Another Misfire issue! (yes i researched) HELP PLEASE!
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Another Misfire issue! (yes i researched) HELP PLEASE!
New member here, been browsing for awhile just never cared to sign up to forums.
2003 Ford F150 Lariat SuperCrew Fx4 5.4L 175k miles
Well here is my problem from the roots. About 2 months ago this all started out as me noticing a slight misfire on a cold start-up/drive only, with a check engine code reading Misfire Cylinder 4 after warming up it ran fine. So after A LOT of research I decided I would tackle the project of changing my plugs/COPs myself since they prolly were original. I have wrenched on several different vehicles in my past and consider myself a decent mechanic. So I did just that, motocraft dg508 COPS x8 and Motocraft SP-479 Plugs x8 gapped at .054. Truck ran AWESOME for a month (i drive 40 miles a day just to work and back), no problems, great gas mileage increase, etc.
Soooooooo then the other day the gas station was out of 87 octane(what i always run) so I decided what the hell I'll just put 89 octane in it. Well I hop on the interstate and get 5 miles to the next exit and while taking off from the off ramp I notice a slight mis-fire again (still no code) well by the time I get home (2 miles from the off ramp) my check engine light not only comes on but is flashing at me and the mis-fire is just terrible, whole truck shaking, lack of power, etc. Get the scan tool out and bam again Misfire cylinder 4. And this is what I have done
-New fuel filter
-Took the cylinder 4 injector out cleaned it real good and swapped it to cylinder 1(to see if my code moves cylinders)
-All 8 injectors OHM resistance falls into category and also with a needle stethoscope I can hear all 8 injectors ticking.
-Took cylinder 4 (passenger rear on engine) plug out everything looks normal. Did a compression test and it falls in normal range and holds the pressure without leaking down.
-All 8 COPs are still in normal OHM resistance range
-Put some Seafoam in the tank and also pulled a vacuum line and let some run through the intake mani.
Since I did all of that, it is still misfiring terribly, but after a 10 mile trip or so I am no longer getting a check engine light after I reset it by pulling my negative cable.
Could this just be bad gas and I'm gonna have to let it run its course, also coincidence that it threw the same cylinder misfire code from before I did my tune up? I need some input/ help. Thanks -TJay
2003 Ford F150 Lariat SuperCrew Fx4 5.4L 175k miles
Well here is my problem from the roots. About 2 months ago this all started out as me noticing a slight misfire on a cold start-up/drive only, with a check engine code reading Misfire Cylinder 4 after warming up it ran fine. So after A LOT of research I decided I would tackle the project of changing my plugs/COPs myself since they prolly were original. I have wrenched on several different vehicles in my past and consider myself a decent mechanic. So I did just that, motocraft dg508 COPS x8 and Motocraft SP-479 Plugs x8 gapped at .054. Truck ran AWESOME for a month (i drive 40 miles a day just to work and back), no problems, great gas mileage increase, etc.
Soooooooo then the other day the gas station was out of 87 octane(what i always run) so I decided what the hell I'll just put 89 octane in it. Well I hop on the interstate and get 5 miles to the next exit and while taking off from the off ramp I notice a slight mis-fire again (still no code) well by the time I get home (2 miles from the off ramp) my check engine light not only comes on but is flashing at me and the mis-fire is just terrible, whole truck shaking, lack of power, etc. Get the scan tool out and bam again Misfire cylinder 4. And this is what I have done
-New fuel filter
-Took the cylinder 4 injector out cleaned it real good and swapped it to cylinder 1(to see if my code moves cylinders)
-All 8 injectors OHM resistance falls into category and also with a needle stethoscope I can hear all 8 injectors ticking.
-Took cylinder 4 (passenger rear on engine) plug out everything looks normal. Did a compression test and it falls in normal range and holds the pressure without leaking down.
-All 8 COPs are still in normal OHM resistance range
-Put some Seafoam in the tank and also pulled a vacuum line and let some run through the intake mani.
Since I did all of that, it is still misfiring terribly, but after a 10 mile trip or so I am no longer getting a check engine light after I reset it by pulling my negative cable.
Could this just be bad gas and I'm gonna have to let it run its course, also coincidence that it threw the same cylinder misfire code from before I did my tune up? I need some input/ help. Thanks -TJay
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Yes plugs were torqued at 28 ft/lbs, I use Chevron Techron. I've had nothing but good luck out of seafoam. But this isn't what the thread is about. Thanks for your opinion -TJay
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I did check yes but I could not really find any. I also read up on the EGR problems and attached a hose to the EGR valve and applied vaccium to it, the truck did die so from what I read that rules out clogged ports in the TB. Also I checked my voltage on the Dxxx sensor that is associated with the EGR system. The voltage rises and lowers as I apply vacuum to it. However, I read sitting there with no vaccume it should read 0-0.5 volts. It reads about 0.9 volts.
