[ottersox]

97 F250 7.3 - I have KOEO codes p1283, p1662 and p0381, and a no start issue. There were no codes stored on the PCM; I just have the KOEO codes. I’m using the AutoEnginuity tool, and I know that I have low ICP (175 when cranking). I checked The ICP sensor and it’s ok. When I put 12v to the IPR, I get good pressure (2,400 psi). i checked the voltage signal while cranking and get 9.8 v or so to the IPR. IPR duty cycle is very high at 54.68. I checked the wires and dont see any abrasions. Also buzz test passed and sounded great. Am I pretty much down to a new PCM?

This problem started with slight misfiring, then bad misfiring, then no start...

I assume that the p0381 is a bad glow plug, so Im not worried about that for now.

 

[White95f250]

The IPR is not 12v. You may have fried it giving it that much power.

If you have low HPOP pressure then i'd look at that a little closer.

Do you get any white smoke while cranking?

 

[ottersox]

I did a 12v test on the IPR that was recommended by “DieseltechRon”. He’s got some great YouTube videos. No white smoke while cranking. I think the injection control pressure is too low for the PCM to allow fuel flow. The 12v test on the IPR shows that it’s capable of providing adequate pressure. I Think it’s not getting the right signal from the PCM?

PS you’re right - if I put 12v to the IPR for very long it would fry the solenoid. Hope I didn’t do that! However, my no start and low ICP pre-date that test...

 

[White95f250]

Correct, IPR is a controlled bypass valve that when left open it relieves too much pressure and doesn't allow HPOP pressure to build.

Did the ICP connector have oil in it? There's a lot more involved to fully test the IPR. It's an electromagnet that fails over time due to heat and many temperature cycles. It may work with full 12v applied but may be too weak to handle anything below that.

I doubt it is signal related since high IPR % and low ICP readings indicate failing HPOP. You could have a weak starter or bad battery connections that do not allow the motor to crank with enough power to build pressure.

 

[ottersox]

Thanks! My battery voltage does run down to ~ 9.8 v when cranking. Maybe I should check connections or charge/replace batteries and also remove IPR and check... I don’t know how to test hpop, but I think if the IPR can crank out 2400 psi, it should start? My understanding is that hpop provides volume, IPR provides pressure, correct?

i appreciate your time and help!

 

[White95f250]

The HPOP is just a pump that provides continuous pressure and volume. The IPR controls a bypass that bleeds off pressure when it is not needed.

Get those batteries charged and make sure the terminals and connections are 100% clean.

 

[ottersox]

Thanks! I think those batteries are shot. I’ll get new ones in and report back. I might rebuild the IPR just for fun!

 

[ottersox]

I replaced the battery and put in a new Motorcraft IPR. No improvement in injection control pressure when cranking. Interestingly, I noticed that the KOEO codes that I got, p1283, p1662 and p0381, go away when I unplug the ICP sensor.

im thinking I’ll replace the ICP with a cheap aftermarket one just to test it. Seems like maybe either it’s bad, or the harness is bad.