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@jstihl I checked the "A" and "I" voltages with the pigtail connected (backprobing) and disconnected per the chart below:
My "I" circuit is not greater than 12V at the disconnected pigtail per pinpoint test AB4, and my "I" circuit KOEO and KOER voltages with the pigtail connected are not in the normal ranges, yet the alternator is charging, based on monitoring the voltage at the battery.
With both alternators connected, and after starting the truck, the voltage sits at about 11.7V on my P3 brake controller meter, while the glow plugs are on. When the GPR opens up, the voltage quickly climbs to 14.4V over 2-3 seconds (both alternators putting out maybe a combined 100A at idle)
With the upper alternator pigtail disconnected, and after starting the truck, the voltage also sits at 11.7V, glow plugs on. After the GPR opens, the voltage slowly climbs to 14.4V over 30 seconds or so (just the lower alternator putting out, at engine idle, so maybe 50A, or less since it has a larger pulley than the upper).
It would be good to know how many others measure 11V at KOEO on the pigtail "I" circuit LTGRN/RED wire, upper alt (YEL wire, lower alt) when disconnected. Either our PCMs have an issue, or the pinpoint test value is incorrect.
A a lot of good information here thank you bwst! it seems that your p1105 code is coming from your voltage being less than 12 on the i circuit koeo. We both have the code but we both have charging alternators. Hmmmmm. I doubt the pinout test is wrong. We have voltage just not enough of it, got to be a bad ground right? Do you have the PCM ground strap on your lower 8 mm bolt? Thinking of trying that makeshift ground strap from the corner of the PCM to the underdash frame and see what happens.
It is a possibility that the pinpoint test is inaccurate. FTN and I identified an issue with the PCM pinout in the FSM. I cannot remember the details if it was for all of the PCM's or just the 2000 MY. I have not identified any other issues or misinformation in the FSM, but it is entirely possible. This is why Technical Orders and manuals have revisions and updates. Back in the day in my previous life we had a shop dedicated to keeping TO's updated with relevant information as the updates came out.
It is entirely possible that the FSM from 2007 and being "Service Information" and "Training Information" is not 100% correct. In my mind it is 100% better than nothing, but it might not be 100% correct.
jstihl, I didn't compare your readings side by side with what Jeff posted, but from my memory they are pretty close right?
If you are focusing on grounds, the grounds are detailed in the FSM. There are a lot of them, but which ones specifically tie into the PCM or charging circuits may take a bit of time to identify physically and within the FSM. I can attempt to help with that if you feel that is the direction you are going, just let me know.
I am really hoping for a resolution for you soon jstihl, which may lead to a resolution for BWST.
Well I pulled the pcm again, cleaned the contacts, checked all four PCM grounds for continuity and everything checked out. I also ran a ground strap from the PCM case to the underdash frame. After that I checked my i circuit going to the alternator and it was at 12.2 volts. Just as soon as I got excited and thought I fixed the low voltage on the i circuit, the voltage started dropping and went down to 11.7 🙄. I had just started the truck and I guess it was residual power.
The idle started surging up and down again today so I put in a new icp sensor from diesel o rings and unfortunately there was no difference. Maybe it's the IPR? I know in a lot of these surging cases the IPR is the culprit. Just hate throwing away money on parts that I don't need being that I just changed the ipr earlier this year. Not really sure where to go from here....
Can you post a pic of how you did the ground strap for the PCM? I may need to do that. At least your I circuit is much closer to the stated normal range. I wonder if your p1106 will stay away once you clear it now.
Darn that surge to heck! You're right, the IPR is often the reason for an unsteady idle. You're current one is not that old though, and they are a pricey part.
Have you performed the KOER On Demand self test with Forscan? It will exercise the high pressure oil system a bit.
From FORScan:
Key On Engine Running On-Demand Self Test Description Key On Engine Running (KOER) On-Demand Self Test is a functional test of the powertrain control system performed on demand with the engine running and vehicle stopped. The PCM performs injection control pressure (ICP) and exhaust back pressure (EBP) system function check during this test. DTCs will be displayed.
Another thing that might be helpful to see is a log of your truck making a WOT run or two, with all of the parameters we typically monitor included. Just trying to get more data to justify a sensor purchase, or maybe something will reveal itself during this stress test.
Maybe it's the IPR? I know in a lot of these surging cases the IPR is the culprit. Just hate throwing away money on parts that I don't need being that I just changed the ipr earlier this year. Not really sure where to go from here....
if your current IPR is Motorcraft, they have a two year warranty. I bought a new ICP and sent my 18 month old one back to Riffraff. Ford approved the return and Clay refunded the money I spent on the old one.
Did you save the old IPR? Have you ever tried tearing one down and cleaning? It's pretty simple, but not sure I'd recommend it if you plan to attempt a return. You could try it with the old one if you still have it.
Can you post a pic of how you did the ground strap for the PCM? I may need to do that. At least your I circuit is much closer to the stated normal range. I wonder if your p1106 will stay away once you clear it now.
Darn that surge to heck! You're right, the IPR is often the reason for an unsteady idle. You're current one is not that old though, and they are a pricy part.
Have you performed the KOER On Demand self test with Forscan? It will exercise the high pressure oil system a bit.
From FORScan:
Key On Engine Running On-Demand Self Test Description Key On Engine Running (KOER) On-Demand Self Test is a functional test of the powertrain control system performed on demand with the engine running and vehicle stopped. The PCM performs injection control pressure (ICP) and exhaust back pressure (EBP) system function check during this test. DTCs will be displayed.
