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2003 6.0 Low ICP at WOT

373 Views 8 Replies 3 Participants Last post by  Weatherlite
Welp I'm beyond stumped on this truck and I really need some help. After reading and researching for literal weeks on end, no one seems to have an issue like mine.

So, I got a 2003 6.0 powerstroke that had an hpop fail on me last summer, I replaced it with a reman Bostec pump, along with new ipr, new icp, stand pipes, injector o-rings, oil rail nipples & seats, j tube connector ect. Normal hpo stuff. Truck was having hard start issues eventually turned into a no start even cold not two weeks after with low ICP (indicating probably a leak). I ended up ripping it down air testing the system (commanding ipr shut) and hearing a leak in the valley by the pump. Annoyingly, Bit the bullet took the pump back out found a melted nylon ring in the J-Tube and the pump leaked air out the front seal around 70 psi shop air. Contacted the company and they warranted the pump for me. I bought new stand pipes, new j-tube (AGAIN) and put in another pump just to have low ICP once again.

**** HERE IS THE CATCH. From my basic knowledge of these trucks I knew the last pump was failing & or a HPO leak, due to to high IPR at idle and low ICP. But now, the truck has 17-19 % IPR at idle with ICP of 580 (in spec I believe). To me that's indicating a strong pump. Would start no problem around 180 degree oil temp. Run's fine no lumps or bumps. BUT, low ICP at WOT makes no more than 1200 psi ICP at 85% IPR. Which is quite odd considering truck has plenty of Low end power and generated 30 psi boost. Today I beat the DOG out of it on the way home hoping to bleed any air out of the system getting the truck over 200 degrees. I shut the truck off and my stomach turned as I once again had a "Hot crank no start" only generating 350 psi at 85 % ipr. It eventually fired which was a relief, since I have to get to work tomorrow lol. But WTF is this things deal! Any help, tips or insight is very much appreciated.

Only thing that makes sense to me is there is some how a leak in the system STILL, and it will only leak over a 1000 psi oil pressure, Maybe I cant find the leak with 125psi shop air. I truly don't know anymore.
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Since you've been reading forums for a while you've probably read what I'm about to type before.

What are you using to monitor the engine PIDs? Did you use Motorcraft parts or aftermarket? When it wouldn't start did you try disconnecting the ICP and then attempting a start? If so, what happened? And finally, were any codes thrown? Also, if you don't mind, some readings might be helpful. Can you get the following specs at KOEO, cold idle, hot idle, and hot running down the road (use a helper so you're not distracted by the screen....or take a quick screen shot so you're not trying to write things down while driving):

Barometric pressure
MAP (sometimes called boost)
EBP Exhaust backpressure
ICP pressure
ICP voltage...yes, get both the pressure and the voltage!
Coolant temp
Oil temp
VGT Turbo %
Battery voltage

Some of those don't seem like they would have an effect on your situation but just humor me. lol Oh, and if it has a no start condition again then definitely get all of the above when you're cranking, but if possible also get these extra PIDs:

FICM Logic
FICM Vehicle
Injector pulse width
Ambient temp
Cam/crank Sync

If I've forgotten anything hopefully someone will come along and add in the extra.
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Thanks for getting back to me, so I did use aftermarket parts. Aftermarket icp, ipr and stand pipes. I couldn’t get oem parts as I was borrowing my works lift and in a pinch. I got everything at local automotive places. For a monitor I am using a Livewire Ts, as I don’t have a scan tool. However I contacted a buddy who’s gonna come down some point this week with his Gameboy, and see if we can find out a thing or two. I haven’t tried disconnecting the ipr and starting it but I will give that a try today! I’m gonna wait for my buddy’s scanner to give you all the specs as there is more info and it’s more accurate. This morning when the truck was cold. IPR showed 85% at barely a quarter throttle and sometimes wouldn’t fall back off to 30-32 % at idle. Scared me as I thought my ICP was gonna plummet and the truck would stall as it did the first time. However it was fine once it warmed up and icp stayed around 19% while off throttle holding around 600+ icp. Truck boosted ok and boogied at 25psi just a little sluggish from its usual.
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Weatherlite corrected his post .................. you do not disconnect the IPR, you disconnect the ICP.

