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I have a spark indicator light. Not sure if it would work in this application but basically you plug one end into the COP and the other onto your spark plug. Crank or start the engine and the indicator light between the COP and spark plug flashes if you're getting spark
So I cleaned up all the di-electric grease and unfortunately it did not make a difference. I read somewhere its possible that the PCM might be failing? Cam phasers? VCT?
Did you torque sparkplugs 25 to 28 foot pounds . Did you use anti seize and put it too near tip or use too much . Is it the high temp nickel . Old boots are a common problem . Are all connectors locking on . Did you disturb injector connectors . Is the PCM ground intact if you removed it .
Did you clean out tip area of hole with carb cleaner so as to remove carbon that breaks plugs going in and out .
Your failures are the back ones on each side ??? any chance you miss hooked them .
Did you torque sparkplugs 25 to 28 foot pounds . Did you use anti seize and put it too near tip or use too much . Is it the high temp nickel . Old boots are a common problem . Are all connectors locking on . Did you disturb injector connectors . Is the PCM ground intact if you removed it .
Did you clean out tip area of hole with carb cleaner so as to remove carbon that breaks plugs going in and out .
Your failures are the back ones on each side ??? any chance you miss hooked them .
Plugs are torqued, no antiseize used, not sure about the High temp nickel. Boots all looked fine, no signs of carbon traces. Made sure to listen for the click when putting the coil connections on. didn't move or disconnect the injectors at all and I did not touch the PCM or disconnect anything from it.
Did you torque sparkplugs 25 to 28 foot pounds . Did you use anti seize and put it too near tip or use too much . Is it the high temp nickel . Old boots are a common problem . Are all connectors locking on . Did you disturb injector connectors . Is the PCM ground intact if you removed it .
Did you clean out tip area of hole with carb cleaner so as to remove carbon that breaks plugs going in and out .
Your failures are the back ones on each side ??? any chance you miss hooked them .
Also, the wires are so short coming off of the harness its nearly impossible to hook them up incorrectly, all plugs went in smoothly by hand so didnt feel like there was anything on the threads
Just wanted to cover most major failure points . Not being there we have no knowledge of condition of wiring harness . Yes normally the harness connectors too tight to cross. It is very common to pull pcm changing plugs to get to 3 and 4 . You may have to reseat pcm plugs after cleaning them with contact cleaner . I'm sure they were under pressure while you were in there .
The only thing else that I can think of is the intake runner control back there , its job is to control intake air swirl for different loads . I haven't heard it causing misfires but it does affect performance . There has been a lot of linkage problems with it ,. It is a very difficult area to fix or see . Some have used their phones with a endoscope attachment to see the hoses and attachments.
I know its tight getting to plugs, injector wiring is often disturbed during change so it always is considered . Very interesting combination of cyl misfires .
Clean all connectors on cops with contact cleaner,that grease is non conductive, its job is to keep hi volts from tracking and boot from heat seizing to porcelain . A very small amount inside boot with Q-tip is all it takes . Keep it off metal electrical parts .
Gentlemen, I do not mean to suggest the points offered up here are not important ones. But also do not want the OP to go on a wild goose chase. I would just point out that _many_ suggestions in this thread are oriented toward items that will produce different DTCs( P0351 through P0358). The OP does not have any codes indicating an electrical failure in the primary or secondary of the coils, - OR injectors.
P0301 through P0304 is the result of a deviant cylinder acceleration value (ie: absence of sufficient crankshaft rotational speed acceleration following the PCM ignition event for that cylinder). The PCM even has a separate microprocessor in it (called the AICE) to facilitate this "High Data Rate" accurate monitoring of power balance, capable of detecting the slight crankshaft rotational acceleration that results from a normal ignition. Ref: Motorcraft Service Manual OBDII Theory of Operation, page 7-9 of 98. A quote from that section states in part:
------------
"The HDR Misfire Monitor uses a high data rate crankshaft position signal, (i.e. 18 position references per
crankshaft revolution [20 on a V-10]). This high-resolution signal is processed using two different algorithms. The
first algorithm, called pattern cancellation, is optimized to detect low rates of misfire. The algorithm learns the
normal pattern of cylinder accelerations from the mostly good firing events and is then able to accurately detect
deviations from that pattern. The second algorithm is optimized to detect “hard” misfires, i.e. one or more
continuously misfiring cylinders. This algorithm filters the high-resolution crankshaft velocity signal to remove some
of the crankshaft torsional vibrations that degrade signal to noise. This significantly improves detection capability for
continuous misfires. Both algorithms produce a deviant cylinder acceleration value, which is used in evaluating
misfire in the “General Misfire Algorithm Processing” section below."
