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Discussion Starter #1 (Edited)
Stuttering Under Load-Update

:frown2:Hi All,

This past spring while I was on a trip to Texas my 04 F250 developed a stutter/miss during low RMP loaded (high gear) driving. Looking at the Scangauge during driving, I see good boost during the hill climbs and when you'd expect it. Since it was a sudden change in performance I originally thought it was a fuel issue from one of the strange stations I had stopped at, as it acts just like a bad fuel filter on a gas engine. So when I got home, I changed the fuel filters. No change in performance.
I'm also getting some strange issues at start up (randomly) where the engine will sound like it's going to die and lope very badly (emitting an noxious odor but no significant amount of smoke).
Then I put in some AR9100 and it seemed to help very slightly on stutter under load.
Then I hooked up the Autoenginuity tool and got a bunch of pending codes, but nothing hard (KOEO). Haven't done the KOER, but suspect injector issues (replaced 4 when I put new heads on back in Oct of 2014 and now have 250K miles on truck), so will have to run the cylinder contribution test to figure out which ones.



So I finally got my fuel pressure set-up put back together and drove it. The idle fuel pressure was close to 60 psi and the WOT fuel pressure dropped to ~42psi and then came back up as engine RPM and initial acceleration load decreased.

  1. To me, it seems like the fuel being supplied to the regulator isn't strong enough to keep the pressure up during large fuel needs.
  2. Probably some injector damage from fuel starvation and possibly lots of miles on remaining 4 injectors.
  3. Possibly weak fuel pump.
  4. Possibly something clogging the fuel pick-up in the tank.
Pulled the tank and nothing going on there.
Have any of you seen the fuel regulator cause the pressure to fluctuate like I'm seeing? Do you think it is the fuel pump?


Thanks!
 

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It could be either the regulator OR the fuel pump. Sometimes the regulator parts wear and weaken over time.

It is acting like mine did when the pump started going out, but a new spring kit is cheaper than the pump. Unless you have the updated regulator spring (blue spring upgrade), then that is probably what I would start with.
 

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Discussion Starter #3
Thanks bismic!

After pulling the tank, I noticed all kinds of rear end lube being slung out of the pinion seal (strange that I didn't see a leak on the ground). Headed down to the dealer to get another seal and while I'm there I'll get another blue spring upgrade. The blue spring upgrade I originally installed was from one of the aftermarket guys, and I'm not sure of it's pedigree.
 

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Discussion Starter #4
I put a new fuel pump in and it appears that after all of the air was bled out of the system, it's holding at 60psi. During hard stops (with 6 gallons of fuel in the tank) it seems to fluctuate around 55psi to 60 psi at the stop. I assume the pressure fluctuation at stop is air getting into the line when all of the fuel runs to the front of the tank. After takeoff from a full stop at wide open throttle, I get at most a 5 psi drop from 60 all the way up to 70mph. I'm thinking the regulator is good for now. I was getting the stuttering quite badly when the engine was cold, but it settled down a bit when it warmed up.

I'm going to go fill the tank and then get back to reading DTCs and running the cylinder contribution test.

Stay tuned for more.
 

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Discussion Starter #5
Here's what I found when I connected the Auto Enginuity system to the truck:

DTCs shown on attached picture.

Looks like issues with the overhead that I'll have to fix later.
#3 Glow Plug Circuit looks like it's got some issue.
Generator Control Circuit - I got no Idea....

I also ran the Power Balance Test and got a perfectly straight line at 0 meaning no deviation at all between any of the cylinders....

I could really use some thoughts on what to try next.

Thanks!
 

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You have dual alternators?
 

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Discussion Starter #7
Hey Mark,

I do have dual alternators. Looks like the control circuitry for the second one is messed up. Could this be causing the stuttering and jerking?
It is worse when the motor is cold, but it doesn't go away when it gets hot.

Thank You for your help!
 

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Hard to say, but if the voltage is low, it can cause odd problems.

P0620:
Alternator code (in a dual alternator configuration) - often times it is not indicative of any significant issue. The PCM has fault detection circuitry which monitors the state of the generator turn on signal circuit. If the fault detection circuit senses a voltage other than what is expected, this DTC will set. The voltage regulator also contains fault detection circuitry. If the regulator detects a problem, the regulator will ground the generator turn on signal circuit, pulling the voltage low. This also causes the PCM to set the DTC.
- Failed Generator/Belt
- Battery charge
- PCM controlled generator
- PCM failure
- Open or short generator circuit

Regarding the glow plug code:
Sometimes a single glow plug code means the glow plug is bad. Sometimes it means the GPCM is bad.
 

