Stuttering/Hesitation
Thread Starter
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Mountain Pass
Joined: Sep 2003
Posts: 111
Likes: 1
From: South Texas
Stuttering/Hesitation
I've only owned a 6.0 for about 10 months now. I have a 2005 SCab FX4 with 125,000 miles on it. It has an Airaid cold air intake and MBRP exhaust without a muffler, everything else is stock. The stuttering/hesitation starts at about 1500 rpm, is worst at 1600rpm and seem so to go away at 2000rpm. It also seems to hesitate when I barely press the gas pedal while driving. Based on other fuel issues with other vehicles, I would assume this is a fuel problem, but am not well versed in the 6.0 engines. Fuel filters were said to be good by the dealership about 10,000 miles ago. EGR valve was replaced last week. I'm not blowing smoke of any color, even at WOT. I was thinking an injector may be the issue, but I show no other symptoms besides the hesitation/vibration. I don't feel any lack of power when I give it full throttle. I would like to know a definitive way to diagnose the problem without going to the stealership. Thanks in advance for your input!
Postmaster
Joined: Aug 2015
Posts: 3,910
Likes: 18
From: NW IA
A definitive way to diagnose is to get something to read live data and show any codes you have.
FYI........those fuel filters, while not likely the issue, are due for a change at 10k miles. Funny the dealer didn't say anything, they should know if it's a Ford dealer.
FYI........those fuel filters, while not likely the issue, are due for a change at 10k miles. Funny the dealer didn't say anything, they should know if it's a Ford dealer.
Postmaster
Joined: Aug 2015
Posts: 3,910
Likes: 18
From: NW IA
Here are some numbers that might help the forum
At WOT, what are your readings for
ICP
IPR
Boost
Also, at hot idle what do you have for ICP and IPR?
I would, for starters, replace the fuel filters since they have at least 10k miles on them.
Could be a fuel issue, but also sounds like it might be turbo slow to spool up perhaps
At WOT, what are your readings for
ICP
IPR
Boost
Also, at hot idle what do you have for ICP and IPR?
I would, for starters, replace the fuel filters since they have at least 10k miles on them.
Could be a fuel issue, but also sounds like it might be turbo slow to spool up perhaps
Senior User
Joined: Feb 2017
Posts: 117
Likes: 0
From: Shreveport, LA
Start the engine, pop the hood and climb in. Wiggle the injector harness at each injector. If the stutter gets better/worse, you found your issue. If not, it cost you 5 minutes and no dollars.
Fleet Mechanic
Joined: Nov 2016
Posts: 1,343
Likes: 94
If you have an ipad laying around, purchase the Forscan app online. Then get a wifi adapter that plugs into the obd2 port. Amazon has them I bet some electronic shops do as well.
Play around with the app, it should give you cylinder misfires. We have had this same symptom and it was an injector going bad.
Other things can be going wrong as well, but this helps point to a single cylinder or multicylinder issue.
Really fun tool to play with and monitor the health of the engine.
Play around with the app, it should give you cylinder misfires. We have had this same symptom and it was an injector going bad.
Other things can be going wrong as well, but this helps point to a single cylinder or multicylinder issue.
Really fun tool to play with and monitor the health of the engine.
Thread Starter
|
Mountain Pass
Joined: Sep 2003
Posts: 111
Likes: 1
From: South Texas
Here are some numbers that might help the forum
At WOT, what are your readings for
ICP
IPR
Boost
Also, at hot idle what do you have for ICP and IPR?
I would, for starters, replace the fuel filters since they have at least 10k miles on them.
Could be a fuel issue, but also sounds like it might be turbo slow to spool up perhaps
At WOT, what are your readings for
ICP
IPR
Boost
Also, at hot idle what do you have for ICP and IPR?
I would, for starters, replace the fuel filters since they have at least 10k miles on them.
Could be a fuel issue, but also sounds like it might be turbo slow to spool up perhaps
I replaced the fuel filters last night, but didn't fix the stuttering. It did improve the response though.
What is the recommended intervals to change the fuel filters? I know the manual says around 30k, but several of y'all said that if it has 10k to replace it.
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Thread Starter
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Mountain Pass
Joined: Sep 2003
Posts: 111
Likes: 1
From: South Texas
If you have an ipad laying around, purchase the Forscan app online. Then get a wifi adapter that plugs into the obd2 port. Amazon has them I bet some electronic shops do as well.
