Navistar Engineering

[mekanik]

I had an International Work-Star with a Maxxfarce 10 in the shop yesterday. The complaint was after driving for a few minutes the check engine light would come on. I scanned it and it had two faults for injection pressure above desired and below desired pressure. My best guess is either the injection pressure sensor or the injection pressure regulator was failing. Since they are both prone to failure and can kill the engine on the road my advice was to replace both.
The pressure sensor is located under the valve cover. To remove the valve cover first remove the intake pipe from the cooler to disconnect the two connectors from the valve cover gasket, remove the wiper arms then the plastic trough below the windshield then the wiper transmission. Then get a box and put all the crap in the cab in the box. Then remove the plastic trim that holds the floor mat on both sides, remove both seats the storage box between the seats the fire extinguisher the throttle pedal the cup holder and the Allison Transmission shifter then roll the floor mat back and remove the plastic cover from the firewall, . You can now see the rear of the engine. Remove the two connectors at the left rear of the valve cover gasket and remove the cover bolts. Now lift the valve cover and tilt it just right and it will come out from the rear into the cab, this usually requires a bit of cursing. There it is the pressure sensor screwed into the side of the high pressure rail at the rear. Replace the sensor. If it had an engine brake I would replace the brake pressure sensor and control valve more $$$ replace the expensive valve cover with the wiring harness built into it $$$ again. six hours later its back together.
The Injection pressure regulator threads into the back of the high pressure pump between the intake manifold and air compressor. Get the special 1 3/8" socket with a slot machined in it to clear the connector and slip it under the copper main air line onto the IPR. Keep a magnet handy for when you drop it. once you get it in place with a 3/8" universal and extension thread it out. Carefully thread the new IPR in without dropping it, its a hydraulic valve and if you drop it it will land valve end first in the dirt. once the new one is in with a universal and extension there is no way to accurately torque it so I gave it my best guess. Next try to get both my Sasquatch size hands in there to plug the new IPR into the engine harness.
Once its all back together when you start it will run rough and miss and clatter for about ten minutes until the air is out of the high pressure system.
7.5 hours to replace a sensor and an actuator test drive the truck. I have always wondered do engineers really hate mechanics.

 

[cuttin edge]

same guy that puts the starter on a nissan under the intake manifold.

 

[stinky64]

They're all sitting around an Ikea coffee table sipping lattes giggling, "wait till they see this nonsense we saved 37 cents on, they're gonna have a schit hemorrhage "

 

[terex herder]

This poem is from an earlier day, but the sentiment is the same.

The Designer
The designer sat at his drafting board
A wealth of knowledge in his head was stored
Like "What can be done on a radial drill
Or a turret lathe or a vertical mill?"
But above all things a knack he had
Of driving gentle machinists mad.
So he mused as he thoughtfully scratched his bean
"Just how can I make this thing hard to machine?"
If I make this perfect body straight
The job had ought to come out first rate
But would be so easy to turn and bore
That it would never make a machinist sore
So I'll put a compound taper there
And a couple of angles to make them swear
And brass would work for this little gear
But its too damned easy to work I fear
So just to make the machinist squeal
I'll make him mill it from tungsten steel
And I'll put these holes that hold the cap
Down underneath where they can't be tapped
Now if they can make this it'll just be luck
Cause it can't be held by dog or chuck
And it can't be planed and it cant be ground
So I feel my design is unusually sound.
And he shouted in glee, "Success at last!
This god*am thing can't even be cast.',

 

[Coaldust]

The Maxfarce has caused so much pain and heartache

 

[Bumpsteer]

same guy that puts the starter on a nissan under the intake manifold.

Cadillac's Northstar had the starter there also, wtf?

Ed

 

[cfherrman]

If I was a mechanic I'd probably refuse to work on them.

 

[Coaldust]

If I was a mechanic I'd probably refuse to work on them.

I purged the fleet of them, as fast as I could. They were an incredible money pit, on the books.

Even, in a revenue shop situation, no way would I recommend anyone work on them. You can’t win. The customer is going to be pissed, either way. They are never “fixed”. It’s a constant trail of sorrow and self destruction.

 

[cfherrman]

Being the cheapest and government buying only the cheapest keeps them in business. They don't work on them they just throw them away.

 

[92U 3406]

I've never viewed Navistar/International as a legitimate manufacturer anyways. Always seemed like they were a subpar product with horrible engineering and designs.

 

[Coaldust]

The dealers always seem to be heavy in the school bus market and thst goes with the gov thing.

 

[cfherrman]

I remember an adept ape video about pulling the egr cooler or something, he couldn't get it out because long bolts were hitting the frame. He's like the same company designed the engine and the chassis and you have it where the bolts can't come out!

 

[Acoals]

Cadillac's Northstar had the starter there also, wtf?

Ed

That was only the beginning of the stupidity on the Northstar . . .

 

[mekanik]

Had another Maxxforce 10 delivered to the shop last week. The engine light and the warning triangle were both on. The Maxxforce 9 and 10 will log codes if the battery connections are in poor condition they were so I cleaned them. I cleared the codes and only one came back. The truck also has a battery disconnect switch which causes a problem with the engine ECM loosing its programming if the keep alive power to the ECM or the battery grounds are disconnected. The ground was being disconnected.
I checked the three temperature sensor readings on the exhaust and they read 32f the exhaust outlet was -495f so the ECM needed to be reflashed. The EGR valve and the DPF differential pressure sensor were not connected and there were no faults for them. What were the engineers thinking? If the battery goes dead or is disconnected for a few weeks the truck has to go to the dealer to be reflashed.

 

[Coaldust]

That’s ridiculous. I recall running into that issue before, but never associated it with the battery disconnect. Which now, makes sense and explains a lot.

 

[Steve Frazier]

Navistar developed such a poor reputation for their brand engine trucks that many of the highway departments around me abandoned them and have bought Freightliners. A sad thing to see after the rock solid reputation of the 466.

The Town I work for has revisited Navistar trucks but they are powered with Cummins engines instead of Navistar.

 

[mekanik]

I believe the Maxxforce 7 is the only international engine that is still in production.
Another terrible engine!

 

[PeterG]

A sad thing to see after the rock solid reputation of the 466.

Although the truck is slow, old, and underpowered, I like my DT466. I had an inline rebuild and it didn't cost too much. Excellent low end torque. Its been a good truck at half the price of a new diesel pick up.