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IPR duty cycle numbers and workings

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IPR duty cycle numbers and workings

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  #1  
Old 02-11-2018, 06:53 PM
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IPR duty cycle numbers and workings

I am still trying to get a good understanding of all things IPR, ICP, Expected ScanGauge 2 readings & IPR Duty Cycle. Any help/comments /info appreciated. Mostly IPR. I'm working with a 2003 E-350 7.3L . (NO Problems. Just wanting to learn more). I think I got confused after watching a VERY INFORMATIVE Diesel Tech. Ron video, (R.I.P. Brother), Where he explained the relationship between IPR & ICP numbers & how they could be used to diagnose some HPOP system problems. EXCEPT (as I later learned) he was demonstrating on a newer truck/engine like a 2004 6.0L engine and those have DIFFERENT IPR Duty Cycle numbers than older 7.3's do. ( he was talking about between 15 to 85% numbers). What I have recently and happily learned from Oregon Fuel Injection, Inc. Site is the 1999 to 2003 7.3L engines will see Scangauge II IPR Duty Cycle numbers between 09% to 40%. They show IPR numbers like.... IDLE = 9 - 11% Hard Acceleration = 35 - 40% (They also show a WOT in Neutral of between 18 - 21%). I don't know about THAT one because I would NEVER WOT my engine in Neutral! It sounds like it's going to blow up if I do that. Just doesn't seem to be a good idea. But that's just me. Anyway....Those numbers seem to be what I am seeing so now I know my SG II is working O.K. and I have the correct RDX MTH...codes programmed in. What I don't have a good understanding of is the term used (duty cycle) or why the numbers used or (programmed) into the PCM ... are between 09 and 40%. In my simplistic mind it should be between 0 to 100%. But I could understand if someone explained that the IPR can never be FULLY CLOSED or OPEN so it used numbers like they do to represent that say at IDLE it is 9% open (or closed) because if it were 0 or 100 the engine would not run because you have either completely blocked off the ability of the valve to (dump) or recycle oil through the HPOP... So I could understand that if it were explained. Or if it's just because that's the numbers the people that programmed the PCM choose to use for whatever reason. Also I would like info or explanation about (duty cycle). Or maybe better asked....What exactly is this IPR valve and what seems to be an electric controlled coil around it doing? Is it just sliding a piston that opens or closes some internal port (slowly) to control HPOP oil pressure to the Head Galleries? OR is this piston moving very fast (many times per second) to control the oil pressure. I guess I ask that because of the term (duty cycle) that's associated with it. They don't just call it % open or closed. Now I will also ask if the ICP sensor is located on the front of the drivers side head? As I have learned, that is something I will want to be able to easily locate to disconnect as part of diagnosing a no start condition. (it causes the PCM to default to a 725 p.s.i. reading from the ICP sensor, thus allowing the engine to start if it should be that you have a bad ICP sensor). So my basic question is about how and why the IPR works and the numbers and (term) used to describe it? Thanks for any input on the subject. DDT
 
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Old 02-11-2018, 07:02 PM
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Paragraphs, my friend, paragraphs.
 
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Old 02-11-2018, 07:54 PM
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The ICP voltage increases or decreases based on what the requirement for the engine load and what's desired. That is the whole function of the ICP. This is based on both Rotation Crank Value and Throttle Position.

The IPR regulates that pressure. The IPR is from 0-65%. 0 being closed and 65 being open all the way. The PCM sends the signal based on the ICP. The signal is Voltage sent to the Coil of the IPR, the more voltage the more open, the less voltage the less open. A Spring does the closing in the IPR.

So, the ICP is the Water Pressure, the IPR is the Nozzle on the Garden hose.

That's about the simplest way to explain it. It is, really, that simple.

ICP: 5 Volt Reference Circuit, 1.0 vdc @ 580 psig, and 3.22volts @ 2520 psig.

These are the table perimeters.

ICP Vdc
0 0.2
200 0.4
400 0.73
600 0.96
800 1.2
1000 1.4
1200 1.6
1400 1.9
1600 2.1
1800 2.3
2000 2.6
2200 2.8
2400 3.0
2600 3.3
2800 3.5
3000 3.8

This is the Duty Cycle - A Duty Cycle is a time per division of an electrical waveform, a "Signal" to or from the PCM. Also known as I/O on a Bus. In this instance, the cycle of operation of a the IPR operating intermittently rather than continuously.