Also, I'll quote my post from FTE here (below)

Assuming a melted nylon component, I would be checking/verifying the peak oil temperatures - especially when you "beat the dog out of it", and the coolant was over 200*F. I guess it also might be possible that an HPOP issue/failure was adding a fair amount of excess heat.

Not a fan of Bostech, but as mentioned above, maybe excessive heat is a root cause. There could also be an issue with the IPR valve. Lastly, are you sure that your oil is not "fuel diluted"? Diesel in the oil can cause issues with reaching proper pressures in the high pressure oil system.

Where you buy these high pressure oil system components is VERY, VERY important IMO. Lots of cheap counterfeit parts being sold.

Leak testing is best done hot, although the high temperatures make it hard to do so safely. Be careful if you do, you can burn yourself.

You should be able to find the leaks with 125 psi shop air. If you are not convinced, then go to 150 psi. My absolute max top air pressure would be around 175 psi.
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Also, getting a good scan tool is as easy as downloading ForScan Lite to a smartphone for only a few dollars, and buying the appropriate OBDII adapter for the device. Torque Pro is also a good scan tool. A good adapter can be around $80, a cheap one around $40. It is a requirement for a 6.0L owner to have, unless they are wealthy and have an HONEST and FABULOUS mechanic. What you can get with these two choices is a very capable code reader. You don't get that with other "inexpensive" scan tool choices.

The Livewire TS should give you the ability to retrieve some engine parameters. It will not scan codes very well, if at all.

A gameboy isn't going to retrieve codes either ..............
Sorry I should have been more clear, the coolant temp didn’t exceed over 200, the oil temp was. Most I’ve ever seen was oil temp wise was 223 on a 95 degree day at 70-80mph on the highway. Never seen hot coolant temps usually floats at 170. As for disconnecting IPR, I thought that sounded funny. I know most people try disconnecting ICP sensor. I was going to try that yesterday but my truck is an 03 and it is so far back in the motor can’t quite get my mit in there behind the turbo. Burned the SH*T out myself trying and gave up. Ill see if I can get it when it’s cold and drive it home, Park it, start it. I actually just put fresh 15w40 rotella and filter yesterday. I’m almost positive it wasn’t diluted.
Hah, the game boy was a joke for my buddies fancy snap on scanner. I just want to use a nice scanner to manually tap into and command the ipr to open and shut to see what happens. I’m almost positive I’ve got a leak at this point as I did the air test while the oil was room temp which is bad on my part.
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Two quick thoughts for you. If you get time and a few extra dollars to get good connectors you may want to consider extending the ICP and IPR harnesses so you can disconnect them from a more practical location. On several '03/early '04s I have done this and placed the connectors sort of below the FICM by the injector harness. It was life saving on one of em when they had another problem later on and disconnecting the IPR was one of the tests...though it still sucked because the ICP sensor turned out to be needing replacement. lol But definitely use quality, waterproof connectors and copper wire. And you will want to solder the connections and use dual wall (sometimes called adhesive lined) shrink tubing to seal the wires. I've seen enough corroded factory wire to know you want to really seal any repairs/modifications.

My other thought is on the air test. The '03/04 has the J-tube under the HPOP cover. When doing your test if you hear a leak coming from under the cover (sound coming out of the turbo oil drain return in the HPOP cover) it might be from several locations under there but you will have no way of knowing which....the STC fitting on one end of the J-tube, the o-ring between J-tube and the pump, D-ring between J-tube and HPOP cover, and o-ring under the pump are the ones applicable here really. Anyway, what I did was make a valve with a barbed fitting on the end so I had something solid to grab and press down with. On the end of the barb I placed some 5/16 hose and cut it maybe 1/4" past the barb so it wouldn't flex. Next I shaved the end so it was a little tapered. I was able to place that into the hole on top of the J-tube and apply air to do my test. You will be able to more readily figure out which seal is bad this way....but if there is no leak doing it this way even though you did previously have one then you now know the leak is the D-ring because that's the only one not being tested with this method. Word of caution though. Hold it down VERY securely. I didn't quite have it seated right and it moved with full pressure being applied and I wound up with a face full of oil spray. lol
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