Warning long read, thanks for any input

Those of you that know I may be the highest mile-er truck on the forum. She runs great when she runs correctly so here is my current symptoms for this week.

1. Vibration in drivetrain not related to engine
My procedure to diagnose.....Downhill travel in nuetral, vibration got worse. Apply engine load and it lessons.

My theory---Replace all driveline bearings (ujoints) and differential check.
Ruled out another flywheel and blown rearend because both are new and the flywheel would be noticed in nuetral with revs. Diff I just reserviced a few months ago with no metal or noticed wear.

2. Engine surge
Symptoms. Engine runs as if it is constipated. While on cruise, all the sudden something just lets loose and she will lay you back in your seat at 80mph easy then back to constipated. Talking to good ol dad, we came up with fuel issues. New filter, no change. I run dual filter system with the spin on big truck filter the primary. Bowl is clean. New oil pump installed and instant oil pressure on guage. I run a 12 qt additional bypass filter system so my truck holds nearly 7 gallons of oil. Now I watch my fuel meter on my banks 6 gun and here is the following observation. On setting 5 the max fuel delivery I have is 142 percent at hard accelleration. Cruising I feel the surge and watch the guage at 110 percent and surge to 126. That tell me this is fuel related. I also observe the boost guage and I used to be able to get up to 26 easy with acceleration and loads. Im getting up to 21 and that is hard...no fuel, no expanded gas therefore no boost. Now occasionally it runs ok. I have surge even without Banks turned on.
Simple solution to clean the ipr again? or is there more to check. And no I dont pull codes, I have the aih disconnected, the backpressure disconnected, the kwik filter and the wastegate disconnected so those are not the issues.

Truck has 496,589k and still going

 

I think your on the right track w/ u-joints, sorry I can't help w/ the surge.

 

Come on now we have got to cross half a million.

I would like to see the mechanical pressure reading from the oil rail when this surge happens. I wish you had AE looking at ICP and IPR Duty cycle would really help.

Possibilities: (Off the top of my head)
ICP - could be an early sign of a biased ICP sensor, need to compare icp reading to actuall rail pressure.
IPR - generally when you have problems here they are to the sluggish side not sitting you back in your seat. When they fail they close.
IPR Tin Nut - Outside chance but make sure it is tight, when i did my drain valve i must of knocked it around cause i was having a little surging and tightening the nut cured it. With it loose IPR Duty Cycle was jumping around with no rhyme or reason.

Does it do it with cruise control on? (If no could be a pedal issue starting)

Attached is the voltage table for the ICP so you can compare to the mechanical readings

 

I will throw my fuel hat into this ring. I would suspect the fuel pump is on the way south.

 

After reading it again i am thinking the same thing. Or a severe Fuel Airation problem.

At first i was reading it as driving along normal and getting sat back in you seat. I missed the constipated part.

 

Nope not fuel pump, its new. Not fuel ariation because it will happen while I pull from top fuel tank and fuel return dumps in bottom tank. It will happen most noticed under cruise control and also the manual pedal. My system pulls the fuel reading directly from the fuel sensor ICP. I need some spects on making a fuel meter. I can get the guage marrow , its the info on the fittings and sizes to get. Any help would be great. How does the system determine defueling issues?

 

Well, new pump might have electrical or obstruction problem somewhere. That is what it sounds like to me if I was guessing, and I am. Since you do not think that is the problem, may be time to look at the throttle pedal assembly or the items AMiller posted earlier. I still say it is a fuel supply issue and that includes the system that drives the injectors.

Also, you have a complex fuel tank system, might you have a cap vent problem or something like that?

 

OK if Your "Fuel" reading is surging from 110% to 126% with no pedal input change Check the IPR closely.

ICP is reading the Oil Pressure in the driverside rail and Banks is interpretting it as a fuel delivery reading i guess. If the ICP pressure is increasing without the IPR being told by the PCM to increase duty cycle (pedal input, speed drop in cruise, ect) then something is causing the IPR to open and provide more pressure thus providing more fuel and the surge.

 

Here is a WAG i had while falling asleep last night Kennedy. Once you get that fuel pressure gauge hooked up see if the actual fuel pressure (not ICP) is fluctuating when this happens. The little spring in the FPR could be getting tired.

 

Hmmm, today I will start by cleaning the ipr again. I already know the nut is tight so that isnt the it. I may put a shim back in against the spring on the fpr but I have no clue on the fitting sizes to place a fuel meter in there. I dont like taking it apart and making multiple trips to the hardware store if you know what I mean. Thanks Alan, how is the new web site coming?

 

1/8" NPT thread size.
I don't have anything to add to the excellent information that Alan is providing so I'll monitor and say something if it hasn't already been said.
Sounds like your driveline is giving you the shakes to me as well.

 

Thanks Kwik. The closest I got to your location a few weeks ago was Spokane. Didnt even get to go see Fabman(Don) from the bio forum. Ill buy those filters someday