IPR: Idle Warm: 8% - 14%, Idle Cold 10% - 15%, Electromagnetic Coil Test: OHMS = 10.2 - 10.6, Range: 0% - 65% (Not more than 20% Starting).

Now, my eyes hurt from reading your post. A carriage return occasionally would help.
 
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Old 02-11-2018, 08:16 PM
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Originally Posted by pirschwagon View Post

The IPR regulates that pressure. The IPR is from 0-65%. 0 being closed and 65 being open all the way. The PCM sends the signal based on the ICP. The signal is Voltage sent to the Coil of the IPR, the more voltage the more open, the less voltage the less open.
Not quite.

The voltage is a constant 12 volts to the IPR. The valve is controlled by a variable duty cycle carried on a 440Hz frequency on the ground side through the PCM.

Also, the higher the duty cycle (higher average current through the IPR coil), the more CLOSED the IPR valve is thus keeping the return from allowing higher flow back to the oil reservoir.
 
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Old 02-11-2018, 08:20 PM
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Originally Posted by cleatus12r View Post
Not quite.

The voltage is a constant 12 volts to the IPR. The valve is controlled by a variable duty cycle carried on a 440Hz frequency on the ground side through the PCM.

Also, the higher the duty cycle (higher average current through the IPR coil), the more CLOSED the IPR valve is thus keeping the return from allowing higher flow back to the oil reservoir.
You are right! (Good catch)
 
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Old 02-12-2018, 06:21 AM
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I apologize, I didn't read the whole thing. My old eyes kept getting lost in a sea of words, but I think I have the gist of the question (or at least I hope). You might want to click this [LINK]
 
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Old 02-12-2018, 09:40 AM
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Originally Posted by Tugly View Post
I apologize, I didn't read the whole thing. My old eyes kept getting lost in a sea of words, but I think I have the gist of the question (or at least I hope). You might want to click this [LINK]
Here's a question about the intensifier piston and injector...

If fuel pressure is 50 psi, and ICP is a given value (let's say 2000 psi for an example), it injects a certain volume of fuel at a certain pressure, right?

What happens if the fuel pressure is 100 psi and same 2000 psi for ICP?

Being DOUBLE the fuel pressure would seem to be significant, but only 50 psi is very small compared to the ICP oil pressures.

Liquid is not compressible, so there *shouldn't* be a volume difference per injection, right?

So the question: What effect, if any, does high fuel pressure have on the injection and running process?

(Other than premature Parker seal failures and maybe extra wear on the pump and bowl seals)
 
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Old 02-12-2018, 12:52 PM
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No effect at all. Think Windex spray bottle. Spraying doesn't directly use the fluid in the bottle, it uses what's in the tiny reservoir in the handle. Releasing the handle is the action that refills the tiny reservoir from the bottle.

The HEUI is very similar in this regard - the fuel pressure does nothing more than make sure the tiny reservoir in the injector is refilled before it is needed for the next injection event. Too high - premature wear and tear. Too low- reservoir fails to reload at high RPMs and/or fuel demand. 50 to 60 PSI - Goldilocks.
 
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Old 02-12-2018, 06:05 PM
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O.K. Thanks for the information. I am getting closer to having a better understanding of it all. I apologize for the lack of proper layout & format of the post. But it's always appreciated to have your faults pointed out.

Maybe some further information?
1st. I ask pirshwagon. And let me start by thanking you for the Table Voltages and IPR Coil Coil Test OHMS numbers. That's good info to have in the files.
Now, You say the IPR DC is from 0 to 65%. I get the 0% (as I imagine you must have a starting point when the engine and key is OFF. But the information I read on the Oregon Fuel Injection Site was for a 35 to 40% DC at "Hard Acceleration" (I generally interpret hard accel. as WOT.
You listed the Max. IPR DC as 65%. So is that possibly the "programed PCM limit", IE: If the HPOP or some other portion of the closed oil system is leaking or faulting, The PCM will (allow) the IPR DC to go to the Max. of 65% in an attempt to compensate for the leak/fault before it throws a DTC or otherwise somehow stops attempting to make a correction?

I ask because I have gone WOT/ Hard Acceleration, and I have only ever saw IIRC IPR Duty Cycles in the high 30's. 2nd.