I'm beginning to think it is bad fuel. I drove it to work (20 miles) tonight and it didn't seem to be as bad as it was yesterday. Also, still no CEL. I'm going to finish fueling it up in the morning when I get off with some Chevron Techron.
I'm beginning to think it is bad fuel. I drove it to work (20 miles) tonight and it didn't seem to be as bad as it was yesterday. Also, still no CEL. I'm going to finish fueling it up in the morning when I get off with some Chevron Techron.
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From: Easton, Pa.
Two things you need to know.
Checking coils with a meter will not tell you much.
If a coil fails the PCM will pick it out as a hard fault and set a code concerning the coil it'self.
If a coil developes shorted turns, it is not a hard fault and will still work but cause drivabilty issues in OD under light throttle and not set a code.
You may have picked up a load of water in the gas.
I would try an alky based water clearing additive.
It will take some time for it to clear. Water falls to the bottom of the tank right where the pickup is and will take it in the most.
Aky combines with the water. While it reduces the power ability the gas will still fire. As you add more clean fuel, it eventually gets deluted and burned.
While using alky additive, the fuel mileage may drop until it's all cleared out. Reason this can happen is the alky releases extra oxygen the OX sensors detect. They then send a lean signal to the PCM to richen up the fuel injection amount as a correction.
Good luck.
Checking coils with a meter will not tell you much.
If a coil fails the PCM will pick it out as a hard fault and set a code concerning the coil it'self.
If a coil developes shorted turns, it is not a hard fault and will still work but cause drivabilty issues in OD under light throttle and not set a code.
You may have picked up a load of water in the gas.
I would try an alky based water clearing additive.
It will take some time for it to clear. Water falls to the bottom of the tank right where the pickup is and will take it in the most.
Aky combines with the water. While it reduces the power ability the gas will still fire. As you add more clean fuel, it eventually gets deluted and burned.
While using alky additive, the fuel mileage may drop until it's all cleared out. Reason this can happen is the alky releases extra oxygen the OX sensors detect. They then send a lean signal to the PCM to richen up the fuel injection amount as a correction.
Good luck.
Last edited by Bluegrass; Jan 19, 2012 at 08:41 PM.
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The 89 octane did have a 10% ethanol mixture in it. As all the fuel around here. I live on the MS gulf coast so no it isn't very cold lol And blue grass thanks for the input. I do experience the pro lemn in OD at light throttle but also in any other gear as I accelerated, but. I can feel it trying to pick up, then sputter and start missing. It does it throughout the rpm range.
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From: Easton, Pa.
After your sure there are no effects from water in the gas and you still have missfire, consider that one coil may have developed a shorted turns condition.
The resistance change is so small it can't be measured by a simple meter.
Reason is it affects the magnetic inductive performance and ability to raise 12 volts to 40,000.
When this happens the coil output voltage goes lower and can even be temperature sensitive.
Very often this condition won't set a code because it's not a hard failure.
During the time the fault may not be present even on a very short time basis, the program cancels the record so no code is set.
How the program checks for a hard missfire is every cylinder that fires is measured for crank rotation time by the crank sensor against a table of average rotation times for all cylinders. Doing it this way gives the program the ability to self adjust for age and wear.
The program can only associate it with either lack of fuel, or lack of ignition but cannot tell what the exact cause is.
The cylinder that has slow rotation time is known so a monitor that looks at the coil at the same time can be ided by association.
Any other cylinder power failure such as the plug, or injector is only ided as a slow rotation.
Associated with this is fuel with no ignition. This often flashes the CEL lamp as an alert that fuel may be burning in the cats causing possible permant damage by melting if allowed to go on too long.
Also check the crank sensor plug seating. If intermitant it will cause all kinds of missfire, lost of timing and fuel injection timing. PCM loses reference when it happens.
Last, look at the heater hoses over the #4 plug area for a leak.
Good luck.
The resistance change is so small it can't be measured by a simple meter.
Reason is it affects the magnetic inductive performance and ability to raise 12 volts to 40,000.
When this happens the coil output voltage goes lower and can even be temperature sensitive.
Very often this condition won't set a code because it's not a hard failure.
During the time the fault may not be present even on a very short time basis, the program cancels the record so no code is set.
How the program checks for a hard missfire is every cylinder that fires is measured for crank rotation time by the crank sensor against a table of average rotation times for all cylinders. Doing it this way gives the program the ability to self adjust for age and wear.
The program can only associate it with either lack of fuel, or lack of ignition but cannot tell what the exact cause is.
The cylinder that has slow rotation time is known so a monitor that looks at the coil at the same time can be ided by association.
Any other cylinder power failure such as the plug, or injector is only ided as a slow rotation.
Associated with this is fuel with no ignition. This often flashes the CEL lamp as an alert that fuel may be burning in the cats causing possible permant damage by melting if allowed to go on too long.
