[mbohnenkemper]

History...I'm running a early 99 with Jody Tipton 80 hp econo tune, stage 1 injectors, Beans d66 turbo with pedestal, and running the normal gauages and 4in exhaust system. There seems to be a knock and it kinda sounds like a injector but not for certain. My fuel pump and HPOP are stock so I ran the tool auto enginuity with RifRaffs documentations on testing the HPOP. Ony at the very top end on WOT doing close to 90mph at this point an 25 psi does the duty cycle go above the 65% However the injector control pressure does go above 2000 psi so Im confused on my findings. Can anyone help with the clarification? Not even sure if the HPOP is that bad and if that is what is causing the knock. Will Low fuel pressure cause the knock?

 

[RT]

Low fuel pressure is probably the number one cause of injector knock. I recommend all 7.3 and 6.0 owners run a full time fuel pressure gauge.


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[mbohnenkemper]

Fuel pump a hell of a lot cheaper that a new HPOP. New HPOP is on my list to get but change out with a bosch fuel pump is not bad at all. 100.00 new out the door.

 

[blue99stroker]

Is the knock at idle or while driving?

Single shots do tend to knock more than stock split shots.

Also check Icp numbers at idle they might be too high.

Your duty cycle and hpo numbers are not good. 65% means the pump is maxed. And you should be atleast 2500 psi.


It doesn't hurt to check fuel pressure though.

 

[ArcticDriver]

Fuel pump a hell of a lot cheaper that a new HPOP. New HPOP is on my list to get but change out with a bosch fuel pump is not bad at all. 100.00 new out the door.

Where did you find $100 out the door Bosch pump ?

Thanks

 

[mbohnenkemper]

I got the Bosch pump from advance auto for 129.99 then had 5 Bucks speed perks and found a online coupon that knock 40$ off anything over a 100 so cost me 98 with tax an all.
I changed out the fuel pump last night an no change. I can hear it idling the is a different knock that just started. Yes I agree the newer injectors are louder but this is a different sound that just started. I still think its a injector just not sure why. Buzz tested just fine. Oh an yes I knew the HPOP was being maxed out, its on my list to be changed out with a T500 but it doesn't max out till way up in the MPH. So its ok for the moment but yes it needs to be changed too. attached are some specs from auto enginuity per RifRaffs setup.

 

[klhansen]

A buzz test won't tell you much about whether an injector is knocking or not. All it really does is check out the electrical side of the injectors and by ear, giving you an indication of the poppet clearance.

BTW, can you expand your columns a bit on your recordings? Hard to tell what parameter it being shown when the all begin with ICP ... and get cut off.

Looks like you're getting just under 2400 psi with your IPR maxed out (although Justin at DP Tuner says the 65% limit is modified by tunes.) The 3000 psi reading probably occurred when you backed off the go-pedal and the IPR hadn't reacted yet to bleed off pressure.

 

[mbohnenkemper]

Either way still got that knock. I will see what I can do on the pdf's

 

[ArcticDriver]

When you change your fuel pump, should any fittings or seals be changed at the same time?

Such as where the fuel lines attach to either end of the pump?

It looks like the attachment from the tank line could allow air to suck in.

Thanks

 

[rustygold]

Question is you getting any smoke out the tail?

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[[email protected]]

A buzz test won't tell you much about whether an injector is knocking or not. All it really does is check out the electrical side of the injectors and by ear, giving you an indication of the poppet clearance.

BTW, can you expand your columns a bit on your recordings? Hard to tell what parameter it being shown when the all begin with ICP ... and get cut off.

Looks like you're getting just under 2400 psi with your IPR maxed out (although Justin at DP Tuner says the 65% limit is modified by tunes.) The 3000 psi reading probably occurred when you backed off the go-pedal and the IPR hadn't reacted yet to bleed off pressure.

Anything over 65% duty cycle is maxed out. The stock tune only lets it go to 65% though. When running an aftermarket tune, the duty cycle can climb higher than this, even though the needle is still in the same physical location as it would be with 65% duty cycle. Does that make sense?

OP... Does the knock sound like an injector missing? If you are hearing a single knock, it is probably injector related. You can pull the valve covers and disconnect each injector one at a time while the truck is running to see if the knock stays the same or gets worse. If it stays the same, that injector is the issue. If it gets worse, that injector was working just fine.

Also, how many miles since installing these injectors? If it is less than a couple hundred, you may still have air in the system which could cause it to run rough.

 

[klhansen]

Anything over 65% duty cycle is maxed out. The stock tune only lets it go to 65% though. When running an aftermarket tune, the duty cycle can climb higher than this, even though the needle is still in the same physical location as it would be with 65% duty cycle. Does that make sense?

Justin,
The way I understand the IPR to work is that the duty cycle is the amount of time that the needle is closed. The signal pulses 12 V rapidly to the coil pushing the needle closed and then releasing it back open. So 65% duty cycle would be closed 65% of the time and open 35%, resulting in an overall modulating position of the needle with time. So if the duty cycle can go higher with a tune, then the needle would be closed a higher percentage of the time, resulting in higher HPOP pressure output. A test pigtail with 12V applied across the coil would result in a 100% duty cycle and max out the pressure that the HPOP can supply. That's what the service manual says, and this http://www.thedieselstop.com/faq/9497faq/download/HighPressurePumpSupplementDiagnostics.pdf also talks about how it works.
Please correct me if that's not right.
Kevin

 

[mbohnenkemper]

Yes I get smoke out tail pipe when I'm on it (black) The injectors and new turbo were put on several months ago but under a year. It sounds like one injector making noise on drivers side. I didn't know you could take the valve cover off with the truck running let alone unplug the injectors while its running. I will have to try that this weekend. Kinda Leary about it but I'll do it.

