DT466E Injector O-rings and Cups

rensch26 · 08-17-2017, 01:18 PM

I have a 1999 AmTran FE with a DT466E in it. The bus was experiencing some sputtering when the bus was under a load like accelerating through the gears from a complete stop or driving uphill. The problem gets worse as the engine warms up and the oil thins out. I hooked 100 psi of air up to the high pressure oil rail (per the International trouble shooting manual) and saw bubbles coming from the injectors. This would mean that I'm losing fuel injection pressure and is contributing to my engine sputtering when under a load.

I pulled the injectors out and replaced all of the o-rings and cleaned the injector cups out with rags and degreaser. I sucked the oil and fuel out of the cylinders and reinstalled the injectors and torqued them back down. I hooked the compressed air back up to the oil rail and am still getting some air bubbling past the o-rings. Not as much as before but I don't believe I should be getting any air past according to the manual. I took the bus out for a long drive to work air bubbles out of the system and the bus was behaving just as it did before. Sputtering while driving up hills or while shifting through the gears from a dead stop.

I will take the injectors back out and try doing an even better job of cleaning the injector cups and see if that helps the o-rings seal better. If that doesn't fix the air leak past the injector o-rings my question is is it possible for injector cups to distort? The bus has 211k miles on it. Maybe it's not a bad idea for me to go ahead and put new injector cups in it but I'd like to understand if others have had this problem as well and what they did to fix it.

cadillackid · 08-17-2017, 01:30 PM

I know there was a problem with the 7.3's that the injector cups could crack.., the 466E uses a very similar setup, are you setting any codes in regards to the ICP or IPR? it almost sounds like the injection control oil pressure is low.. the rail fuel pressure is usually 47-65 PSI depending on the engine variant..

where are you seeing the bubbles at? coming up out of the head into the valve cover area? if thats the case.. are you gaining oil level as you drive? or does the oil smell like fuel?

-Christopher

rensch26 · 08-17-2017, 01:39 PM

I haven't taken it to anyone yet to get the computer scanned for any codes yet. I'd love to do it myself but I'm not sure what I'd need to buy in order to do so. I did unplug the ICP sensor and it didn't seem to make it run any better so I believe the ICP is ok. I do think that my IPR valve could be contributing to my lack of injection pressure but I'm trying to eliminate this problem first and see if my sputtering continues.

Yes, the air bubbles are escaping past the top o-ring of the fuel injector which means hot, thin oil is escaping past that o-ring into my valve cover and draining back into the pan like the rest of the oil under the valve cover.

I recently changed my oil and sent a sample to blackstone labs in Fort Wayne, IN and the report came back in really good shape. No fuel or coolant was found in the oil. So the injector cups are not cracked and are still sealing off the coolant flowing through the head. So I'm just wondering if maybe I need to do a better job of cleaning the injector cups (maybe buy an actual brush designed for the job) or I'm wondering if it's possible for the cups themselves to distort?

dmattarn · 08-17-2017, 01:43 PM

When I had issues with my '99 IH/Amtran FE I took it to the international dealer and they scanned my codes for free.

Could be a very small micro crack in the injectors or cups

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rensch26 · 08-17-2017, 01:47 PM

Quote:

Originally Posted by dmattarn

When I had issues with my '99 IH/Amtran FE I took it to the international dealer and they scanned my codes for free.

Could be a very small micro crack in the injectors or cups

Sent from my SM-G930V using Tapatalk

Ok, thank you. I'll try to take it to my nearest dealership soon and see if they'll scan it for me.

I don't believe there is a crack in the cups. That would mean I'd be getting oil or fuel in my coolant (both the oil and fuel operate at a higher pressure than the cooling system) and that hasn't been the case yet.

cadillackid · 08-17-2017, 01:52 PM

oh Ok.. I was thinking you were pressurizing the fuel rail and not the Injection oil rail.

if the WARN ENGINE light is on while its running there are codes set. you should be able to turn the key on (but dont start) and then press and release the diagnostics button thats next to the round connector under the dash.. this should cause the WARN light to flash you out the codes in sequence. then we can look then up.. they are 3 digit codes.. so you would see say flash-flash pause flash-flash pause flash would be '221' then it pauses longer and flashes the next code out.

-Christopher

rensch26 · 08-17-2017, 01:56 PM

Ah yes, pressurizing the oil rail. I measured my fuel pressure off of the fuel filter housing and it was within spec so I moved on to the oil system.

