Spending some time with the t444e

[quickgrits]

We got in a rush with our conversion before leaving on a two month 7500 mi trip this summer. I knew there were some mechanical issues that I didn't understand so I intended to look over the engine (and begin to learn something about it - I'm new to "E" diesels) before we left. We ran out of time though and decided to just hope for the best and go. We got lucky and it worked out fine.

So we made it back and had a fantastic time and now we're going to finish up the conversion and also look into this engine.

I figured that I could relate the problems we're having and my ideas of how to get at them and maybe get some advice if anyone is so inclined.


The engine has always cranked right up in cold or hot weather. It doesn't smoke noticeably but there is a bit of oil splattered on the back of the bus after 8000 miles. It used about 5 quarts of oil in that time as well.

Here's the general round up of issues and symptoms.

- Feels sluggish:

This is the only bus I've ever driven but it sure seems slow. It took us wherever we wanted to go but we did have to downshift to first on one occasion. I was relieved to see a very few trucks on our trip that were slower than us up grades. but I suspect this thing should move a little better.


-Low boost pressure:

I have a scanguage d and with the load rating at 100% the boost pressure never gets above 11 psi (according to the scanguage)

A few days ago I finally pressure tested the turbo pressure side and found a significant leak at the turbo outlet. replaced the o-ring there and tightened some things to stop other smaller leaks. All the piping seems tight now though the system still wouldn't hold pressure long because there was a leak inside the engine (could hear it at the oil filler). I assumed this is to be expected with air slipping past intake valves and rings.

Drove it a bit and the maximum boost pressure has increased by 1 psi or so. Maybe it felt a little more powerful.

-Occasional 333 code:

icp above/below desired level.
This has happened maybe 3 times in the 8000 or so miles we've driven the bus. I don't notice any difference in the running of the engine when this happens and the engine warn light is on.

cadillackid a while back suggested that I compare ipr duty cycle with the icp reading. I was able to get icp working on the scanguage but it constantly jumps all over the place from maybe 9 to 300 psi at idle. If my understanding is correct the engine wouldn't be running if the icp was really jumping around so much. The scangauge lady told me that ipr duty cycle was not available for this engine.

I checked the wiring to the icp and ipr so far as i could with a multi meter according to the instructions in the diagnostic manual. it checked out except for one of the wires going to the ipr reading .33v instead of the <.25v it's supposed to with the ignition on. (Maybe that's not enough to worry about?)

So according to my rudimentary understanding of this thing here are the possible problems that I think I should look in to.

-Bad IPR? I think it can be cleaned and re-built?

-Bad ICP sensor? Maybe I should just replace it though it's shiny and looks new.

Maybe I should take the valve covers off and measure the compression to get an idea of the condition of the important parts. While I'm at it I could look for
-High pressure oil leakage at the injectors and replace the o-rings if necessary.

Is there anything else I should be testing/ looking at?

I'm going to do some little easy projects for a day or two before coming up with a plan and getting into this mechanical stuff.

[cadillackid]

first off ! excellent that your road trip went well!!!

the 444E is not a fast engine, esp if you have the 175 HP variant.. or the 190 in a full size bus.. I see yours is a 3000.. is that a flat nose RE 11 or 12 row?

if you have the 190 HP variant of the 444E you will get 14-16 lbs of boost at full throttle and 2500-2600 RPM.. if your RPM is below that you womnt get that high of boost.. which HP stamp is marked on your valve cover?

DONT overfill the oil.. it WILL blow it out of the draft tube.. and its EASY to overfill the oil as you pour it in the valve cover so it takes a little while for it to settle down to the pan.. so you pour some and check it and still looks low ..you need to give it a few minutes after you pour it to re-check it..

the ICP jumps all over that is normal as the engine demand moves a bit.. not sure why they say the duty cyclke isnt available for that engine.. i read it all the time on mine..

