5.4 Surges wildly when warm
11-22-2017, 10:46 AM
#1
5.4 Surges wildly when warm
My conventional methods have been unsuccessful...so I found this forum, and hoping someone here will shed some light..
Background - 2007 F150 5.4 with Flex Fuel - 128K miles.
Recently purchased this truck. Had a few DTC's on - Lean Code, IRC stuck, and a few misfire codes. Replaced the plugs with a 1 piece design, fixed an exhaust leak, replaced one stuck open injector, and of course replaced the intake runner controller.
After all this, truck ran great with no more DTC's. Although, I didnt really drive it for long periods of time after the work was completed. Drove the truck a few days ago for a longer than normal drive, and the truck started surging under a load, just slightly. Long story short, when the truck is cold, it runs like a top. As the truck warms up, the surging gets progressively worse until its considerably,...well..terrible. With foot steady, it will surge 2-300 rpms up and down at a constant frequency. This is not the torque converter. There are zero DTC's. Does not do it in N, just when driving. Doesnt matter what gear the truck is in, either.
Had a good mechanic friend go for a ride with me, reading live data from OBD. 15 minutes in, and most everything looked good according to him, with the exception of the Variable Valve Timing. He said it was swinging fairly wildly.. Left the truck with him and he will be looking into it further. Have always owned GM products.. so my knowledge of the modular motors is limited.. Here was my thoughts.. If the valve timing is driven off oil pressure...could this be as simple as the wrong oil and/or my pressure below par? Unsure as to how sensitive they are to those things. Thinking the dash gauge for oil pressure is more or less a dummy gauge? Again, could be wrong?? Thoughts appreciated to calm this bucking bronco..
Background - 2007 F150 5.4 with Flex Fuel - 128K miles.
Recently purchased this truck. Had a few DTC's on - Lean Code, IRC stuck, and a few misfire codes. Replaced the plugs with a 1 piece design, fixed an exhaust leak, replaced one stuck open injector, and of course replaced the intake runner controller.
After all this, truck ran great with no more DTC's. Although, I didnt really drive it for long periods of time after the work was completed. Drove the truck a few days ago for a longer than normal drive, and the truck started surging under a load, just slightly. Long story short, when the truck is cold, it runs like a top. As the truck warms up, the surging gets progressively worse until its considerably,...well..terrible. With foot steady, it will surge 2-300 rpms up and down at a constant frequency. This is not the torque converter. There are zero DTC's. Does not do it in N, just when driving. Doesnt matter what gear the truck is in, either.
Had a good mechanic friend go for a ride with me, reading live data from OBD. 15 minutes in, and most everything looked good according to him, with the exception of the Variable Valve Timing. He said it was swinging fairly wildly.. Left the truck with him and he will be looking into it further. Have always owned GM products.. so my knowledge of the modular motors is limited.. Here was my thoughts.. If the valve timing is driven off oil pressure...could this be as simple as the wrong oil and/or my pressure below par? Unsure as to how sensitive they are to those things. Thinking the dash gauge for oil pressure is more or less a dummy gauge? Again, could be wrong?? Thoughts appreciated to calm this bucking bronco..
11-22-2017, 10:56 AM
#2
Moderator
Yes the oil pressure gauge is just a dummy light. You're correct there. A lot of times with these engines a surge or stutter at speed is a misfire. You did good changing the plugs, next I would suggest changing the boots and springs on the coil packs. Relatively cheap ($40) and simple. You just need to remove the coils, clean the point where the spring makes contact with the coil. Put on the new spring, then put a little dielectric grease on the boot but make sure to not get much if any of the grease on the point of contact. The grease does not conduct electricity so it is just used to seal out moisture. Then put a little dielectric grease on the inside of the boot where it will contact the plug but again try not to get any on the spring or where the spring will contact the top of the plug. Then put it back on. This has fixed ALL of my misfires to date and has worked for may others on here including many with similar symptoms as you. Sometimes the misfires are not enough to throw a code. You can usually see them by looking at live data and a misfire count in (I think) a mode 6 test.