 

[klhansen]

It'll run just fine with the valve covers off. Of course if you were to rev it much it would probably throw oil all over, but at idle it'll be fine. Just be careful when pulling the wire connectors off the injectors. The run at 100+ volts and that can bite you.

The other option is to find someone with an injector cutout box, which just plugs into the engine harness and can switch off individual injectors.

 

[rustygold]

If you know someone with a good scan tool to do a power balance test. I stopped buying injectors from a paets house. Down here we got ark fuel injection they can balance the injector flow so it's even across the board before you buy.

And good think on the no smoke because overfueling is the worst thing for a diesel.

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[mbohnenkemper]

I have the autoenginuity but I dont know if it will do what you ask. I'm still learning that thing, it does so much.
I will try to unplug the injector this weekend and try not to get shocked. I have been shocked by MSD 6AL before couple years ago.....Still recovering from that one.

 

[rustygold]

It should if you have the ford part not just obd2.

I use a flathead to take them off and on seen people do it with bear hands

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[mbohnenkemper]

I have the Ford Mod for the autoenginuity. Still trying to figure out all what it does. The thing is a monster. I didnt get a chance to do the injector unplug last weekend....Life happened. Will try here in the next few days. Unless anyone out there can shed some light on some of the settings of auto enginuity

 

[rustygold]

If it has it look for a power balance test, engine balance, or contributing test it's faster than taking off the valve cover and doing it one by one.

Now the test says to do it when hot but if the motor acts up cold I start there and test while hot.

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Justin,
The way I understand the IPR to work is that the duty cycle is the amount of time that the needle is closed. The signal pulses 12 V rapidly to the coil pushing the needle closed and then releasing it back open. So 65% duty cycle would be closed 65% of the time and open 35%, resulting in an overall modulating position of the needle with time. So if the duty cycle can go higher with a tune, then the needle would be closed a higher percentage of the time, resulting in higher HPOP pressure output. A test pigtail with 12V applied across the coil would result in a 100% duty cycle and max out the pressure that the HPOP can supply. That's what the service manual says, and this http://www.thedieselstop.com/faq/9497faq/download/HighPressurePumpSupplementDiagnostics.pdf also talks about how it works.
Please correct me if that's not right.
Kevin

Here is some information I have on the IPR that Patrick Feeley provided some time ago...

The IPR is an electronically controlled pilot operated pressure control valve. The basic components of the IPR are the: Body, Spool Valve, Spool Spring, Poppet, Push Pin, Armature, Solenoid, and Edge Filter (later ones don’t have the edge filter).

The IPR controls HPOP outlet pressure in a range between 450 and 3,000 psi. An electrical signal to the solenoid creates a magnetic field which applies a variable force on the poppet to control pressure.

OPERATION – Engine Off

With the engine off, the valve spool is held to the right by the return spring and the drain ports are closed.

OPERATION – Engine Start Up

Approximately 1,500 psi of oil pressure is required to start a relatively warm engine. If the engine is cold (coolant temperature below 32F), 3,000 psi of oil pressure is commanded by the PCM.

Oil flow through the IPR is as follows: Pump outlet pressure (red) enters the end of the body and a small amount of oil flows into the spool chamber through the pilot stage filter screen and control orifice in the end of the spool. The electronic signal causes the solenoid to generate a magnetic field which pushes the armature to the right. The armature exerts a force on the push pin and poppet holding the poppet closed allowing spool chamber pressure to build. The combination of spool spring force and spool chamber pressure hold the spool to the right closing the drain ports. All oil is directed to the pressure rail until the desired pressure is reached.

OPERATION – Engine Running

Once the engine starts, the PCM sends a signal to the IPR to give the rail pressure desired. The injection control pressure sensor (ICP) monitors actual gallery pressure. The PCM compares the actual rail pressure to the desired rail pressure and adjusts the signal to the IPR to obtain the desired rail pressure.

The actual oil flow through the IPR during engine operation is as follows: Pump outlet pressure (red) enters the end of the body and a small amount of oil flows into the spool chamber (orange) through the pilot stage filter and the control orifice in the spool. The pressure in the spool chamber is controlled by adjusting the position on the poppet and allowing it to bleed off some of the oil in the spool chamber. The position on the poppet is controlled by the strength of the magnetic field produced from the electrical signal from the PCM. The spool responds to pressure changes in the spool chamber (left side of the spool) by changing positions to maintain a force balance between the right and left side of the spool. The spool position determines how much area of the drain ports are open. The drain port open area directly affects how much oil is bled off from the pump outlet and directly affects rail pressure. The process of responding to pressure changes on either side of the spool occurs so rapidly that the spool is held in a partially open position and pump outlet pressure is closely controlled. The IPR allows infinitely variable control of pump outlet pressure between 450 psi and 3,000 psi.


So the duty cycle does not correlate to on/off time. It correlates to a magnetic force which is directly related to the position of the valve. At 65% duty cycle or more, the valve is in a location to pretty much block the drainage of oil.