.33 volt vs .25.. thats .08 differenct or close to 20%.. thats a big deviation.. enough that can cause the WARN light to come on.. the engine will still operate even when the code is active.. if the ECM thinks that the ICP is not responding at all then it will set another code, disable reading the ICP and run at a set default value of pushing the IPR to a certain state.. but an IPR reading that far off can mean an issue.. however if the ICP is reading it back correctly then it just means the ECM must command it differently.. however if it goes to default mode you will for sure have less boost than if its operating normal.. or if the ICP is lying to the ECM then it may not be pushing enough HPOP pressure.. only way to know is run the computer, read it and a real gauge on the HPOP at the sdame time.

some people just automatically replace the ICP and the IPR when they buy a used 444E..

if you get your 444E hot, it will begin to de-rate power at 216 degrees f coolant or oil temperature.. high oil temperatures are caused by running flat out RPM in hot weather.. usually the coolant temp is up there too..

also if yours has an EBPV make sure htat is working OK.. thats a known issue to cause low power.. as it is blocking part of the exhaust (to warm the engine up in cold weather).. if that doesnt function correctly then you have excessive exhaust backpressure and less flow into the turbo turbine.. which results in lost boost / power..

the 444E is a V-8 diesel.. while it is on paper rated at its peak torwue at a low RPM in the mid teens.. and peak HP at 2300... unlike an inline 6 diesel that likes to run at its peak Torque RPM, the 444E feels most powerful when its RPMs are above 2200 or so... this is **NOT** where you want to cruise out.. (my 444E loves to highway cruise at 1600-1800 RPM(65 MPH - 1550 RPM(6th), and 1750 or so (5th)).. the high RPMs are what it likes for making boost and climbing hills or pulling into traffic... so when i climb a hill I pull it down to 4th (2450 RPM at 65).. Ill see my boost rise up to over 15 if I get it up to 2600 or so.. max is 2700 on mine,

-Christopher

[quickgrits]

Hey! thanks for the reply!

This is a 190 hp engine in a 12 row RE with an at545. I was hoping for a better drivetrain but we needed to get going with the conversion and went for this one. I think now that it's not so bad so long as you're not in a hurry and you don't mind having to be careful with it and you don't know any better! We're just happy that it's taken us wherever we've wanted to go so far.

It's limited to 60 mph and It wouldn't want to go any faster.

The engine speed tops out around 26 or 2700 rpm. At that speed with the throttle floored the boost will read 10 or 11 psi.

We ended up forming a strategy for getting up hills without getting hot. We'd downshift on a long hill to keep the engine loading below 100% and then we'd modulate the throttle to keep the rpms between 2200- 2500 or so. It felt good to see the temperature drop while climbing - slowly. and we used the heater.


I don't think I've ever overfilled the oil and haven't seen much drippage from the draft tube.


The EBPV is working correctly

I think I read somewhere that the icp at idle should be around 400? I don't believe I saw it get nearly that high I'll check it again tomorrow.

I'll attach a page from the diagnostic manual that covers checking the wiring to and from the IPR. I've written the actual measurements I took. I measured .33v from B to ground and the manual says: "If greater than .25v, signal wire is shorted to V Ref. or battery." I think V Ref. is the other wire which is 12v. It's hard for me to see how a short to something at 12v could show up as only .33v. Not sure how to start but I guess I should probably look into this first before I get into anything else.

Christopher, you have a scangauge d that will read ipr duty cycle? I emailed my PID's to scangauge and they sent back some "x-gauges" but not that one. And yeah, they told me it wasn't available for that engine.

[cadillackid]

im using the navistar Servicemaxx software which shows me the various cycles.. the data is all coming from the J1708 port so its requestable.. perhaps the Scangauge D wont display on-request PID's?

at around 2500 RPM or so you should be getting more than 10-11 on boost. I also have the 190, I'll try and take a reading when I run it later today.. I can run servicemaxx and see what my duty cycles are too.. although the screen data is small so its not easy to take a video of while driving..

you have the manual pages which is cool.. make sure its for your year. the procedures are different for 1997+ engines vs 1996 and earlier..

im not familiar enough with the RE versions of these engines to know how the turbo cooler vs radiator is sized and what type of fan clutch you have.. if you are getting hot id expect your fan to be on. of course if you are modulating down the throttle you are of course not going to get the boost up to 15-16.

the max RPM is 2600-2700 so thats normal when you get there to feel the power loss as the computer backs off on the fueling when it reaches those RPMs. (or if the cokmputer speed limiter is set at 60 or below you'll see the same .. the fueling is reduced.).

-Christopher