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Boscosz28 (11-22-2017)
11-22-2017, 10:56 AM
#3
Try changing coil packs (or boots and springs) if not....it could be VCT solenoids. Either stuck open or pick-up screens are clogged...causing a surge of oil
11-22-2017, 11:49 AM
#4
Senior Member
Could this be a clogged fuel filter? An engine starving for fuel might do this and it would not do it in neutral because not as much fuel would be needed. Even if that is not it it wouldn't hurt to change it if you don't know how old it is.
11-22-2017, 12:09 PM
#5
Yes the oil pressure gauge is just a dummy light. You're correct there. A lot of times with these engines a surge or stutter at speed is a misfire. You did good changing the plugs, next I would suggest changing the boots and springs on the coil packs. Relatively cheap ($40) and simple. You just need to remove the coils, clean the point where the spring makes contact with the coil. Put on the new spring, then put a little dielectric grease on the boot but make sure to not get much if any of the grease on the point of contact. The grease does not conduct electricity so it is just used to seal out moisture. Then put a little dielectric grease on the inside of the boot where it will contact the plug but again try not to get any on the spring or where the spring will contact the top of the plug. Then put it back on. This has fixed ALL of my misfires to date and has worked for may others on here including many with similar symptoms as you. Sometimes the misfires are not enough to throw a code. You can usually see them by looking at live data and a misfire count in (I think) a mode 6 test.
Correct. It actually looked very new. I crawled under there and pulled it off and it was good to go!
11-22-2017, 03:55 PM
#6
Mark
iTrader: (1)
Check the condition of your Fuel Pump Driver Module FPDM located above your spare tire ..usually corroded to the frame. The back side of the module cracks open and will cause surging..stalling and other weird stuff. If the FPDM checks out.. look at the fuel purge vent solenoid.
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Boscosz28 (11-22-2017)
11-22-2017, 04:00 PM
#7
Senior Member
Back to a fuel issue, check your FPDM (Fuel pump dirver module) for corrosion or damage. It can cause fuel pressure fluctuations that don't necessarily trip a code. Edit: tech beat me to it.
Last edited by tcp2; 11-22-2017 at 04:03 PM.
The following users liked this post:
Boscosz28 (11-22-2017)
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11-22-2017, 04:02 PM
#8
Check the condition of your Fuel Pump Driver Module FPDM located above your spare tire ..usually corroded to the frame. The back side of the module cracks open and will cause surging..stalling and other weird stuff. If the FPDM checks out.. look at the fuel purge vent solenoid.
Back to a fuel issue, check your FPDM (Fuel pump dirver module) for corrosion or damage. It can cause fuel pressure fluctuations that don't necessarily trip a code. Edit: tech beat me to it.
FPDM change
FPDM change
11-23-2017, 04:02 AM
#9
Senior Member
The misfire data by cylinder can be seen through the mode 6 data as the other post suggested.
In order for the "Misfire Monitoring" PID to be active, a 'drive cycle" must be completed.
The Misfire Monitoring requires you to do 3 times..........decel from 60+ mph down to 40- mph without touching the gas during the deceleration process.
This is part of the necessary data the parameter needs in order to complete its evaluation and all of the accessible data be displayed.
If you see a P1000 code, it simply means that all of the "drive cycle" requirements were not met in order for all Mode6 data to be complete and accurate.
It sounds crazy maybe, but, it is how the PCM operates its diagnostic procedure.
I've chased a intermittent / random misfire for a month now and this was how I found the problem cylinder as it might only misfire three or four times on a 30 min drive.
One thing to check in you trouble shooting which is what was causing my misfire.
Inside the plug/electrical connector or Male side of the connection, there are two Female holes. If you look behind them, there is a rubber gasket that seals the connection and prevents vibration as well. The gasket had came out of it's seat and was pushed up into the back of the plug and was preventing a proper "mating" of the connection causing the misfire.