Play around with the app, it should give you cylinder misfires. We have had this same symptom and it was an injector going bad.
Other things can be going wrong as well, but this helps point to a single cylinder or multicylinder issue.
Really fun tool to play with and monitor the health of the engine.
Play around with the app, it should give you cylinder misfires. We have had this same symptom and it was an injector going bad.
Other things can be going wrong as well, but this helps point to a single cylinder or multicylinder issue.
Really fun tool to play with and monitor the health of the engine.
I will definitely check into that!
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Thread Starter
|
Mountain Pass
Joined: Sep 2003
Posts: 111
Likes: 1
From: South Texas
Here are some numbers that might help the forum
At WOT, what are your readings for
ICP
IPR
Boost
Also, at hot idle what do you have for ICP and IPR?
I would, for starters, replace the fuel filters since they have at least 10k miles on them.
Could be a fuel issue, but also sounds like it might be turbo slow to spool up perhaps
At WOT, what are your readings for
ICP
IPR
Boost
Also, at hot idle what do you have for ICP and IPR?
I would, for starters, replace the fuel filters since they have at least 10k miles on them.
Could be a fuel issue, but also sounds like it might be turbo slow to spool up perhaps
ICP at WOT was 2050psi
IPR at WOT was 46-49%
Injector Control Pressure Desired at WOT was 1902psi
ICP at hot idle was 581psi
IPR at hot idle was 23%
Injector Control Pressure Desired at hot idle was 580psi
No engine misfires detected during the live scan
Laughing Gas
Joined: Feb 2016
Posts: 817
Likes: 27
Your WOT numbers are off. Should be around 3800 ICP and 80+% IPR.
Something is wacko with the desired value. I don't know what goes into the calc but, when you find out, I'd start there.
Edit: FICM also a candidate for rework.
Something is wacko with the desired value. I don't know what goes into the calc but, when you find out, I'd start there.
Edit: FICM also a candidate for rework.
Thread Starter
|
Mountain Pass
Joined: Sep 2003
Posts: 111
Likes: 1
From: South Texas
It's been raining here for the last few days, so maybe I didn't quite hit it 100%. I'll check again once the rain stops, which should be by the weekend
Postmaster
Joined: Aug 2015
Posts: 3,910
Likes: 18
From: NW IA
Hot idle is right on the money, since the truck is not short on power doubt it's a HPO leak. Try running it with the ICP unplugged once and see if the stutter goes away.
I don't know much about the Bosch readers, maybe it didn't pick up the codes.
Forscan is a better choice and it's free. Just need to get an OBDII reader for the bluetooth aspect.
And yes, FICM is needing some love when it's touching 45%
Thread Starter
|
Mountain Pass
Joined: Sep 2003
Posts: 111
Likes: 1
From: South Texas
Def something goofy with those WOT numbers.
Hot idle is right on the money, since the truck is not short on power doubt it's a HPO leak. Try running it with the ICP unplugged once and see if the stutter goes away.
I don't know much about the Bosch readers, maybe it didn't pick up the codes.
Forscan is a better choice and it's free. Just need to get an OBDII reader for the bluetooth aspect.
And yes, FICM is needing some love when it's touching 45%
Hot idle is right on the money, since the truck is not short on power doubt it's a HPO leak. Try running it with the ICP unplugged once and see if the stutter goes away.
I don't know much about the Bosch readers, maybe it didn't pick up the codes.
Forscan is a better choice and it's free. Just need to get an OBDII reader for the bluetooth aspect.
And yes, FICM is needing some love when it's touching 45%
Postmaster
Joined: Aug 2015
Posts: 3,910
Likes: 18
From: NW IA
Passenger side valve cover on your model year, right by the glow plug module.
Unplug it and see if it runs any different, it's a quick and easy step, won't hurt a thing. The PCM just uses a set of default values while it's unplugged.
See if there is any oil residue on the sensor and the pigtail/plug. Don't worry if it trips a code, you can just reset it with Forscan
Unplug it and see if it runs any different, it's a quick and easy step, won't hurt a thing. The PCM just uses a set of default values while it's unplugged.
See if there is any oil residue on the sensor and the pigtail/plug. Don't worry if it trips a code, you can just reset it with Forscan