--------------
The PCM is designed such that it can sense an OPEN or SHORT in the Coil Primary, and when the primary is 'de-energized', it is designed to sense the large reverse 'KICK' that occurs in the primary circuit when the secondary generates a 'spark' - producing current flow in the secondary - in EACH of THREE SUCCESSIVE STRIKES (below a certain RPM ~ 2500 rpm). It can be seen in the following scope trace.
The blue trace is 'current' in the primary circuit. The Yellow trace is 'voltage' on the primary.
If the PCM does not sense 'current' (or senses too much, or instantaneous current - a short) in the primary circuit, _AND_ the reverse 'kick', when it initiates an ignition event, it equals a P035X. The wild card here is if that 'spark' is NOT across the spark plug tip. ie: through a faulty boot, or crack in the ceramic inside the spark plug as suggested in previous posts. Then it would result in a P030X - because the primary test is satisfied but the AICE chip / algorithm does not detect normal crankshaft acceleration from the combustion. Much of that is based on the crankshaft tone ring, CKP sensor, proper cylinder aspiration (ie: cam phasers etc). However, those things would not discriminate against Cylinders 3,4 and 7,8.
I'm not suggesting that I know what's wrong. But don't want the OP to throw parts at the thing, but instead try trust what the PCM fault codes are telling us and try to out-smart the thing.
Something that could effect cylinder aspiration of rear cylinders, and thus proper combustion, of both banks could be exhaust back pressure. They would not be expelling exhaust as effectively as cylinders farther from plugged cats or exhaust. The OP has talked about flashing CEL. Which is an indication that catalyst damaging misfire rates are occurring and dumping excess fuel into the exhaust. They can not stand too much of that before catalyst melts, and they will still get hot if partially melted.
@nzwicker, if everything suggested in this thread has been done, it might be something to investigate. It's noisy, but a possibility is to remove both upstream O2 sensors and see if it effects the misfires.
Gentlemen, I do not mean to suggest the points offered up here are not important ones. But also do not want the OP to go on a wild goose chase. I would just point out that _many_ suggestions in this thread are oriented toward items that will produce different DTCs( P0351 through P0358). The OP does not have any codes indicating an electrical failure in the primary or secondary of the coils, - OR injectors.
P0301 through P0304 is the result of a deviant cylinder acceleration value (ie: absence of sufficient crankshaft rotational speed acceleration following the PCM ignition event for that cylinder). The PCM even has a separate microprocessor in it (called the AICE) to facilitate this "High Data Rate" accurate monitoring of power balance, capable of detecting the slight crankshaft rotational acceleration that results from a normal ignition. Ref: Motorcraft Service Manual OBDII Theory of Operation, page 7-9 of 98. A quote from that section states in part:
------------
"The HDR Misfire Monitor uses a high data rate crankshaft position signal, (i.e. 18 position references per
crankshaft revolution [20 on a V-10]). This high-resolution signal is processed using two different algorithms. The
first algorithm, called pattern cancellation, is optimized to detect low rates of misfire. The algorithm learns the
normal pattern of cylinder accelerations from the mostly good firing events and is then able to accurately detect
deviations from that pattern. The second algorithm is optimized to detect “hard” misfires, i.e. one or more
continuously misfiring cylinders. This algorithm filters the high-resolution crankshaft velocity signal to remove some
of the crankshaft torsional vibrations that degrade signal to noise. This significantly improves detection capability for
continuous misfires. Both algorithms produce a deviant cylinder acceleration value, which is used in evaluating
misfire in the “General Misfire Algorithm Processing” section below."