Used a O Ring tool to fish it out and reseat it. I found two others that were not properly seated as well.
They seem to dry out over time so, I took the three I found with issues completely out, cleaned them off, reinstalled, and used a toothpick to apply a tiny amount of dielectric grease just on the rubber, to help the housing slide around it and not "drag" it from it's proper seat.
If you can identify the cylinder/s, then you can pursue other means of diagnosing the problem. I highly recommend getting the diagnostic data before throwing parts at it and hoping for a fix.
Good luck and keep us posted.
In order for the "Misfire Monitoring" PID to be active, a 'drive cycle" must be completed.
The Misfire Monitoring requires you to do 3 times..........decel from 60+ mph down to 40- mph without touching the gas during the deceleration process.
This is part of the necessary data the parameter needs in order to complete its evaluation and all of the accessible data be displayed.
If you see a P1000 code, it simply means that all of the "drive cycle" requirements were not met in order for all Mode6 data to be complete and accurate.
It sounds crazy maybe, but, it is how the PCM operates its diagnostic procedure.
I've chased a intermittent / random misfire for a month now and this was how I found the problem cylinder as it might only misfire three or four times on a 30 min drive.
One thing to check in you trouble shooting which is what was causing my misfire.
Inside the plug/electrical connector or Male side of the connection, there are two Female holes. If you look behind them, there is a rubber gasket that seals the connection and prevents vibration as well. The gasket had came out of it's seat and was pushed up into the back of the plug and was preventing a proper "mating" of the connection causing the misfire.
Used a O Ring tool to fish it out and reseat it. I found two others that were not properly seated as well.
They seem to dry out over time so, I took the three I found with issues completely out, cleaned them off, reinstalled, and used a toothpick to apply a tiny amount of dielectric grease just on the rubber, to help the housing slide around it and not "drag" it from it's proper seat.
If you can identify the cylinder/s, then you can pursue other means of diagnosing the problem. I highly recommend getting the diagnostic data before throwing parts at it and hoping for a fix.
Good luck and keep us posted.
11-23-2017, 04:11 AM
#10
Senior Member
Also,
did you torque the plugs on install?
If not, you need to do so. Spec is 23-27lbs. I did all of mine at 26.5.lbs.
These trucks are super picky about secondary ignition components and installation. The plugs have a tendency of coming loose and getting "blow by" of exhaust/unburnt fuel so, proper torque is imperative.
What brand and number plugs did you use? Motorcraft and Champion seem to be the two brands with the most sucess. SP546 is latest MC Updated version.
You should also do (very important) a reset of all adaptive learning parameters when doing any work/replacement of parts. This will allow the PCM to adjust the fuel trims, shift points ect for the new components. It will help idle and shifting parameters as well.
It goes unmentioned most times but, is an important step to ensure the PCM recognizes and compensates for the new components operation v/s the old and adjusts adaptive learning parameters accordingly.
It would eventually catch up and do the same thing, but, if it's been 10 years since a reset, it'd probably take about that long to catch up so, best to take 5 mins and reset it yourself and get results instantly.
did you torque the plugs on install?
If not, you need to do so. Spec is 23-27lbs. I did all of mine at 26.5.lbs.
These trucks are super picky about secondary ignition components and installation. The plugs have a tendency of coming loose and getting "blow by" of exhaust/unburnt fuel so, proper torque is imperative.
What brand and number plugs did you use? Motorcraft and Champion seem to be the two brands with the most sucess. SP546 is latest MC Updated version.
You should also do (very important) a reset of all adaptive learning parameters when doing any work/replacement of parts. This will allow the PCM to adjust the fuel trims, shift points ect for the new components. It will help idle and shifting parameters as well.
It goes unmentioned most times but, is an important step to ensure the PCM recognizes and compensates for the new components operation v/s the old and adjusts adaptive learning parameters accordingly.
It would eventually catch up and do the same thing, but, if it's been 10 years since a reset, it'd probably take about that long to catch up so, best to take 5 mins and reset it yourself and get results instantly.
