Unusual cam phaser issue?
03-12-2019, 02:55 AM
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Unusual cam phaser issue?
07 FX4 Crew. Mechanic diagnosed can phaser issues, mostly because it was common in the 5.4l. The problem is I have no ticking sounds or diesel idle sounds. It idles and runs smothe as silk. The real problem I have is shuddering during acceleration. At light to moderate accel, the engine starts to shudder. Mostly on highway, or in town driving: Once I get about 1900rpm, it acts like it’s missing, If I gas it, or let off, it will stop. But if I continue at the same pace (throttle) it will start to shake the engine like it’s tearing itself apart. I have replaced VVT solenoids, and a coil on cylinder that previously read a misfire code. Had previous signals for faulty O2 sensors, but they haven’t come back since I replaced the coil. Still runs rough at intermediate accel but won’t throw a code. If I floor it at 60, CEL blinks and then goes off. I suspect this is related to the O2 sensor. Q: where do I start? Considering replacing: rest of coils, plugs, clean/replace O2 sensors, clean throttle body, new HV oil pump, what should I start with? Vacuum via smoke machine is non issue. Thanks for help.
03-12-2019, 04:48 AM
#2
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You have a misfire condition occurring. Scan for code set to see which cylinder/s the misfire is occurring in.
From there you can do the procedures to determine what is causing it.
Pull COP on suspect cylinder and inspect closely. With COP uninstalled, remove the spark plug and inspect. Dedicated spark plug socket for this engine makes easier job of it. Check porcelain on spark plug for cracks and ensure gap is within spec.
You'll want to confirm correct coil and spark plug is installed. If condition of both appears good, reinstall spark plug and swap the coil with another cylinder and see what result you get. Torque plug to between 25-28 ft/lbs.
Misfire stays on that cylinder and doesn't follow the coil that was swapped, replace spark plug and test again.
If misfire moves with coil, try testing the coil with a spark tester, remove boot and spring, clean spade terminal at top of coil and install a new boot and spring. Small amount of dielectric grease at top/bottom of boot.
If misfire remains, next check will be your fuel injector.
Hoping it ends before this.
From there you can do the procedures to determine what is causing it.
Pull COP on suspect cylinder and inspect closely. With COP uninstalled, remove the spark plug and inspect. Dedicated spark plug socket for this engine makes easier job of it. Check porcelain on spark plug for cracks and ensure gap is within spec.
You'll want to confirm correct coil and spark plug is installed. If condition of both appears good, reinstall spark plug and swap the coil with another cylinder and see what result you get. Torque plug to between 25-28 ft/lbs.
Misfire stays on that cylinder and doesn't follow the coil that was swapped, replace spark plug and test again.
If misfire moves with coil, try testing the coil with a spark tester, remove boot and spring, clean spade terminal at top of coil and install a new boot and spring. Small amount of dielectric grease at top/bottom of boot.
If misfire remains, next check will be your fuel injector.
Hoping it ends before this.
03-12-2019, 06:19 AM
#3
Mark
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^^^ this^^^. a flashing CEL is a classic sign of a misfire condition.
03-12-2019, 08:39 AM
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Plugs
plugs seem like a logical first step. A bit worried about breaking them off, but I suppose sooner is better than later. That hopefully will solve the misfire under heavy acceleration that prompted the flashing CEL the one time. Still worried about the severe shudder under light acceleration though, could that be a result of bad plugs too? Seems weird that it would only happen at 1800 rpm
03-12-2019, 08:44 AM
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Mark
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plugs seem like a logical first step. A bit worried about breaking them off, but I suppose sooner is better than later. That hopefully will solve the misfire under heavy acceleration that prompted the flashing CEL the one time. Still worried about the severe shudder under light acceleration though, could that be a result of bad plugs too? Seems weird that it would only happen at 1800 rpm
03-12-2019, 08:45 AM
#7
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Count me in for the plugs/boots to address the misfire condition. These trucks shake like crazy when misfiring.
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03-12-2019, 08:46 AM
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Yes.. the shudder is most likely from mis-fires. You do not mention the mileage on the motor.. I would start with a fresh set of SP546 motorcraft plugs and a new set of boots and springs.. clean all COP contacts. Clean throttle body and MAF sensor with proper cleaners. Check the condition of your FPDM.
03-12-2019, 09:01 AM
#9
Mark
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03-12-2019, 09:19 AM
#10
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I agree with the others. Also, I would hesitate to use that mechanic again if they diagnose things based on common problems. A full timing job could cost you 2k-3k and it wouldn't have solved your problem