[Stricko88]

Hi guys, have a truck in the shop here at the moment that throws the dreaded P1211 under load. I have scoured the forums and nearly all posts point to a loss of oil pressure triggering this. I have done all of the usual diagnostics, and when driving it I recorded all live data. What is happening is at around 75mph if I point the truck up a hill and put the foot down, it doesn't appear to want to downshift and slowly loses power before throwing the engine light.
Live data indicates that this is actually from high oil pressure (3500-3800psi). On the graph the duty cycle on the IPR builds gradually from 45% to 65% before throwing the engine light and dropping off sharply. Oil pressure builds to about 2600psi, then drops to about 2000psi before a spike straight up to 3800psi before throwing the light.
I hope this makes sense to some of you guys, I am one of the only F250 techs in Australia, so finding information locally is very difficult.
IPR is brand new also as the solenoid was quite hot looking and has been in the truck for nearly 200,000miles

 

[RT]

Do you have any way to monitor fuel pressure during a test drive? The PCM will increase IC pressure in response to low fuel pressure as a way of maintaining power. If you have a restriction, the additional demands of going uphill (Australia has hills???) might drop the pressure to the point you get the increase in IC pressure you are seeing.

 

[Stricko88]

Fuel pressure stays steady at 55-60PSI under all conditions. I have noticed that when I road test the truck, when I load it up (75mph up a hill) the duty cycle command is gradually increased from around 35% to 65% however the oil pressure stays stagnant at approx 1900psi without increasing. So it is like the pump can't generate the commanded oil pressure when under heavy load.

 

[RT]

Wait - it stays at 1900 psi without increasing like you say in post 3 or it builds to 2600, drops to 2000, and then spikes to 3000 like post 1? It could be an ICP sensor that is wonky.

 

[Stricko88]

Sorry mate, it is hard to put graph information into text. When I stand on the accelerator under load (overdrive 75mph+ up hill) The pressure will increase initially to about 2500-2600 before settling at 1900-2000psi, even though the IPR duty cycle is increasing. Once the power drops off enough for the transmission to downshift we are seeing the pressure spike, as the pump is suddenly exposed to much higher RPM with the IPR still at 65%. The high pressure makes me think that the pump is ok and the issue is possibly an oil bypass fault in one of the injectors? Is there any way I can post up some graphs of the live data?

 

[klhansen]

What are you using to look at your graphical data? You can post up an Excel file or a .csv file here.

I'm wondering like RT if the ICP is giving you wonky signals. Could be caused by an intermittent problem with the wiring that might be happening when it downshifts.

 

[greenskeeper79]

sounds like the IPR cycles once and then gets "stuck" in a position that bleeds oil psi at 1900 even though duty cycle is increasing. Once the transmission downshifts the IPR can't correct, oil spikes, PCM shuts it down.

 

[Stricko88]

The IPR is new, and I can drive this thing around for weeks without problem as long as it is not under heavy load, the IPR, ICP, EBP, MAP, all read faultlessly until I really make the truck work. Only other thing I did note is that the maximum boost pressure I have been able to achieve is around 19.4psi, does this sound right for a stock truck?
I thought maybe a dud ICP as this truck originally had a DP Chip (made in Australia, basically splices the ICP harness and sends false signals to the PCM, quite dodgy) However I swapped the ICP with a known good one and got the same fault. I'm wondering if I am getting a HP oil leak through one of the injectors under heavy load? It would explain the loss of power and black smoke matched with the low oil pressure? I will dead head the pump today, but I think simply because under normal driving conditions it can generate higher pressures that it will be ok.
If I put a pressure gauge in each oil rail will that indicate which side may be leaking?

 

[blue99stroker]

Have you removed the Icp adjuster? It's junk.

It's possible you have a hpo leak. You can dead head each rail to see if you have a leak.

The pump might be on its way out. They always show their health under hard load.

 

[Stricko88]

First thing I did was bin the ICP adjuster. I will dead head the pump and see what it makes under crank, then isolate each bank. Is it easiest to just blank one of the outlets on the side of the HPOP and tee into the other?

 

[klhansen]

Did you check out the wiring to the ICP sensor? Since someone had spliced a gizmo on it, there might be an issue with the connector or the wiring bundle.

The way to check out the heads for HP oil leaks is to block off each hose by pulling it off the fitting at the head. If you start with the right side head (notice that I didn't say passenger side since you guys have RH drive vehicles down there), you can leave the ICP sensor in place to get the pressure readings. Then disconnect the left side hose, remove the ICP and put it on the end of the end of the hose to monitor HP oil pressure. Then disconnect and block the right side hose to check the HPOP/IPR combination. In order to isolate the problem to either the HPOP or ICP, the ICP needs to be swapped with a known good one. and the deadhead test done again. You can get block off fittings at a hydraulics shop that carries Eaton Aeroquip fittings. What you want is STC (snap-to-connect) fittings.

Here's a link to the STC Catalog, and other info. http://www.thedieselstop.com/forums/f47/homemade-hpop-test-plugs-262025/#post1929210

 

[Stricko88]

I replaced the ICP pigtail when I deleted the ICP "tuner" and under normal driving conditions the ICP, IPR, MAP, EBP etc all read normally and flow as expected. It is only under heavy load that this problem is occuring where the pump just can't supply any HP oil greater than around 1900-2000psi. Under normal driving it will happily supply up to around 2750psi at a 43% duty cycle. My only other thought is that under heavy load (75-80mph uphill) that the transmission won't kick down correctly which may be causing the pump to struggle to supply the pressure requested? Seems a bit left field but it is just another thought I had last night. I have tried to attach the data file as a pdf, there is a yellow line on the graphs which is when the CEL was triggered, as you can see on the IPR pressure graph, prior to triggering the pump is struggling even though the duty cycle is climbing higher and higher.

 

[klhansen]

Something's wonky with the ICP circuit. I'm thinking a short to Vref, because the ICP signal voltage isn't supposed to go above 3V
Here are the parameters from the Service Manual.
Name: ICP
Circuit #: 812
Wire Color: DB/LG
Key Off: 0v
Key On: 0.2v-0.4v
Low Idle: 1v
High Idle: 2v
Operating Range: 0.1v-3v
Comments: (Min 0.83v req. for starting)

 

[Stricko88]

Thanks for the info mate, I will check that out first. Thanks so ,much for the help so far guys, it has been a big help

 

[Stricko88]

Something's wonky with the ICP circuit. I'm thinking a short to Vref, because the ICP signal voltage isn't supposed to go above 3V
Here are the parameters from the Service Manual.
Name: ICP
Circuit #: 812
Wire Color: DB/LG
Key Off: 0v
Key On: 0.2v-0.4v
Low Idle: 1v
High Idle: 2v
Operating Range: 0.1v-3v
Comments: (Min 0.83v req. for starting)

The ICP can still read higher than 3V though? That would be how it would inform the PCM that the HP oil is higher than spec correct? The only time that the ICP exceeds the 3-3.5V range is when the IPR reaches 65% duty cycle and spikes the pressure outside normal limits. I have rechecked all wiring and cannot find any shorts. Gauges are going into the cylinder head today to monitor actual rail pressure when under load. This should hopefully indicate weather I have a mechanical problem or a signal problem.
Also over the weekend I removed the intake tube and found a large split on the underside, so for goodness knows how long this turbo/engine has been sucking air after the air filter, which may be why we are having low power under heavy load also

 

[klhansen]

The ICP can still read higher than 3V though? That would be how it would inform the PCM that the HP oil is higher than spec correct? The only time that the ICP exceeds the 3-3.5V range is when the IPR reaches 65% duty cycle and spikes the pressure outside normal limits. I have rechecked all wiring and cannot find any shorts. Gauges are going into the cylinder head today to monitor actual rail pressure when under load. This should hopefully indicate weather I have a mechanical problem or a signal problem.
Also over the weekend I removed the intake tube and found a large split on the underside, so for goodness knows how long this turbo/engine has been sucking air after the air filter, which may be why we are having low power under heavy load also

The way the system works is that the PCM reads the ICP, and controls the IPR. The only time the IPR should reach the 65% duty cycle limit is when the HPOP can't maintain the pressure that the PCM is calling for and reading from the ICP. The ICP is a feedback control for the IPR. During engine development, Ford (International) originally tried to control the IPR without an ICP sensor, but it wasn't controllable enough, so they added the ICP sensor.
What seems to be happening with yours is that the pressure is overshooting the desired mark for some reason. It could be that the dump port from the IPR (thru the edge filter) is restricted and the pressure can't bleed off fast enough, causing the spike.
Here's a good resource for the HP oil system on the 7.3L Powerstroke. High Pressure Pump Supplement Diagnostics

 

[Stricko88]

Thanks again mate. Have just spent 2 hours test driving with a mechanical gauge in the LHS oil rail as well as monitoring ICP, IPR, IPR% & MAP. It performed flawlessly, no engine lights whatsoever, but when I pushed it hard (140kph plus, which is illegal in our country by a long shot) the ICP voltage rose to 4.83V which the PCM reads as close to 3500psi, however I didn't notice it this high on the mechanical gauge. I'm wondering if the factory ICP physically cannot operate under such conditions? As I said originally, the truck had an ICP tuner on it when it first arrived, so I'm wondering if the only way that the stock truck is capable of what this customer does, is if there is a "chip" sending an incorrect ICP signal back to the PCM effectively masking the fault. I can only imagine the load required to propel a 4T truck up a hill at 150km/h (95mph)

 

[Stricko88]

Blocked each side of the engine yesterday (removed the HPO braided hose and blocked it off at both the pump and engine) I then cranked and monitored the ICP, IPR and IPR%. After doing this on one side and recording the results I did the same for the other.
RHS Bank Block
RPM - 557
Inj% - 15-42%
INJ Psi - 0-2417psi
ICPV - 0-3V

LHS Bank Block
RPM - 0
Inj% - 15-65%
INJ Psi - 8-19psi
ICPV - 0.26V

Looks like I have a HPO leak on the LHS bank somewhere. Next step is to pull the covers and cold start the engine to see how much oil is discharging through each one.

 

[Stricko88]

I would like to thank everyone for their help and patience in working through this with me. It seems we have traced the fault, and it has nothing to do with the engine! After going back and forwards with the customer we established that he has not had this issue before, nor any symptoms related to any faults in the HPOP system. Which led me away from the engine and towards the transmission (which had been rebuilt not long before the truck came to me) After convincing the transmission guy to strip the auto and open the torque converter we found that the front plate was blue from heat. I pulled the oil pump and found the rotors warped, which was giving us a cross flow leak across the oil pump. So essentially the converter has been locking up all the time, giving low power, worsening when hot, as well as stalling the motor in reverse and manual second when hot. Auto trans should be back at my shop tomorrow to put back into this truck and hopefully get it back to the customer.

 

[klhansen]

Thanks for closing the loop on this. Interesting that the tranny caused the problem with ICP reported pressure.

Glad you got it tracked down.