Sooo frustrated... 6 months without my truck
 

6 months today. And it's sitting out in a field dead by a gas well just like it was 6 months ago. It has 60 lbs of oil pressure when I start it up, and it drops to pretty much nothing hot. I got my scangauge programmed so I can watch everything, and I still have no answers. It starts to miss, the ICP starts getting erratic and maxing out, then it quits while still showing good icp pressure and 10 lbs or so LOP. It shows 650 lbs while cranking, 48.5 ficm volts, sync, 23.5 icp volts koeo, and still no go. Figured it was the IPR, so I changed it to the tune of $429, and no difference.
I guess I start digging into the LPO to see why a new engine has no hot oil pressure. Wondering if there are oil gallery plugs that maybe the machine shop forgot to put back in and I didn't notice. I checked the oil filter drains and they're all good. So sick of spending time and money on this thing and getting nowhere.
If someone came and offered me what I have in the new engine, it would be gone. :-arrgh

The numbers highlighted in red are a problem, at KOEO it should be .18-.24 . Sorry to hear you are still having problems even after all that work.

Wrote that wrong. Supposed to be .23... not sure where I got 23.5 volts on a 5volt ref system. :-D
Ok, I'm an idiot. Not used to the scangauge, I was reading the "I" in ICP as a "1". It doesn't have 651 lbs, it has 61 pounds while cranking. Sheesh...


Now I'm not sure what to do... It made 3900 plus pounds when I floored it, so the hpop shouldn't be bad, but I don't know what else could be wrong. I did an air check yesterday, pushed 140 lbs of air in for over an hour, and commanded the IPR closed several times, it was pretty much quiet. I've had hpo leaks before and they were quite noticeable, this was quiet with just a slight difference when the IPR closed off. Going to wait for it to cool off and make sure I was actually reading 3900 lbs, not 390. :-)


The way I figure it, I've either got a LOP problem that's starving the HPO, or I have a HPO leak that's causing my low oil pressure when hot.
Sigh

Update... this is the first time I've had gauges when it's quit, so I'm learning a lot more. I just stopped out in the field and gave it a 10 second crank, and it only made it to just over 100lbs and .34 volts. I've never had anything less than .55 volts on any of the previous hpo leaks, so this has to be big.
3 questons for the learned folks on here...
1. If the hpop is bad, would it make full pressure when the engine was only half warm and floored, and almost nothing when warm and cranking?
2. What are the symptoms of a bad pump on an air check?
3. Can a bad hpo leak cause the low side to lose pressure?

Put a mechanical test gauge on the filter houseing. Test port bottom of houseing near the passenger side.
12mm thread to NPT of your choice, fitting available at most hydraulic parts places. Use the one that has the o-ring on the 12mm end.
45 psi min. 55 to 65 good.

1. Yes thicker , colder oil will produce more pressure.
2. Leak heard form both sides, or possibly no leak at all. Depends on how its broken.
A pump that bounces hi/low at a fairly even pase could be a sing of a broken section, the pump is a basic piston style pump. Its also possible the drive gear bolt is not tight enugh.
3. Yes a big leak can drain low side pressure.

But im not learned so all bets are off.

Got a gauge hooked up to it, and it has 60lbs cold, and next to nothing hot.


Latest update...for those holding their breath, wondering what the outcome will be... :D
Just went out in the dark and tried to start it cold, it won't start, and won't build ICP. So it's rapidly getting worse. Just found a "new" HPOP on kijiji for 200 bucks and I'm buying it. Even if it isn't my problem, it will make a nice conversation piece and I'm not going to let it slip away for that price.


Moe, do these things break, or just wear out? Now I'm thinking back to the runaway 6 months ago... the pump was fine before that. I never took it apart because it looked very difficult, and I suspected no problems with the later style pump, but maybe it ate itself up in the runaway?

Ive seen a few broken ones, saw 2 completely locked up and took out the timing gears on cam and crank.
Ive see a few with a couple of 100k miles too.

Have you checked the lpo regulator? Very possible the fuel laden oil wore the oil pump clearances too loose.

No I haven't. It's the next thing on my list. I cranked it over this morning bright and early, and got about 15lbs lop while cranking, and it wouldn't make 200 lbs hpo... makes me think a hpo leak is causing the low lpo pressure. Or maybe I have 2 problems going on at once, it wouldn't be the first time.
I checked the pump when I had it apart, it looked great - no scratches or scoring, so I reused it. I wish there was a way to test the lpo isolated from the hpo, it would eliminate a lot of guessing.
When I get it figured out, I'll post it here. Maybe even with pictures, I like posting pictures.

Just out of curiosity, are you showing RPMS while cranking? If the RPM's are not high enough that will prevent it from starting. Just wondering if the starter has been damaged from all of the cranking in attempts to start it. Also when you are cranking are you showing a FPW ( fuel pulse width ) number?

The lpop is separate from the HPOP in that it only requires the lpop to supply oil the HPOP reservoir. Look at the coffee table book for a better explanation.

Yeah, I'd just like to be able to pressure test the low side separately. If there's a big leak in the hpo, it could be making the lop read low, which I think is what's happening. Good 10-15 second crank this morning at +29F, got about 20 lbs of lop and barely made 200 hpo. 20 lbs should be more than enough to run the hpo.
The batteries and starter are brand new, it's cranking like a bitch, I think I remember seeing 238 rpm's... didn't pay much attention to it because it was cranking so fast. I didn't get injector pulse width set up yet on my Scangauge, I'm sure there is none. PCM would not let the ficm fire them at 200 lbs.

And being that it was building 4000 lbs with cool oil just before it quit, I'm thinking a leak instead of the pump. Going to be a few days before I get at it, it's bringing cows home time.

Intall block offs in oil rails and air test high side system.

In your initial post you questioned whether the machine shop could have left out an oil galley plug. Have you checked to see if you have water in your oil? I've seen and heard of those plugs popping out on reman engines. It happened to us once on a 6.4 which is why we use threaded plugs. If you had a runaway, I'd suspect it's probably HPOP related but check your oil if you haven't already.