--------------
The PCM is designed such that it can sense an OPEN or SHORT in the Coil Primary, and when the primary is 'de-energized', it is designed to sense the large reverse 'KICK' that occurs in the primary circuit when the secondary generates a 'spark' - producing current flow in the secondary - in EACH of THREE SUCCESSIVE STRIKES (below a certain RPM ~ 2500 rpm). It can be seen in the following scope trace.
The blue trace is 'current' in the primary circuit. The Yellow trace is 'voltage' on the primary.
If the PCM does not sense 'current' (or senses too much, or instantaneous current - a short) in the primary circuit, _AND_ the reverse 'kick', when it initiates an ignition event, it equals a P035X. The wild card here is if that 'spark' is NOT across the spark plug tip. ie: through a faulty boot, or crack in the ceramic inside the spark plug as suggested in previous posts. Then it would result in a P030X - because the primary test is satisfied but the AICE chip / algorithm does not detect normal crankshaft acceleration from the combustion. Much of that is based on the crankshaft tone ring, CKP sensor, proper cylinder aspiration (ie: cam phasers etc). However, those things would not discriminate against Cylinders 3,4 and 7,8.
I'm not suggesting that I know what's wrong. But don't want the OP to throw parts at the thing, but instead try trust what the PCM fault codes are telling us and try to out-smart the thing.
Something that could effect cylinder aspiration of rear cylinders, and thus proper combustion, of both banks could be exhaust back pressure. They would not be expelling exhaust as effectively as cylinders farther from plugged cats or exhaust. The OP has talked about flashing CEL. Which is an indication that catalyst damaging misfire rates are occurring and dumping excess fuel into the exhaust. They can not stand too much of that before catalyst melts, and they will still get hot if partially melted.
@nzwicker, if everything suggested in this thread has been done, it might be something to investigate. It's noisy, but a possibility is to remove both upstream O2 sensors and see if it effects the misfires.
Thank you very much for the extremely detailed response. It was mentioned to me when I went by the local repair shop to check out the catalytic converters as well but I did not think to remove the o2 sensors. As I said prior, they both get hot when the truck gets up to temperature as well as the pipes right after them so it doesn't FEEL like they are clogged. would I get the same results if I just unplugged the sensors rather than removing them completely or does the circuit need to be complete? only reason I ask is because I live in northern Canada and exhaust tends to be very rusty at this age and kilometers (260,000 kms although I was told then engine was changed at 100k).
'IF' restricted exhaust flow is the problem, it is a hard to diagnose any way except put in a pressure gauge or 'relieve' the pressure somehow to see what happens. Might have to enlist the help of an exhaust shop.
I suggested the possibility looking for something common to the rear cylinders on both banks. Can't think of much else. Cam phasers will effect one bank or the other. Wiring harness' are bank by bank specific. Can't think of any reason PCM would discriminate against 3-4, 7-8.
Perhaps some of the other guys can come up with some other ideas or symptoms you could look for. I think plugged cats would generally effect upper end power most significantly - and I do believe restricted exhaust will cause MORE misfire troubles after the engine warms up. Might have to have a scanner to monitor misfire instances a little more closely.
We don't always get all the codes sent to us but if that's all there was he is very right . He has insight that most of us don't have . His in depth theory of operation is the best . We learn from him again . Just got my torque pro loaded on my new phone had to buy it again .
Are there codes for rich/lean condition on exhaust .
The o2 removal test is the way to go . I was at one point going to go to a muffler guy for a test on my cats but I found my problems elsewhere . So I did not get the experience in that area .
I do wonder about the intake manifold on this one as well as the tone ring and possible mech damage .
161k miles and engine has been replaced ." (plugs)I changed them 2 days ago, prior to that I do not know as I just recently purchased this truck". Has he had the truck long enough to see it run good under load before this failure . . New/used or reman was it done right . Or was it a failed timing job . Does the op have a code reader , maybe time to get the bluetooth adapter and torque pro for the android phone .
03-23-2018, 05:18 PM