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I have a 2004 F450 that had loaded misfire f or a long time and many repairs and trips to dealer. For a long time I pursued tire balance and some other issues as the problem sort of felt like road or tire issues. Only happened when towing and under a load--accelerating with no downshift or pulling a hill.
Three injectors were replaced at to times by dealer under warranty with no change.
Anyway, I decided it was a misfire as driving in a few places where there was a wall I could hear it in exhaust with window open under pull next to wall. At this point it had 100K miles and it happened more often, more readily. I pulled the injectors and used 1000 grit paper to polish every injector spool valve. I could not tell due to oil staining which were the replaced injectors (I could tell when they were dismantled due to new style magnets with occlusion reliefs) and the injectors were moved on a head gasket/stud job and not kept in order. That has fixed it for dozens of thousands of miles. There was a spool valve hanging under highest HP oil pressure and when the oil was over 210F temp. SO to cut to the chase: I think the 4 others being replaced will fix it if the stutter is actually a misfire like a gasoline engine with a bad plug. It sounds like that is what you are describing.
 

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Discussion Starter #10
I have a 2004 F450 that had loaded misfire f or a long time and many repairs and trips to dealer. For a long time I pursued tire balance and some other issues as the problem sort of felt like road or tire issues. Only happened when towing and under a load--accelerating with no downshift or pulling a hill.
Three injectors were replaced at to times by dealer under warranty with no change.
Anyway, I decided it was a misfire as driving in a few places where there was a wall I could hear it in exhaust with window open under pull next to wall. At this point it had 100K miles and it happened more often, more readily. I pulled the injectors and used 1000 grit paper to polish every injector spool valve. I could not tell due to oil staining which were the replaced injectors (I could tell when they were dismantled due to new style magnets with occlusion reliefs) and the injectors were moved on a head gasket/stud job and not kept in order. That has fixed it for dozens of thousands of miles. There was a spool valve hanging under highest HP oil pressure and when the oil was over 210F temp. SO to cut to the chase: I think the 4 others being replaced will fix it if the stutter is actually a misfire like a gasoline engine with a bad plug. It sounds like that is what you are describing.

Thanks for your input Jimmy


I really suspected injectors also, because everyone on this forum appears to have injector issues on high mileage engines, and four of mine have ~250K on them (life expectancy of 160K). However, I do believe I have to track down the GP#3 issue and verify the voltage stability issue is not a problem before I go to that level of work.



To that end, and as a result of Mark's input I've checked the belt on ALT #2 and it looks good, I've checked the wiring around the GP Control Module and it looks clean, I'm not suspecting the batteries, as they always have more than 11.5v on start-up (Scangauge II) and I keep a battery tender on it when not driving for awhile. I do have a bypass cable directly from my Alt #1 to the Battery and don't know how this could affect circuitry. I plan to do the GP diagnosis at the GPCM connector (per Dieseltech Ron's video) to verify GP #3 shorted/opened. And then would like to know which signals I should do data logging on while driving to further diagnose voltage drops.



Mark, are you talking about a 12V drop or a Ref Volt Drop?
Which signals would you recommend I track while driving?


So after I go winterize the Evaporative Coolers on the house (expect 20s tonight in Santa Fe) I'll get back to it...



Thanks again everyone for your help!!!
 

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Thanks for your input Jimmy


I really suspected injectors also, because everyone on this forum appears to have injector issues on high mileage engines, and four of mine have ~250K on them (life expectancy of 160K). However, I do believe I have to track down the GP#3 issue and verify the voltage stability issue is not a problem before I go to that level of work.



To that end, and as a result of Mark's input I've checked the belt on ALT #2 and it looks good, I've checked the wiring around the GP Control Module and it looks clean, I'm not suspecting the batteries, as they always have more than 11.5v on start-up (Scangauge II) and I keep a battery tender on it when not driving for awhile. I do have a bypass cable directly from my Alt #1 to the Battery and don't know how this could affect circuitry. I plan to do the GP diagnosis at the GPCM connector (per Dieseltech Ron's video) to verify GP #3 shorted/opened. And then would like to know which signals I should do data logging on while driving to further diagnose voltage drops.



Mark, are you talking about a 12V drop or a Ref Volt Drop?
Which signals would you recommend I track while driving?


