3406E with a "Driver" uprate job

rzucker

Well-known member
This morning I get an angry phone call from a customer, seems his truck is sitting at the ryegrass rest area dripping oil and blowing white smoke... Last September I replaced the head on this truck, it was pressurizing the cooling system something fierce. The machine shop said the head was junk, full of weird little stress cracks.
Anyway I go to look at the truck at the rest area. It's dripping oil from the exhaust joints and the blowby is unbeleiveable. Then I caught it... Resistors on the manifold pressure sensor plug and the fuel temp sensor plug. Those weren't there when I replaced the head, I'm betting hidden away while the head was being done and somebody forgot to hide them today?
Got it towed to the shop and have the resistors stashed in my tool box for the owner to see. Head's not off yet, but I'm sure it's a scored liner and piston.
 

Steve Frazier

Founder
Staff member
I'm not familiar with what's going on, but I'm wondering if the resistors you mention allow it to build more boost than it's designed to?
 

JasonG

Well-known member
They trick the computer into thinking there is more boost.
This causes it to add more fuel.
The danger is overfueling. Sounds like that's what happened.
 

Goodysnap

Well-known member
More power is never as cheap as a $3 resistor. Pay me now or pay me later, doesn't matter. Sad part is when people try to take advantage:badi, lucky you caught it.
 

Truck Shop

Well-known member
Good you caught it. That trick has been around now for a while. Some years back when we had T-800's with C-15's a new driver pulled that trick. The other mechanic
and I watched him leave the yard. It didn't sound right and too much smoke we had dispatch turn him around back to the shop. Gayle the other mechanic zeroed in on
resistors right away. The driver got his walking papers.

Truck Shop
 

rzucker

Well-known member
Good you caught it. That trick has been around now for a while. Some years back when we had T-800's with C-15's a new driver pulled that trick. The other mechanic
and I watched him leave the yard. It didn't sound right and too much smoke we had dispatch turn him around back to the shop. Gayle the other mechanic zeroed in on
resistors right away. The driver got his walking papers.

Truck Shop
Yep. These bozos just want the bragging rights climbing the hills. Most of them aren't old enough to know about the old days when you could crater an engine if you didn't know and understand what you were doing.
Remember sleeving head bolt holes in the older Cummins NTA's? It's funny how the N-14 never needed that if the factory parameters were left alone.
This 3406 would probably still be pulling loads if Doofungus had left it alone. Rant off... Oh, driver in question gets to drive a Cummins Formula 350 for a bit until the engine autopsy is completed. Then I think the axe will fall.
 

JasonG

Well-known member
Yep. These bozos just want the bragging rights climbing the hills. Most of them aren't old enough to know about the old days when you could crater an engine if you didn't know and understand what you were doing.
Remember sleeving head bolt holes in the older Cummins NTA's? It's funny how the N-14 never needed that if the factory parameters were left alone.
This 3406 would probably still be pulling loads if Doofungus had left it alone. Rant off... Oh, driver in question gets to drive a Cummins Formula 350 for a bit until the engine autopsy is completed. Then I think the axe will fall.
Just to tell "both sides of the story" I had a 94 that I resistored the MAP.
Drove it that way for nearly 15 years.
However, I kept my right foot linked to the pyrometer on hills. Just like the old days 😀
 

rzucker

Well-known member
Just to tell "both sides of the story" I had a 94 that I resistored the MAP.
Drove it that way for nearly 15 years.
However, I kept my right foot linked to the pyrometer on hills. Just like the old days ��
I hear you on that, but neither one of us would do that to another man's truck.

Got this one opened up today #2,#3, and #5 are all scored . #2 is the worst, all the way around and very deep. This won't be a repair but a complete inframe.
 

Truck Shop

Well-known member
That will be a few bucks, the head any good? I wonder if the counter bores need to be cut for shims? The last four I did had to have shims.

Truck Shop
 

rzucker

Well-known member
The head went out this morning, we'll see what Sam has to say, So far the block looks perfect. Got a Cat Gold kit coming, so we'll see what the dial indicator has to say when it gets here. Bearings say it was time for an inframe anyways.
 

Truck Shop

Well-known member
That will be a great runner when you get it done. Probably better than the Cat house can do it.:cool:

Truck Shop
 

rzucker

Well-known member
Got the kit this morning, had to JB some pits in the lower liner bore so the O-rings won't get cut, the pits are in the bevel so the O-rings are below the J-B. Block is clean and the mains are in. Hopefully have the liners checked and set tomorrow. Doubt much I'll see the head before Tuesday or Wed. next week, but I'll be ready.
 

rzucker

Well-known member
RZ how is that inframe coming?

Truck Shop
Had a couple of "emergencies" here and there, then it turned out the spacer plate was .003 undersize and the new liners were too high by spec. Should have a standard plate tomorrow and get back at it. The emergencies were from the truck owner, so they cant be too worried. New standard plate should put me right at .005" protrusion. just where I want it.
 

Truck Shop

Well-known member
You know not many people sled gauge the liners. And most don't know you can buy under size and standard spacers for Cat. And .005 is right on the money, perfect seal.:)

Truck Shop
 

rzucker

Well-known member
Just a little update here. Engine went together just fine, removed the resistors too. Had a friend with ET set the trim codes on the new injectors and check the probe timing. This is where things get strange... According to ET there are "Black spots" in the ECM programming that will not communicate with ET. Also according to Cat's arrangement number, it has the wrong turbo. The owner has driven it for a week now and says it's set way too hot for his taste going by the pyro. He's not mad at me the mechanicals are doing just fine. He took it to Cat to see if they can do a reflash to original specs... Nope it's got some "Skunkworks" program with custom passwords.
NOBODY knows where this came from. It's looking like a reflashed reman ECM and the proper turbo are in the works next week.
 

rzucker

Well-known member
Yeah, the truck has had 15 drivers since '06. I did talk to the one that drove the last 4 years, he's an old timer that drove by the pyrometer and said she was a hotrod and drove it like it had an egg on the go pedal. the new guy just ran it hard as it would pull. I'm pretty sure it's going back to the factory parameters this week.
 

Truck Shop

Well-known member
Great glad it's running ok mechanically. Our trucks are set up with only the owner and his son can give the password to reset parameters. When trucks are sold they
have the password cleared. Every now and then a new driver tries his luck.

Truck Shop
 
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