To cleatus12r. Glad you made the technical correction/ catch about the electrical operation of the IPR. I cannot claim to be an electrical wizard so if you would indulge me for a moment might I try to put in in my own words and you can tell me if I am getting close to my understanding of this.

First I must admit to my lack of full understanding of the 440Hz carrier frequency. But I do understand BASIC electric current wave form and Hertz. (Mostly associated with a/c house current, IE 60Hz. IE: 60 times/cycles per second.) I guess I would say in MY words & understanding here (about the IPR) is that the amount of voltage allowed to (stimulate) the EMF of the coil is regulated NOT by a change in the supplied voltage (you say it's a constant 12 volts), But instead by the amount of resistance caused on the Return or Ground side line back to the PCM. Said resistance being the result of the Duty Cycle. And said DC being also controlled by the PCM which takes into consideration a few other factors like the TPS with ICP sensor readings to decide what is being called for. Are we talking a 440Hz return signal that is increased or decreased to control the strength of the EMF of the coil?

Also, if I understand what you wrote....The spring in the IPR is always trying to hold the piston/return OPEN, and the coil when getting MORE VOLTAGE (controlled by the DC on the IPR return line) is what pulls the piston to close OFF the oil return circuit in the HPOP, thus creating the Higher oil pressure in the oil galleries, thus the ICP sensor reads those higher pressures and based on constantly changing TPS , HP and I am sure other sensors that are signaling the PCM, There is a constantly changing DC percentage being sent to the IPR (RETURN LINE SIDE).

If I basically have this correct I still must admit a bit of curiosity of wanting to understand the 440Hz on the ground/return side. Does the 440Hz change? Or does that remain constant and some other signal (within) the 440 wave change? This sounds to me like understanding Radio wave carriers and signals? Am I close?

Hope I put enough indentations, spaces and paragraphs in this post. I didn't care about English Spelling or Grammar in HS and feel even with all the mistakes I make I can still get my point across in written word. Even if it's an embarrassment to the public education system.

Anyway,,,,I thank all of you for the time to read my way to long posts and detailed questions. I am SURE there are others that want to understand this stuff and might figure it out by reading all my (dumb ed down) questions. Thanks again guys.....I DO think I am getting a better understanding of how this all works in concert. But YOU tell me. DDT
 

Last edited by dieseldogtom; 02-12-2018 at 06:10 PM. Reason: remove emogies
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Old 02-12-2018, 06:13 PM
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Google "pulse width modulation". In the case of the engine in question, the frequency of 440Hz remains constant.
 
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Old 02-12-2018, 06:31 PM
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Originally Posted by dieseldogtom View Post
Now, You say the IPR DC is from 0 to 65%. I get the 0% (as I imagine you must have a starting point when the engine and key is OFF. But the information I read on the Oregon Fuel Injection Site was for a 35 to 40% DC at "Hard Acceleration" (I generally interpret hard accel. as WOT. You listed the Max. IPR DC as 65%. So is that possibly the "programed PCM limit", IE: If the HPOP or some other portion of the closed oil system is leaking or faulting, The PCM will (allow) the IPR DC to go to the Max. of 65% in an attempt to compensate for the leak/fault before it throws a DTC or otherwise somehow stops attempting to make a correction?
That 35%-40% you're reading is what they claimed as "averages" for a bone stock truck.

Stock calibration limits to around that 65% duty cycle.

Keep in mind what Cletus posted, this is a duty cycle, not a voltage or percentage of valve closed. Meaning 40% duty cycle doesn't actually translate to the valve being 40% closed. 65% duty cycle doesn't mean the valve is 65% closed.

Now it is possible with tuning to change that maximum duty cycle in the calibration to go all the way to 100%. The problem is that in almost every single scenario, nothing is gained. You don't get any additional oil pressure when that threshold is raised. So 65% duty cycle will be the same oil pressure in the same exact scenario as it would be at 95% duty cycle.

Which brings us to the next part....

Just because you aren't reaching 40% duty cycle or 65% duty cycle doesn't mean that you are losing oil pressure. In fact, it's the opposite. It means you are maintaining the pressure that the calibration is asking for during the injection event. If the PCM is asking for 2500 PSI, and one truck did it at 30% DC, and another did it at 40%, it doesn't matter.