So after I go winterize the Evaporative Coolers on the house (expect 20s tonight in Santa Fe) I'll get back to it...



Thanks again everyone for your help!!!
I was talking about the system voltage. If your voltage is staying above 11.5 volts when cranking then that is VERY good.
 

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Discussion Starter #12 (Edited)
Hey Mark,

When I said 11.5V when cranking, I meant while the GPs were on for the first 45 secs. after starting....

Also,
Originally I had asked a very difficult question about diagnosing the injectors. After that I started looking at DieseltechRon on Youtube and found his video on diagnosing misfires. (33.5 minutes of some fantastic information). I learned from the video that my power balance test in my Autoenginuity program is broken and the screen isn't refreshing at all! So, therein might be the reason I can't see any issues when I run it.


I did verify that Glow Plug # 3 is open by checking the resistance on each of the GPs on the odd side of the engine. I got a full open on #3 while all the others had ~ .5 ohms through them.


Thanks!
 

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Discussion Starter #13
Still Acting Up

:frown2: Put the new glow plug in today and checked the Turbo CACs for cracks or leaks. The clamps on all of the connectors needed to be tightened...
I plugged in the Autoenginuity and turned off all of the Antivirus stuff on the computer. The Power Balance test ran just fine and I couldn't see any of the injectors showing weaknesses. The delta RPMs for each cylinder were minuscule. I tried reving the engine and checking the balance but the test went wacko. So I commanded a 1500 RPM and ran the Power Balance Test with the same result. No issues.



So I took it on the road and duplicated the problem, and it seems worse than it was. I looked at the FICM Voltage and the Supply Voltage, and they were all where they should have been (FICM ~ 48v). I piddled around with the data graph and picked on the CKP & CMP in Sync graph. That thing was all over the place 1 and 0 never really staying in sync. Don't know if this is some kind of indicator.


I looked at the engine torque graph as I drove, and it was smooth in it's transitions.



The boost looked good as I accelerated and pulled up the hills, but the jerking was there anytime I had a ~1750 RPM loaded engine. I mean it really jerks!


Anyone got any thoughts or recommendations for my next step in diagnosis?


Thanks!
 

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/forums/images/TheDieselStop_2015/smilies/tango_face_sad.png Put the new glow plug in today and checked the Turbo CACs for cracks or leaks. The clamps on all of the connectors needed to be tightened...
I plugged in the Autoenginuity and turned off all of the Antivirus stuff on the computer. The Power Balance test ran just fine and I couldn't see any of the injectors showing weaknesses. The delta RPMs for each cylinder were minuscule. I tried reving the engine and checking the balance but the test went wacko. So I commanded a 1500 RPM and ran the Power Balance Test with the same result. No issues.



So I took it on the road and duplicated the problem, and it seems worse than it was. I looked at the FICM Voltage and the Supply Voltage, and they were all where they should have been (FICM ~ 48v). I piddled around with the data graph and picked on the CKP & CMP in Sync graph. That thing was all over the place 1 and 0 never really staying in sync. Don't know if this is some kind of indicator.


I looked at the engine torque graph as I drove, and it was smooth in it's transitions.



The boost looked good as I accelerated and pulled up the hills, but the jerking was there anytime I had a ~1750 RPM loaded engine. I mean it really jerks!


Anyone got any thoughts or recommendations for my next step in diagnosis?


Thanks!
That sounds like what I went through when my injector was acting up... but you said that your injectors all checked out, so I don't know what to tell you...

The FICM can have good values and still be bad on the logic side.
 

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Discussion Starter #15
A bit Stumped

:brickwall:
I have a 2004 F450 that had loaded misfire f or a long time and many repairs and trips to dealer. For a long time I pursued tire balance and some other issues as the problem sort of felt like road or tire issues. Only happened when towing and under a load--accelerating with no downshift or pulling a hill.
Three injectors were replaced at to times by dealer under warranty with no change.
Anyway, I decided it was a misfire as driving in a few places where there was a wall I could hear it in exhaust with window open under pull next to wall. At this point it had 100K miles and it happened more often, more readily. I pulled the injectors and used 1000 grit paper to polish every injector spool valve. I could not tell due to oil staining which were the replaced injectors (I could tell when they were dismantled due to new style magnets with occlusion reliefs) and the injectors were moved on a head gasket/stud job and not kept in order. That has fixed it for dozens of thousands of miles. There was a spool valve hanging under highest HP oil pressure and when the oil was over 210F temp. SO to cut to the chase: I think the 4 others being replaced will fix it if the stutter is actually a misfire like a gasoline engine with a bad plug. It sounds like that is what you are describing.