Another thing that might be helpful to see is a log of your truck making a WOT run or two, with all of the parameters we typically monitor included. Just trying to get more data to justify a sensor purchase, or maybe something will reveal itself during this stress test.
Darn it I forgot to take a pic of the ground strap. It's super easy though, just pull the pcm and release the pcm from the plastic case. then just crimp on an eyelet terminal to a peice of wire, remove the top back bolt( if you picture th pcm as it's installed it will be the bolt that is furthest from the firewall and on the top of the pcm) , then screw the bolt down through the terminal. Assuming you have a hole cut out of the plastic case for the PCM so you can remove your chip or Hydra, you can just run the wire out of that hole and up to the under dash frame . if you remove the kick plate under the steering wheel to access the fuse box you will see a couple bolts to the right of the fuse box that other wires are grounded on. Just crimp on another eyelet terminal at the end of your wire and screw it onto the frame. I can find the thread where I got the idea from, Wes444 has a pic on there.
Can you run the KOER test with the forscan lite app? That would be great to see what a WOT log looks like, I have always wondered how my truck would compare and to see if anything is off.
Did you save the old IPR? Have you ever tried tearing one down and cleaning? It's pretty simple, but not sure I'd recommend it if you plan to attempt a return. You could try it with the old one if you still have it.
I think I may have saved it now that you mention it. I will do some searching in the old 7.3 box
if your current IPR is Motorcraft, they have a two year warranty. I bought a new ICP and sent my 18 month old one back to Riffraff. Ford approved the return and Clay refunded the money I spent on the old one.
My issue was the IPR.
Thank you for the heads up on the warranty, I will definitely look into that
As for an IPR, I don't trust anyone but Clay at Riffraff or Bob at Diesel O Rings for decent prices and genuine parts. You can get them from dealers like Ford or International, but they are going to cost you.
I have charted the data log you sent me, it is attached.
VPWR and TC_SLIPACT lay right over each other, so I briefly removed TC_SLIPACT in order to see the VPWR line since you were delving into the charging system recently, it was smooth. Looking at the PID CSV tab, VPWR is stead at 14.25 the entire time.
Via email, jstihl told me the following concerning this data log:
Originally Posted by jstihl via email
RPM's were going up and down from 703 - 760, IPR duty cycle was going up and down also.
Looking at the RPM trace line in the top graph, it looks fairly steady. Looking at RPM in the PID CSV tab, you can see where it gets as low as 704 at line 226 and then it hovers between 715 and 745 most of the rest of the time. I believe jstihl has told us in the past he had his tuner raise the RPM to 760 for idle, but I am not sure if I am remembering that correctly.
Looking at the ICP trace line in the top graph, you can see it waiver a bit. The ICP jstihl has in the truck is brand new within the past 2 weeks and is Motorcraft.
IPR DC% stays in the high 11 to low 13 range for the most part throughout the data log.
duck fan told us recently:
As far as the IPR being steady while the ICP fluctuates, keep in mind that all the PCM sees is what the IPR is commanded to do. Just because it is calling for a steady state % does not mean that it is delivering it. The IPR is the only thing that makes "sense" at this point. That doesn't mean that it is for sure the problem.
Looking at the FUELPW trace line in the second graph, you can see the same sort of wavering from this PID. jstihl recently said he might have a second IPR he can break down and clean up in order to try. I think this might be a good idea since it is only time involved and no financial loss. We saw similar symptoms from the ArmyLifer surge condition a couple of weeks ago and a new Motorcraft IPR fixed his issues. That is not to say that jstihl is having an IPR issue, but I don't know what else to suggest based on the chart trace lines.
I have not pasted any images of the chart because they are mostly straight lines unless you are using the mouse to pinpoint a specific spot or looking at the PID CSV tab which has the data log on it. Sorry this was not more conclusive jstihl...
Thank you for your feedback Sous. The truck was definitely fluctuating quite a bit, I could hear it and feel it. I was not able to open the tab that you posted to look for high and low numbers but I was pretty sure I saw it go up to the high 750's and as low as 708, it all happens so fast I was just trying to go off of memory. After I log the information I'll play it back very slowly to look for high and low numbers but I did not do that with this one since I thought for sure it would show fluctuation on the chart. Comparing this truck with a good running truck on a chart may look the same but I promise there is something going on. Comparing this f350 to my f450 , just watching the numbers there is quite a large difference. My ipr duty cycle on my f450 does not fluctuate at all at idle , and the icp and rpms stay grouped together much better . In the log I sent last the ipr duty cycle was going up and down quite a bit , I have never seen a good running truck fluctuate like that, it usually stays the same at idle. Perhaps the charts are better suited for more drastic fluctuations like armylifer had is all I can think of. If the charts were more "zoomed in" or enlarged I'm sure the fluctuations would be noticeable. Just something to keep in mind for the next guy that has fluctuations like mine. rpms are supposed to be at 730 on my truck so maybe it is so noticeable because of how quickly the RPMs drop or go up, I don't know. It will hover around 730 for a little bit and then all of a sudden drop and then go back up to a high point and then it will start hovering again. I will try cleaning out my old IPR and installing that to see what happens. As far as vpwr pid goes it has been staying steady, before I cleaned and reassembled the pcm and alternator wires the voltage would stay around 12.6 for a couple of minutes at start up and then all of a sudden spike up to 14.4. Now it slowly climbs to 14.25 and stays there. Thank you guys for following along and I will report back with any new information