The Warn Engine light was only on while I had the ICP sensor disconnected. Thank you for the information about the flashing of the codes. I was unaware that you could do that.

meteoricide · 08-18-2017, 05:22 AM

Quote:

Originally Posted by rensch26

Ah yes, pressurizing the oil rail. I measured my fuel pressure off of the fuel filter housing and it was within spec so I moved on to the oil system.

The Warn Engine light was only on while I had the ICP sensor disconnected. Thank you for the information about the flashing of the codes. I was unaware that you could do that.

That switch is momentary so press and hold while turning key to on then release it. Get ready to count codes/ copy down. Active codes will come first, followed by inactive. Three flashes together means no more codes or if thats all you see there are none in history either. This was my experience

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rensch26 · 08-18-2017, 08:21 AM

Quote:

Originally Posted by meteoricide

That switch is momentary so press and hold while turning key to on then release it. Get ready to count codes/ copy down. Active codes will come first, followed by inactive. Three flashes together means no more codes or if thats all you see there are none in history either. This was my experience

Sent from my iPhone using Tapatalk

Awesome. Thanks for that bit of information. I'll definitely do that.

rensch26 · 08-18-2017, 10:12 AM

I got to thinking about my problem a bit more. I realized that the injector cups probably don't have anything to do with my oil leaking past the top o-ring on the injector. The injector cups are very far down in the injector bores and do not come close to the high pressure oil being delivered to the injector. The injector cups simply allow heat to transfer from the injector to the coolant system.

Perhaps the injector bore itself is dirty and needs to be cleaned better in order for my o-rings (specifically the two o-rings towards the top of the injector that are responsible for sealing in the high pressure oil) to seal. I'm also wondering if the injectors maybe just need to be torqued down a little more. The torque spec according to the engine manual is only 120 in-lbs.

cadillackid · 08-18-2017, 12:02 PM

makes sense. I also wonder if all the o-rings for the various injector revisions are the same... or is it possible that you got the wrong O-rings..

something that stands out is that you dont get a WARN light even when you are on the power.. if ther ECM commands the IPR to go to a certain pressure.. it then reads the ICP to make sure that the actual is there.. if the actual and commanded are off too far i thought it would set a code and trip the lamp.
it sounds like you have the navistar service manuals.. but if you dont have the electronic service manual I can look it up in mine if you want.

the oil leak would likely cause the IPR to command at a higher percentage than it otherwise might... also oil does act as a sealant in some cases.. so where you see air bubbles it might be a minuscule oil leak..

when you checked the rail Fuel pressure did you do it under load or just at idle? I dont think there is a fuel pressure sensor, so if the rail fuel pressure was low it wouldnt set a code but definitely could cause the issues you are epxeriencing.

just thinking out loud here.

-Christopher

rensch26 · 08-18-2017, 12:13 PM

Yeah I'm on board with that thought as well. I find it strange that I'm not getting a warn engine light while driving. I would think if I stayed on the throttle up a hill and the engine continued to sputter the ICP would eventually detect a decaying oil pressure in the rail and just command the IPR to increase oil pressure from the HPOP.

Yes, I have a lot of the engine manuals and trouble shooting guides. I used to work for Navistar and still have some friends there that were able to get me .pdf versions of all the manuals.

I was wondering that myself. The air leak seemed to improve slightly after I replaced the injector o-rings. The trouble shooting guide is what instructed me to use 100 psi of air but it doesn't say whether I should see zero air bubbles or only a few. I would assume I shouldn't see any air escaping.
I believe I received the correct o-rings as I had to provide the engine serial number to the dealership and I believe the injectors for the 7.3 and the DT466 were the same design from ~96-04 before the design was changed.

When I checked fuel pressure I did it off of the schrader valve and it was around 45-65 psi according to my gauge throughout the rpm range.

I'm wondering if the shoulder bolts that hold the injectors down can stretch a little bit over time or perhaps my torque wrench isn't very accurate.

cadillackid · 08-18-2017, 12:19 PM

i would think it should be pretty sealed at 100 PSI since the HPOP pressure can be over 1000 when the engine is under load.. i suppose the ICP sensor could be "plasteauing" and reading a higher pressure than whats actually in the rail..

fuel pressure at Loaded RPM or unloaded? ie if you no-load punch the pedal (in neutral) im assuming the engine runs up to the rev limiter without issue? or does it sputter then too?

if it doesnt, then what about loaded .. park brake on foot brake on run it up a bit.. (dont want to ruin the transmission but you can load it for a few seconds at a time to some extent and see what the pressures do)...

worst case im only 3 hours away and i own the Nexiq device and have Navkal and servicemaxx. (I dont have the DLB software).