Jimmy, I'm stumped with just pulling all of the injectors and trying to figure out which of the ones need to be replaced when the power balance test doesn't show them to be bad. Is the AE testing tool a piece of crap? I saw on DieseltechRon's youtube post where he used the Ford interface tool to command each spool valve to move one at a time and was able to hear which one didn't move. The actual automated test showed the injector to be good, but when he did that individual spool valve command it showed which injector was obviously bad. I suspect your issue wouldn't have showed up with a cold, not running engine, and the test he did wouldn't have worked. I don't think AE will let me do that as it only allows me to turn off one injector at a time while the engine is running. Even pulling injectors and having them flow tested wouldn't find the issue you described with your injectors.


Dillon, I had FICMRepair fix my FICM when I originally killed it from low batteries so I don't suspect it.



Looking at all of the posts about CKP/CMP sync, it appears that the AE tool just allows me to look at the cycle of sync/unsync while it is running as nobody seems to think that this is an issue. I assume the CPK/CMP Sync is only an issue when you are trying to start it not after it is running.



I checked all of the wire chaffing points when I put the Head Gaskets in and didn't find anything. Of course that was 65K miles ago.


Tomorrow I'll go see if there are any codes beyond the overhead panel codes, and drive it while watching Vref to see if it's stable.
 

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Discussion Starter #16 (Edited)
Update from today:

Drove up and down the highway and had strong jerking going on in high gear. Looked at the Reference Voltage and Both FICM Main and FICM Supply. The FICM Main power fluctuated over 5 V (48 to 48.5). Reference Voltage stuck at 5Volts with no fluctuations.

Got back into the garage and ran Power Balance test, KOER Performance Tests, and pulled DTCs.
I also ran the "Bubble Test" and saw no bubbles being blown back into the secondary fuel filter bowl.

See Attached Screen Captures for each.

Assume the EBP out of range is because I have a CAT Delete pipe on the truck. Any other thoughts on what it could be?

Thanks!
 

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If your 04 has the ICP behind the turbo, then it is an 03 motor and it doesn't use the EBP sensor.

If it is going in and out of sync with a consistent rpm signal, then it could be an issue w/ the cam shaft sensor.
 

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Discussion Starter #18 (Edited)
Mark,

I just finished putting everything away and came in here to find your post.

My truck is a late 04 build with the ICP Sensor on the Rocker cover. So.... I guess it uses the EBP sensor, but I had believed in my head that it didn't for some reason. Sounds like others have had jerking due to Plugged/Compromised EBP signals... I'll clean it tomorrow and inspect the wires around it. I haven't messed with that sensor since I put HGs on many miles back! Wow! I hope, I hope, I hope......

The CMP/CKP sync rythmically pulses 1&0 sitting at idle (I tried to determine if this was normal by searching the forum and several seem to think so).

Thanks for your help!
 

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Discussion Starter #19 (Edited)
EBP Sensor Cleaning Didn't Help

If your 04 has the ICP behind the turbo, then it is an 03 motor and it doesn't use the EBP sensor.

If it is going in and out of sync with a consistent rpm signal, then it could be an issue w/ the cam shaft sensor.

Pulled everything out of the way to get to the EBP Sensor so that I could check wiring and clean it. Took it off and sprayed it with Electronic Parts Cleaner in the bottom of the sensor. Got the brake cleaner and a piece of weed wacker line and cleaned out the tube through to the manifold. Put all the CAC connectors back on and torqued them to 108in/lbs. Started it up and monitored EBP Absolute at idle and I can't remember what it was but it was either 11psi or 15psi. When I drove it watching the EBP it varied with engine speed and seemed to be working just fine. The truck still jerks when in high gear while trying to accelerate. Do you think I should go get a graph of RPM vs EBP? Edit - The EBP isn't out of range as I had earlier posted here, it's the EGR that is out of range (duh).


Then I pulled into the garage and set up the computer to track several CMP/CKP factors. Attached are the results of my diagnostics.


I would appreciate your thoughts on Next Steps....

Thanks!
 

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Looks like a camshaft sensor failure to me.

Edit - I forgot you have the later 04.

Yes, it would be good to see the graph of rpm vs EBP (and verify it at KOEO).
 

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