Just bought an 03 6.0. Has 135,000 miles. When I got it it would hesitate and be low on power when driving. Truck was also starting very hard when warm. Would take 3-4 attempts to start. Removed icp and powered IPR. Found air leaking out of filter housing. HPOP was leaking.
Replaced hpop, oil cooler, and deleted egr cooler. Rechecked for air leaks and did not hear anymore. Put a few hundred miles on truck and it starts better than before and has full power now.

Problem is when warm after sitting for 15 minutes to an hour it takes a few seconds to start and than sounds like it's not running on all 8 cylinders for a couple more seconds. Does not set and codes but need to figure out why it does it. Could glow plugs cause this?


ficm voltage is 48.2 volts when starting
Icp pressure is at 1100 when it happens
Ipr is mid 30%


Jacked the front of the truck up and let it sit for an hour after it was hot. Truck wouldn't start. Pulled the oil filter and watched the reservoir fill. Filled fast but had lots of air bubbles in it.
Put filter back in and cranked it a few more times.
Started a couple times but died. Finally got it started but sounded to be running on 4 cylinders. Ran for about 5 seconds like that than oil pressure gauge finally came up and than it started running normal.

No codes still

Air tested the hpo system again. No leaks with IPR commanded.

Any ideas? Need some help on this.

 

I would look up the bubble test and see if you have any injector issues. Its basically as easy as removing the upper fuel filter cap, removing the filter, letting it fill with fuel, turning the truck over and watch for bubbling. If you see bubbles you have an injector that has failed and is letting exhaust gasses through it.

In my experience bad glow plugs (rare they go bad) throw a code.

My truck incidentally had a bad HPOP that I recently replaced. Ran great and then I found 4 bad injectors about 1k miles later. The less than 1 min I let it run it sounded like all the cylinders were not firing and idled real ruff. Also was very hard to start.

 

Alright. I'll check that out and see what I find out.

 

Also I noticed when I started it today before it warmed up it wouldn't rev up normally and if you held rpm's at 2000 it would just blow white smoke and smelled like raw diesel. So bad injectors could be it.

 

Check the O-rings on the standpipes & dummy plugs. You can also get o-ring kits from Sinister diesel for about 8 bucks a kit, Then pull your injectors one at a time, lay out some paper towels, take the little hex head bolt out keeping the orientation the same as you lay the pieces out. Next remove the spool valve again making sure of how it goes back together cause one side is longer than the other. Get some brake cleaner or WD and a small piece of 600 grit wet/ dry sandpaper and lightly clean the spool valve by twisting it in the sandpaper. Reassemble the injector take one of your kits (8 required) and put the new orings and copper washers on. Before you oil em up and slide back in check the injector cup in the head for old copper washers,dirt,parts of orings and any thing else. reinstall your new injector. Oh ***** I almost forgot on mine I also cleaned the nozzle w/ 600 paper all the way out to the very tip. now you can install your semi rebuilt injectors in and smile you just saved your self $2500 cash. hope this helps

 

03s don't have stand pipes or dummy plugs. Just nipple cups and the branch tube oring.

 

They do still have standpipes just no dummy plugs. I air tested it with the valve covers off and had no air leaks.

 

Did the bubble test with the engine cold and hot.

Had zero bubbles either time.

Checked fuel pressure and it was 67psi at idle.

Seems to run rough when on high idle. When you try to rev it to 2000rpms it just blows smoke and won't rev any further.

Any more ideas?

 

What are the ICP and IPR values when reving to 2000 rpms? Is it the 1100 psig and 30% values you mentioned earlier (and these values hold steady when trying to increase the rpms?)?

 

ICP is 1120
IPR is 35.5

Will increase if revved higher.

Seems to rev normally when done right away. Longer it idles the worse it gets.

 

Maybe time for a cylinder contribution test. The bubbles in the oil when filling the oil filter bowl doesn't sound normal either.

 

That's my next step. Need to find a scan tool to borrow to do that. My OTC Genisys can't do that test.

Not sure on the bubbles in oil filter housing.

 

Brought it in today to a small shop and they did a cylinder contribution test. They found no problems and said everything was even for the injectors.

Not sure what else to check?

 

They also said it had code p1378.

 

On a 2003 can they be air tested at the icp and commanding the ipr on. Does that check the whole system? That's how I've been doing it but now I'm wondering if it needs to be done at the oil rail under each valve cover.