I would think pressure is low but the duty cycle to is fairly low for wot....why?

 

Never asked but maybe it was in the driveway and not on the road under load? If so then it might be about right.

Another test you can try is at idle and in park is to go to WOT and watch the tac. It should go smoothly up to red-line however I would stop around 3000 RPM. If you get a stumble around 2000 RPM or so then an HP oil leak might be an issue. We all like to get low millage OBS trucks as they are desirable. However the issue is the age of our rigs are quite old and that low millage means it has not been driven much and seals tend to age, such as injector oil rings. Just a thought ...

Let us know what you find on additional testing ...

 

Not sure what all you checked. I had a similar issue.. Decent acceleration on 1/4 throttle and under wide open I lost power.. Found out, that I lost fuel pressure under wot due to a partial clogged pick up tube. The coating inside the tank is separating and floating in the tank..

 

I measured fuel pressure WOT and had it bouncing from 30-60 until about 3k rpm then it leveled out to about 5500. What measurements did you have? And what was your solution?

No all measurements were taken driving on the road

I will measure throttle position in the am I've brought it to 3k parked with no stumble very smooth increase.

I plan to perform FPR mod and clean strainer as well so we will see in the am

 

I had pressure at 65 and while under load it dropped to 30. I ended up dropping the tank , blew out the lines and made a strainer for the pickup tube . I will replace my tank soon though

 

How did you come to that conclusion?

 

It started to get worse with the power loss, sometimes cleared up when switched to the other tank, so it had to be fuel related.

 

I would agree with Jim that ICP is quite low at WOT under load. At a duty cycle of 35%, my truck (with auto trans and stock everything else) gets up to 2500-3000 psi ICP.

Easiest thing to do is change the oil if you don't know how old it is (or that the PO put the right grade in). ...you said the truck is new to you, right? also, look closely at all the HPOP plugs and fittings in the heads - in the same position as the ICP over every other cylinder. I had a bad o-ring under one plug one time that was limiting my high end ICP values.

TPS could make sense, but from what I've seen, IPR Duty Cylce is tied pretty closely to throttle position. I only get about 30% DC when my foot is smashed to the floor, so it sounds like your PCM knows you want to go fast - just can't make it happen.

 

I didn't have much of a chance to look at everything i wanted to as one of my guys didn't show up for work this morning But I did check the TPS and there are no dead spots.

I will be changing the oil with motorcraft 15w-30 diesel tonight with motorcraft filter, fuel filter, and FPR mod and cleaning

Oldwoodsdiesel, You say to check the fitting to be in the same postion, can you elaborate on this a little more. Visually everything looks correct without removing
anything. There are absolutely no oil leaks and the whole plenum is dry so they arent leaking oil or should I be looking at something different or actually removing the sensors and inspecting? Thank you.

 

Yep, still could be fuel pressure so do the bb mod. Kind of hard to measure it under load while driving. If that fixes it then you are going to want to replace the fuel pump eventually or go electric fuel.

 

Ok I disconnected the icp and drove and still same boost levels except now the trans was shifting very hard so I reconnected it and cleared faults. No change in engine performance though

 

JM - sorry for the delay - the plugs I was referring to are in the heads pointing toward the center of the engine valley. the ICP is in the first position on the driver's side head, there's a plug in the second one (I believe), the hose from the HPOP is in the third one, and there's a plug in the 4th one (all on the driver's side.) on the passenger side, there's 3 plugs, with the hose from the HPOP going into the 2nd cylinder position (from the front of the engine). the plugs are all hex head straight thread, 0-ring'ed plugs. look at all of them with the engine running and make sure there is not oil seeping out from under the plug head. it'll be a slow leak, but noticeable. if there is a leak (under one of the plugs or one of the hose/ICP fittings), you'll need a new o-ring for the offending fitting. (diesel o rings.com)

there are also two HP oil plugs on the rear of the heads. much bigger, but also o-ring'd. they can leak too, but are a much bigger pain to fix, so I hear.

any progress on your diagnosis? I have similar issues as you - i'm nearly convinced its a trans problem, but not 100% sure. its weird, though - in neutural, or P, I stop on the pedal and the RPMs go smoothly up to 3000+ and the engine sounds good. put it in gear and its like the engine doesn't know I want it to rev up to full throttle and the boost is low. and acceleration is terrible. kind of like the trans is slipping, but something is also 'governing' the engine, as i'd expect it to go full throttle if the trans were really slipping...

also - the o-ring problem I had was on my other truck, and didn't accompany anything like i'm currently experiencing on this truck...

 

OLDWOODS, I will check those fittings tonight thank you for the input. I have not made much progress on the diag as things have been a bit crazy lately.

I have however changed out the oil and filter with a new fuel filter all OEM ford parts Motorcraft with 15w-40 Motorcraft oil. I also performed the BB mod and cleaned the fuel bowl filter which was an atrocity full of sut. After completing all of this I have the same exact symptoms. Now the acceleration cold is how it was when it was at operating temp so it is better though its the same situation, I stomp on it and it slowly accelerates but if i just stay into it about half throttle or less she will go on smoothly. No smoke still.

What else could cause low ICP pressures like that?

 

low ICP pressures would be a leak somewhere, failing HPOP, or failing IPR. i'm pretty sure my issue is not high pressure oil related, though, as my pressure builds to ~2500psi at ~30% duty cycle, which is nominal, I believe.

i'll be swapping out my transmission for a manual trans in the coming weeks, though, so that'll answer the question of whether its transmission related...

if its still doing the same thing after, then i'm going to start checking out the fuel system more closely. I just bought an electronic fuel pressure sender to hook up to my Aeroforce scanguauge, so we'll see what it does there. if fuel winds up being the culprit, i'm just going to gut the whole system and go e-fuel.

interestingly, enough, my fuel bowl and regulator screen was also a sooty/black mess. I wiped the bowl and screen out real good, but it didn't seem to make a difference.

with my RPMs going up from idle to 3000 very smoothly and consistently in P or N, though, i'm thinking fuel is not the culprit, though - have you done this pretty easy test yet? any hiccups during the rev?

I also go no smoke out of my tailpipe, ever.

i'm kind of wondering about an intermittent IDM problem. like if IDM voltage were low, it would definitely bog down the whole engine, i'd guess. I suppose I could put an oscilloscope across the an injector during driving and check the waveform - but i'd have to find a portable scope I could borrow first. the last place I worked had one that would be perfect. nothing I can think of now, though...

 

Do you have AE? It measure Pulse Width which I reckon is what you are looking for.