CIRCUITRY
0304 Cylinder #4 Misfire Detected
(Same as above)
None of this appears unusual, the "problem" I am having is that in order to make inspections I have to count on doing replacements of about anything I touch. No joke. I want to minimize the items I check.
After replacing spark plugs I checked/jiggled wire connections to injectors. Now for questions:
1] Should injectors rotate easily, or is this evidence of O-ring deterioration? I have no leaks.
2] Injector wiring has a red stay-clip. I moved it up and expected to be able to remove from injector. Seems the harness termination is welded in place. Tried several methods of removal, but no luck.
3] I would like to be able to examine the injector harness under the long plastic cover, but it won't survive being removed. Any point in checking? I examined a photo from another site where a wire was chafed, appeared to be on harness back near firewall and had rubbed on an engine fastener. My harness has no interference at that spot.
4] I assume I will be replacing the injectors at some point soon (5.0 Motorsports) and may have to replace the injector harness as well. PCM, too? (Crunchy connectors)
4] Vacuum leaks. Hate them, almost as much as electrical shorts under the dash; been chasing them nearly forty years. I know to check the lines connected to intake manifold. Have replaced fuel purge solenoid line/harness. Any other "weird" places to check? I don't really want to disassemble entire system if a known place is problematical.
5. When this JEEP was purchased [4] years ago last month, I pulled/cleaned TB and replaced MAP and TPS as preventative maintenance. I am leaning towards heat degradation here, and wonder if anyone has insight to this area as to leaks. I'll try fogging it, as the vacuum leak
6. I have seen the MOTORAGE .pdf on re-aligning the cam position sensor, somewhere it was suggested that this may go whacky based on some timing chain stretch. I "might" do this as preventative/good practice, but assume will buy new as, again, anything I touch crumbles.
Your insights appreciated.
:worship: