I have a 2002 F-550. It sets the dreaded P1211. It is all stock. i did manage to get the live Data.

@2600 RPM ICP duty cycle was 65
ICP 1568 & volts @2.01

I had just changed the oil & also replaced the fuel pump because of noises with it.

I had the code before then & Live Data was


RPM 1786
37 precent duty Cy.
2340 Icp

Help . Oh by the way the stealership told me it was probably the HPOP. I replaced it. Checked all wiring. Checked for biased ICP sensor & had another IPR that came off another truck of same yr which was fine running and still getting code

 

I don't have any answers for you, it sounds like you are doing all the right stuff.
Very interested in hearing what the final answer will be.
Did you try swapping that ICP sensor as well?

 

65% duty cycle on a stock truck is a bit high. My guess would be to first start with the IPR, not the HPOP itself.

 

At WOT (3400rpm) in park (no Load) the IPR should be less than 65% and ICP greater than 1800 psi.

Just from looking at that reading you posted Duty Cycle will be above that and I would bet ICP below 1800. Fisrt thing is to check the HPOP for leaks a small leak can cause a 1211 to be set sometimes

 

Oh I forgot to mention, This was done while driving the truck down the road w/load. As I said, I did replace the IPR and sensor. Now i'm really at a loss. I drove it about 14 miles before the code was triggeredunder WOT. The second was done at 1/2 throttle going about 5 miles

 

Either that or I'm thinking that the HPOP is simply worn out and unable to generate enough volume to keep up with demand.

 

Well the HPOP is new. There are no leaks. So far though I pulled the valve covers and found 2 injectors not putting out oil through the oil spouts. I will have to replace thoses injectors then try it again and see if I can regenerate the code. If so i am going to try something else.I will let everyone know the results as I go along. The results of the previous postings were done driving down the road w/load. Not without load. I did do a test no load and everything checked alright. I don't know why Ford doesn't do a load test to come with their specs. That is where my problem lies.

 

Do you have any way of doing a cylinder contribution test?
A lot of the tuners that are on the market are capable of this. Even if you have to borrow a friend's tuner it will work for the diagnostic portion.
On my Diablo Predator it's under diagnostics, then diesel fuel, select show all data, and then scroll down to the bottom where you see each cylinder listed with a % reading of rpm drop per cylinder. The one or ones with the highest percentage of rpm drop are the ones with the bad injectors. Don't worry about anything less than 2 or 3 %.
With that done you will know exactly which injectors to pull and replace.
While you are in there retorque all the rocker arm pedastals, they like to work thier way loose at the bolts. 18 ft lb.
And retorque all the rest of the injectors that are remaining at 120 inch lb.
Once that is done your engine will sound much quieter and tighter. (Personal experience speaking. )

 

Yes I performed the contribution test. It passed. Also I checked the injectors and found that the #1 & #4 was not putting oil out of the spout. I replaced them and after that I started the truck. They now have oil coming out of the spout.The treuck runs much smoother and starts easier now. I did the contribution test again and it still passed. I then did an injector buzz test and found that the now there are others hi to low is open but initially it everything was fine. Just wondering now if it is the IDM

 

Well I replaced the IDM and now I got the injectors codes all taken care of. But now back to my original P1211. I took it out for a 200 mile tour. everything was fine into about half of that. I got the code light again. I was stomping on the accelerator pedal. I looked at the recordings that set the codes and I am still getting 65 percent duty cycle from the IPR. Is it now possible that the computer is bad. I 've already replaced everything that I can think of. HELP

 

ive done everything you have ipr,icp,hpop, and a new computer. nothing fixed it but the bulb having black tape over it should have done that a few thousand dollars before because truck always ran great just would always get the light(p1211) but no more 12000 miles on the tape and truck runs great from stock to 80 econo now.

 

Well that's fine. But now when it comes on I start losing power and the throttle response is not there. As yesterday i could barely make 10 mph after the light came on. The only 2 things that I haven't tried is to replace the harness even though it checks out and the computer. Still at a loss here. even called Ford on this and they can't even come up with a reason.

 

Just wagging here but have your checked the pressure in the LPOP? could the HPOP be starving for oil?

With a gauge in place of the EOP sender there should be a minimum 12psi in the HPOP reservoir. Also if the anti drainback check valve has some crud stuck in it it could be bleeding off.

 

Well guys so far today I did a wot fuel pressure test. it turns out the possible reason for the P1211 is one of my fuel lines is collapsing. I have to pull the fuel tank to check inside of it . Maybe the intank screen is clogged creating all of my problems not the hpop

 

While you are checking for that sort of thing, there is also a screen built into the intake side of the fuel pump itself that likes to get filled up with crud. I replaced my fuel pump last year for low fuel pressure, thinking it was worn out, when in fact it was simply clogged up.
Since I had the new one already in my hand I put it in anyway.