How similar is DT466 HP Oil system to 6L PSD?

Hi all, Found myself working on a 2007 4300 with a Dt466 powerplant. I typically work on smaller diesel trucks and automobiles, quite familiar with the 6L PSD. However I don’t often work on class 8 vehicles and lack some of the tools that would help- But I agreed to look this over for a friend who has just spent well into five figures elsewhere and is still left with a poorly running truck.

Starting point- Clients truck is a battle to start, requiring priming and lots of cranking to get it going. Once it runs, It will run good for a minute or less then develops a nasty rolling idle. Applying some throttle will ease it up.

Looked over documents from the work they had done, Shop recommended changing injector O-rings, Then Injectors, then HP pump. They replaced the o-rings which allegedly made no improvement, they then billed to install a set of AP injectors. I guess they called it good there, and the HP Pump was never changed.

I found it strange how there is no mention of replacing or even inspecting the IPR/ICP, as I know in a 6L PSD this is one of the first things I’d check.. The IPR appears to be somewhat recently changed, Although there seems to be no paper trail for who did it, or when.

The truck had fuel leaks all over from the primer lines assembly, and eventually found a crack in the fuel filter housing. I knew this was enough to cause priming issues and would have to be fixed, I was hopeful- but wasn’t so convinced it’s entirely to blame for the rough running. So I started by addressing this, The truck now has a Fass pump providing 70 Psi of air-free, leak-free, fueling direct to the rail. So I’ve ruled out low-pressure fueling issues, however the truck is still very long and hard starting without a shot of QuickStart. Once running, It still does the rolling idle.

This brought me back to the ICP/IPR. My scan tools are all Obd2 and don’t work with class 8 vehicles, which sucks.. But I figured I’d go probe the ICP sensor manually and see what kind of voltage I’m getting. I found a solid 5V koeo on the reference voltage wire, However I was surprised to find 1.6V koeo on the signal wire, Bumping up quickly to 2.6V while cranking. Without a scan tool, I’m not entirely sure what pressures that should correspond to. But on the 6L engines (That seem quite similar at a glance) that would be severely out of spec..? I was thinking I’m going to replace the ICP, and the Valve cover gasket/Harness at the same time. The back of this valve cover, including the harnesses are a total mess of oil.

But I figured I’d due diligence, and minimize assumptions that could be easy to make. I know just because these parts look similar to others I’m familiar with doesn’t mean they operate identically, Or they might.. So wanted to ask people with more experience on these Dt466 engines if it seems like I’m on the right path, or if there’s other information or things I should check on this that I may be missing. Is 1.6V koeo actually normal on the International?

 

Thanks for the reply- That would be super appreciated! Working with limited tools and data really sucks, and Im not much for just firing the parts cannon off at issues. Hopefully that can get me a little further ahead. The last 8 are “7H434628”

 

Well, I had some time to mess with it a little today. While probing the Icp the other day, I noticed the back of the engine was all covered in oil, including the icp and injector plugs. So I figured I’ll change the gasket aswell if I’m getting in there.

I picked up a new valve cover gasket and a new icp. Before starting to take anything apart I checked the icp signal volts again, 1.8V koeo today. I plugged the new icp into the gasket, And plugged the harness side connector into it- Koeo this one reads 0.17V. Swapped back and forth, probed again and got the same consistent results.

So I figured I’ll get it apart and change it out. 0.17V seems like a more reasonable value so I think it’s safe to say the old icp is acting up. It took me a while to figure out how to get everything apart having not worked on one of these before, but managed to get the valve cover removed.

Unfortunately found some damage on the back of the valve cover where it appears someone pried on it and displaced the metal, cutting into the gasket and explaining some of the oil leakage. Planning to get that straightened out tomorrow somehow and start getting it back together. Will follow up then, but already feeling pretty confident it will work out and have this truck running much better based on those tests.

 

Thanks a ton, Looks just like what I’m working on and seems to be plenty of good info here! Will definitely be skimming through this and seeing what I can find.

In the mean time, I forgot to mention this yesterday but when I removed the valve cover I noticed some strange “damage” on the oil rail at cylinder 1. I don’t think this is actually causing a problem right now, But I’ve been a bit confused about what I’m looking at here. Is this a normal thing to observe? Does this indicate anything important? Seems like four very randomly spaced divots in the oil rail head, all about the same shape and depth however. Only located above cylinder 1, as viewed in photo.