IDM has good ground and alternator voltage when running.

I can accelerate without the stutter,If i press the skinny pedal very linear.
To 100 mph,2.5 Bar of boost and 1100f EGT.

With heavily fueled DIY tune.

Sudden demand of fuel makes it stutter.

 

In my experience, low fuel pressure from pump that can’t keep up with demand just causes loss of power. Kick on 2nd pump and it feels like the ‘go baby go’ button.

I’m wondering if something about you fuel system is causing cavitation/air intrusion. AIR can totally cause a stutter and affect ICP.

If you haven’t done the in-tank mods yet, I strongly recommend it. Deleting the recirculation chamber and adding a serviceable pre-pump filter that can handle the volume you need (RACOR PS120) can’t hurt.

https://www.ford-trucks.com/forums/1...poon-mods.html

 

No in-tank mods yet done.

I've read only one thread where CPS was too far from cam gear.
Timing was messed up becouse of that.

CPS was brought closer (machining from front cover?) and problem was solved.

Far streched but plausible to me,i will measure the distance from cam gear to front cover outer surface.

Don't remember for sure was all that discribed after front cover change or cam walk..

Does "cam walk" happen in or out?

Early years 7.3 had something with front cover machining tolerances and CPS sensor was offered with shims.

Remember,i have changed my front cover.
Has HPOP reservoir filter in it.(99-03 applicable)

 

Yes, I remember that to. The after market, I believe wasn't machined to let the CPS down far enough and it had to be modified. I was still thinking push rods because you said there was two different sizes. And lifter maybe pumping up at higher RPM's and there the miss. CPS seems more likely though. I hope you get this figured out soon. God bless,

 

Another far streched theory:

Chinese Melling copy LPOP not providing enough pressure for the lifters,under sudden load..??

 

There is no good reason not to do this. It’s easier than the other things you are considering and all of these trucks need it by now.

 

I agree except for one potential item. He lives in extreme cold weather. The recirculation chamber allows some use of the heated return line fuel and may help prevent gelling. Along with the potential of the small filters we use gelling up themselves due to the elements (I’ve seen at least 1 post about it happening).

Just something to consider with his particular circumstances.

 

I think this idea that recirculating fuel (or fuel bowl heater) mitigates gelling is a myth.

If fuel is going to ‘gel’, it would do it in an exposed, steel 3/8 or 5/16” diameter fuel line, not in a tank or a filter with any volume of fuel. It will also happen upstream of the fuel pump, because this style pump pushes fuel way better than it ‘sucks’ fuel. The engine is COLD at start up, so it’s not helping thaw any gelled lines - especially between tank and pump where the problem is. Even if engine was warm, the duckbill on the recirculating chamber will allow returned fuel to dump into the tank of the suction line is gelled. It cannot ‘push through’ and un-gell the problem area.

I had a Vegistroke customer call me one COLD NJ morning to sing the praises of his then new VO conversion. His truck was parked overnight with the block heater plugged in and he got up before dawn to go plow snow. Truck fired right up and he backed out of the driveway onto the city streets. About a block later, truck isn’t running good and he realizes his fuel pressure is zilch. With no place to pull over, he thought WTH and flipped the switch for the VO pump. Fuel pressure shot up and truck started running good!! He went on to plow snow the rest of the day. But, the diesel remained ‘gelled’ until he put the truck in the warm shop for a couple hours. The truck ran on VO because all of the fuel lines before the pump are heated with coolant.

 

aka How To Set Your Truck On Fire.

 

I'm going to agree with SkySki. If your truck is sitting outside at -35 and the fuel is already gelled...you are screwed. If it's maybe -10 and you get it started, you might find there is just enough fuel flow for it to idle and if you let it idle for long enough you might think "Hey, this is gonna be alright." Until you get going down the road and the -10 air is cooling the hard line running down the frame rail.

Gelling is more a function of improperly treated fuel from the terminal than anything.

 

wonder if the fuel regulator is causing it
slow on pedal is ok
stomp not ok

I had a flakey faucets in my house, turn slow and flow was fine. Turn on fast and it would shudder out of the faucet and shake all the pipes. This went on for a while until the meter was replaced and no more shudder since.

have you done a fuel flow test and measure its GPH?

 

I haven't done fuel flow test.

I asked in the very early stage that can our fuel pump fail to provide proper flow even If pressure is steady.
I have stock Bosch pump.

I see no fluctuating or drastic dropping in fuel pressure.
Slight dipping under heavier demand,maybe 5psi.

My electrical pressure gauge is in the valley,after the regulator.

 

It is possible to maintain pressure with air in the fuel.

Allowing return from FPR to dump into a bucket should rule this out.

 

Lots of going on currently.

Friends(closer friend with my brother) house burned to the ground in thursday.

Along with multiple cars and even excavator caught in the fire.

Cats died in.
Dog was rescued.

No human casulties/ injuries.
Mentally and financially catastrophic,of course.

It's was a old village school made from timber.

 

We hate to hear that....

Prayers for those affected by the tragedy.