If the HPOP was unable to keep up with the demand and oil pressure was dropping, the PCM would command a higher duty cycle to bring up the pressure. If the pressure still doesn't come up, the PCM will continue to demand a higher duty cycle until it reaches the limit set in the calibration of the PCM (factory 65%). If at the max commanded duty cycle the oil pressure still hasn't reached what is demanded, a code will be set and the check engine light illuminated. So if yours hits 2500 PSI at 30%, but your buddy is sitting at 2100 PSI at 65% and tripping the engine light, he's got an issue and yours is perfectly fine.

Hopefully that explains it without getting too technical and confusing for everyone.
 
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Old 02-12-2018, 07:06 PM
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Dieseldogtom,

First let me say you are asking some very good questions

As the guys are saying, the IPR%, ICP, and other items are all pieces of a moving puzzle, usually "seeking a target" of some sort. As tuners, these fellows are very familiar with that process, which some of us consider an art form as to how they attempt to define and meet those target values.

I would invite you to check out some of the graphing threads.

Although not written in stone, there are sections of performance- such as 45-85mph WOT- during which certain relations between sensor values play out and can be visualized, often leading to quick and fairly accurate assessments of "healthy performance" or shortcomings.

A screen snapshot, max or min values, or whatnot can be helpful are are only one datapoint and of limited (although potentially important) value.

I hope I explained that well enough

As for the grammar? Heck, we don't care.

But the formatting and blank lines? VERY important. As a group we use this site on computers, tablets, phones, maybe even tin cans and string, LOL!

We tend to skim a bit. We go back and forth to the information and any other reference material we believe would be helpful to contribute to the thread.

As such, it is easy to lose one's place in a long, run together paragraph. But feel very free to offend your English teacher's version of paragraphs. Often online/conversational style posts do NOT follow her rules,

I often break each change in thought, for sure, but I also try to break up data sets, separating important info/specs, and sometimes just when my pinky finger feels neglected, LOL.

So feel free to post whatever questions and discussions you like, but give us a "break" (paragraph) once in a while so we don't get lost along the way
 
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Old 02-13-2018, 12:34 AM
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Thanks everyone. I have a MUCH better understanding now of what was probably my biggest confusion. The term (Duty Cycle). And thanks for some of the links. They also had me reading other explanations of (Duty Cycle) . I'm pretty sure I now get that this is a situation that is related to computers and how they work vs. the old school way of controlling voltage with resisters or potentiometer's . I also see that I probably don't really need to know anything about what frequency the IPR/PCM signal is operating on. Just that Duty Cycle is the ON vs. OFF time % and that it is happening hundreds of times a second to (develop) a specific voltage on the coil of the IPR. I am aware that the duty cycle % is NOT a value of % open or closed of the actual valve or piston in the IPR. I am also pretty sure I understand the fact that lower duty cycle numbers with good ICP numbers is (usually) a good thing and likely means everything is working good. Also that no two engines are likely to produce the exact same numbers EVEN when they are both running perfect. From what I have read it seems that the 470 or 490 Hz frequency seems to be a fairly commonly used freq. Is this just more to do with maybe long time computer industry standards? I know I said I really didn't need to know about the freq. but I am a curious sort of fellow. Is there a simple explanation for this? What I mean to express here is I would think there are any number of other frequency's that (could) be used. Or are we into the (this is what's allotted for the purpose) sort of thing, Like with radio frequency's? Any further comments appreciated. This free education on the FTE site is a GREAT thing! Specially for an IDIOT like me! LOL I am sure I have some other questions I would love to ask but figure you guys need a break from me and my long posts right now :0 Thanks again... DDT
 
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Old 02-13-2018, 12:38 AM
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IPR

P.S. I did indexing and spacing when I wrote the above post. Guess it only works if you go to GO Advanced button. I also tried to insert an emogy but that didn't seem to work either. Maybe I need to have a higher usage rating or be a paid member?https://www.ford-trucks.com/forumhtt...ies2/wink2.gif
 
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Old 02-13-2018, 12:40 AM
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Talking IPR

P.S. I did indexing and spacing when I wrote the above post. Guess it only works if you go to GO Advanced button. I also tried to insert an emogy but that didn't seem to work either. Maybe I need to have a higher usage rating or be https://www.ford-trucks.com/forums/i...ons/icon4.gifa paid member?
 
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