-Christopher

rensch26 · 08-18-2017, 12:28 PM

Yeah exactly, I would think 100 psi of air would be relatively easy for the o-rings to hold back. The oil pressure on these engines gets well over 3000 psi when under a load.

I measured the fuel pressure under no load. Just parked in neutral. The engine runs great when you're not under a load and the computer isn't demanding high injection pressure. I can run it up the governor all day long on flat ground with no problems.

I will try measuring fuel pressure when the engine is under a load. I've also rigged up a "T" to tap into the oil being delivered from the HPOP to the rail and measure the oil pressure with a gauge. I'd like to take the doghouse off and drive it around with these gauges in place and have a family member watch them but the only issue is I have to secure the ECM somewhere because it has to be taken off to access the elbow where the oil is delivered to the rail.

We may actually be going to the Columbus area this fall to go atv riding so I may have to take you up on your offer!

rensch26 · 10-07-2017, 04:30 PM

Just wanted to come back and update this post. I hooked up a fuel pressure gauge to the engine and it was dipping just below 40 psi when under a load. The minimum spec for this engine is 45 psi so I replaced the fuel pressure regulator on the back of the fuel supply rail and that cured that problem. Fuel pressure sits at 60 psi just like it is supposed to.

This didn't cure my sputtering problem though so I pulled the injectors out and had a diesel shop test them. They were letting quite a bit of high pressure oil flow right through them and under a load they were flowing 25-30% less fuel than they were supposed to. After 211k miles and 11k hours the injectors had finally failed.

Had the shop order up a brand new set of "BJ" code injectors from Alliant Power. The original injectors were "BG" code but they have been discontinued and the BJ injectors serve as their replacement.

Got the injectors installed last night and took it for a spin. As far as I can tell the sputtering seems to have been fixed! The engine seems to be running a bit smoother and quieter. We will be taking the bus to West Virginia next weekend to ride ATVs so I will report back on how it ran and what kind of fuel mileage we got.

Rusty · 10-07-2017, 04:40 PM

Quote:

Originally Posted by rensch26

Got the injectors installed last night and took it for a spin. As far as I can tell the sputtering seems to have been fixed! The engine seems to be running a bit smoother and quieter. We will be taking the bus to West Virginia next weekend to ride ATVs so I will report back on how it ran and what kind of fuel mileage we got.

Nice fix! If you don't mind, what did a set of squirters cost?

rensch26 · 10-07-2017, 04:48 PM

Quote:

Originally Posted by Rusty

Nice fix! If you don't mind, what did a set of squirters cost?

They were $279 apiece. Got them from Dave's Diesel in Angola, IN. Spoke to a man named Rick. Very knowledgeable about the HEUI engines.

cadillackid · 10-07-2017, 06:44 PM

did you go brand new injectors or Remans? and is there a reason to go either? I dhould call them as ive been considering swapping injecotrs on my 444E..
-Christopher

rensch26 · 10-07-2017, 08:21 PM

I went with what I was told were brand new injectors but I'm not positive they are. I say that for two reasons. One, $279 seems awfully cheap to me for a brand new injector. Swamps Diesel sells re-manufactured DT466E injectors for ~$315. And two, when I called my local International dealer to get a quote for new injectors they only gave me a quote for re-manufactured injectors. Didn't even give me an option for brand new ones.

Rick at Dave's Diesel told me that CAT still has a contract with Alliant Power so I'm wondering if you can still get brand new injectors for CAT HEUI engines and not International? Not sure that would even make sense. Either way he swore the ones I was buying were brand new.

Given a choice I would always go with brand new injectors, personally. Companies such as Swamps and others probably do a pretty good job of rebuilding the injectors but new is new. The OEM is more trustworthy in my opinion. If your HEUI injectors have ~200k miles on them it's just a matter of time before they start to go. Especially in an application like a school bus that spent a lot of time idling and racked those 200k miles up the hard way.

cadillackid · 10-08-2017, 09:21 AM

I have about 160k on mine but i have close to 9000 hours.. the last 16k is probably the most that bus ever saw in a year and thats all my driving.. only reason i even think about it is beause i do drive my bus all over creation... 1000 mile leg to a road trip is fairly common for me... i drive my school busses more than most people run their daily cars in a year..

whats interesting is I looked up alliant injectors online and they state "brand new" but yet there is a core charge.. so either they sell the cores to some of those companies doing the cheap $159 Remans or these are actually Reman injectors..

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