2004 6L no start
 

Have an early build 2004 6L F350 Dually with a crank/no start problem.

Background: truck has over 200K. I monitor it with Scan gauge II. about two or so months ago my truck started be hard starting. it would start but only run for a few seconds then die. after a few trys and giving it some throttle it would run and continue to starbtand run fine until the next morning when it would hard start again.

Problem: last week it died and I had to be towed home. 'while waiting for the tow I saw that the ICP would not build above 350psi. so put in a new Motorcraft IPR. pressure would build to 1600psi but no start. saw that ICV was low so changed that. Still no start. Stats are: Ficm 48v, IPR 85%, ICP 738 (now), Sync !, ICv .24.
,So I Air tested with 110lbs in the ICP (yes in the back of the motor) . I can hear a leak seems equal on both sides. when I power the IPR the air leak Hiss dissappears. I assume I have a high pressure oil leak but not sure where to start the head and injectors (which have all been replaced in the last few years) or remove the intake and look down there.

any input will be appreciated. This is my primary work truck so I am dead in the water until I get it fixed

Thanks in advance,
Tim

Does hearing the air leak and having it completely go away when I power the IPR seem like the symptom of a high pressure oil system leak or is it just normal. Really second guessing my self here.

The ICP volts at .24 mean you really DON'T have the needed 500 psig of pressure to start. The indication of 738 psig is an inferred number. If you installed an aftermarket ICP sensor, I would change that out again - I have found most aftermarket sensors to be unreliable. Same thing w/ the IPR valve.

Yes, when doing the air pressure test of the high pressure oil system you will have an air leak until you close the IPR valve.

When doing the air test, be sure you remove the oil filter and listen for leaks there.

It sounds like an HPOP issue. If it is, the only HPOP I would recommend is the upgraded one from DieselSite. It is expensive, but worth it.

Thanks bismic, opening the intake today

I installed a BoTech rebuilt Hpop in my truck. Replaced the IPR with a brand new Motorcraft. Used a new aftermarket ICP. Also, when I had the pump out I air tested the system from the end of the J tube and did not hear any leaks. I am still only getting about 460 PSI. Don't know where to turn next. I have got to get this thing going. I'm tired of renting.
As a separate issue, I'm not getting any Sync or RPM signal. I will be checking out the wiring to the cam and crank sensors.
Any thoughts will be greatly appreciated.

Aftermarket parts have a significant potential for early failure, or even being bad out of the box. This is true with ICP sensors, IPR valves, and HPOPs (the exception is the upgraded DIeselsirte HPOP and the upgraded one from CNCFab) .... as well as a lot of other OEM parts are way better than aftermarket.

All you can do is compare the ICP voltage on the new with the pressure to determine if the sensor voltage is being used by the PCM. If voltage is low, then do an air test again. Then do a bench test of the IPR valve (even though it is new-ish).

best of luck.

already bench tested the IPR (went through 3). Icp voltage looks good about a quarter volt but am going to put it all together and unplug ICP to see if that might start it. If it does then bad ICP. what do you think? what do you mean compare ICP voltage with the pressure to determine if the PCM ...? the il pressure is consistently about 460 when cranking.

The proper "zero" voltage for ICP is about 1/4 of a volt. That is only one check. The sensor is designed/ranged for maximum (full scale) 5 volt output. Ford has software in the PCM where the sensor voltage output is converted to psi. I can post the approximate relationship (it is from the Workshop manual). You should check it against that.

Some aftermarket ICP sensors do not have that same calibration profile (because they are cheaply made). Some failed ICP sensors will lose the proper voltage profile (electrical short to power or ground or failed electronics in the actuator). If the PCM thinks the voltage is bad, the PCM will infer an ICP pressure value.

Did you hook up air to the IPR valve and verify no flow when the valve was closed with 12 volt power?

https://www.ford-trucks.com/forums/attachment.php?attachmentid=175466&d=1487989263

Oh, and I definitely am not a fan of BosTech 6.0L HPOPs .......

40% negative (granted only 7 reviews ..):

yes connected air to the IPR and charged it with 12 volts, it closed