Also check the crank sensor plug seating. If intermitant it will cause all kinds of missfire, lost of timing and fuel injection timing. PCM loses reference when it happens.
Last, look at the heater hoses over the #4 plug area for a leak.
Good luck.
Last edited by Bluegrass; Jan 20, 2012 at 02:00 PM.
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I am having a similar issue on my 2006 SCREW w/112,000 miles. I have narrowed it down (at least in my head) to a intermittent coil or insulator problem. AS I can find no real way to test a coil that is "going" bad, i am going to buy 1 and swap it with a different cyclinder each day to find the culprit (if that is it).
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Turned out one of the new coils were bad I'm guessing. I switched number 4 out with one of my older coils and it's running good again.
But now.....is there something that could cause these coils to fail? Number 4 was originally the problem. Or is it a coincidence that the only new coil that failed is in the same cylinder as the previous failure?? *HEADACHE!*
But now.....is there something that could cause these coils to fail? Number 4 was originally the problem. Or is it a coincidence that the only new coil that failed is in the same cylinder as the previous failure?? *HEADACHE!*
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From: Easton, Pa.
Any new part can fail at anytime.
Trick is to keep an open mind so you don't block out a situation like this just because it was replaced.
Coils are a difficult item to control at mfgering, for life expectancy.
If they were made bullet proof they would cost even more than they do.
They are considered as a maintaince item dispite the cost.
It's a mind over matter thing.
Nobody thinks twice about replaceing tires that cost two or three times a coil cost x 4 and have a limited life usually much less than coils, on average.
The coil is machine wound on a bobbin form using enamel wire.
If wound to tight it can break at a terminal or winding rub-through at turns each lays against.
From heat expansion/contraction, the enamel wears through on one or more places in the winding and the turns becomes shorted. This fault has a huge effect on coil output voltage.
This is one of the big reasons to replace with OEM coils of at least a known quality level but then even they can fail at some point.
In addition, see where they live on a motor. Right behind the hot radiator, on hot heads and the effects of exhaust manifold heat espcially after engine shut down.
Good luck.
Trick is to keep an open mind so you don't block out a situation like this just because it was replaced.
Coils are a difficult item to control at mfgering, for life expectancy.
If they were made bullet proof they would cost even more than they do.
They are considered as a maintaince item dispite the cost.
It's a mind over matter thing.
Nobody thinks twice about replaceing tires that cost two or three times a coil cost x 4 and have a limited life usually much less than coils, on average.
The coil is machine wound on a bobbin form using enamel wire.
If wound to tight it can break at a terminal or winding rub-through at turns each lays against.
From heat expansion/contraction, the enamel wears through on one or more places in the winding and the turns becomes shorted. This fault has a huge effect on coil output voltage.
This is one of the big reasons to replace with OEM coils of at least a known quality level but then even they can fail at some point.
In addition, see where they live on a motor. Right behind the hot radiator, on hot heads and the effects of exhaust manifold heat espcially after engine shut down.
Good luck.
Thread Starter
|
Member
Joined: Jan 2012
Posts: 12
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Any new part can fail at anytime.
Trick is to keep an open mind so you don't block out a situation like this just because it was replaced.
Coils are a difficult item to control at mfgering, for life expectancy.
If they were made bullet proof they would cost even more than they do.
They are considered as a maintaince item dispite the cost.
It's a mind over matter thing.
Nobody thinks twice about replaceing tires that cost two or three times a coil cost x 4 and have a limited life usually much less than coils, on average.
The coil is machine wound on a bobbin form using enamel wire.
If wound to tight it can break at a terminal or winding rub-through at turns each lays against.
From heat expansion/contraction, the enamel wears through on one or more places in the winding and the turns becomes shorted. This fault has a huge effect on coil output voltage.
This is one of the big reasons to replace with OEM coils of at least a known quality level but then even they can fail at some point.
In addition, see where they live on a motor. Right behind the hot radiator, on hot heads and the effects of exhaust manifold heat espcially after engine shut down.
Good luck.
Trick is to keep an open mind so you don't block out a situation like this just because it was replaced.
Coils are a difficult item to control at mfgering, for life expectancy.
If they were made bullet proof they would cost even more than they do.
They are considered as a maintaince item dispite the cost.
It's a mind over matter thing.
Nobody thinks twice about replaceing tires that cost two or three times a coil cost x 4 and have a limited life usually much less than coils, on average.
The coil is machine wound on a bobbin form using enamel wire.
If wound to tight it can break at a terminal or winding rub-through at turns each lays against.
From heat expansion/contraction, the enamel wears through on one or more places in the winding and the turns becomes shorted. This fault has a huge effect on coil output voltage.
This is one of the big reasons to replace with OEM coils of at least a known quality level but then even they can fail at some point.
In addition, see where they live on a motor. Right behind the hot radiator, on hot heads and the effects of exhaust manifold heat espcially after engine shut down.
Good luck.