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Detroit 12.7L Engine Low Power

631G

Senior Member
Joined
Apr 27, 2008
Messages
336
Location
Georgia
Occupation
Civil Superintendent
We have a 01 Freightliner with a Detroit 12.7L series 60 engine in it that has suddenly lost all its power. The day before the issue started the truck ran great. It pulled one of our heavier pieces that we move ourselves, a Komatsu PC360, and was fine. Our driver comes in the next day and heads out only to find that the truck has lost all its power to the point that it struggles to get up to 45MPH unloaded. There is no smoke from the exhaust pipes, cranks easily, filters have all been replaced, drained the tanks when we replaced the filters (all good there) and there are no check engine lights lit up. I am at a loss here.

We are going to try putting a new fuel pump on it today and see what happens there because that's how it seems to be acting (loss of fuel). Could this be an electrical issue? We do have a battery disconnect that we use at night to keep the batteries hot when it sits for a while. Any thoughts on where to start are appreciated.

Truck Info:
2001 FLD120
Serial #: 1FUJAHCG41PF95559
 

James Sorochan

Senior Member
Joined
Aug 1, 2020
Messages
491
Location
Lethbridge county, Alberta, Canada
Occupation
x-water & sewer construction Now farmer.
I blew my air intake clamp on my 2001 Dodge 3500 coming up a hill pulling a heavy trailer. Lost my turbo boost. Lucky I was only 5 minutes from home because I was down probably what felt like 60% of normal power.
 

mekanik

Senior Member
Joined
Aug 20, 2015
Messages
944
Location
Canada's Northwest
There is a 1" hose that goes from the intake manifold to the compressor inlet.
I have seen a few of them split. Take it off and inspect it. They fail on the
side facing the engine from the heat I suspect.
 

631G

Senior Member
Joined
Apr 27, 2008
Messages
336
Location
Georgia
Occupation
Civil Superintendent
I have an independent mechanic headed out to look into the turbo issue. We’ll check out these other excellent suggestions. Thank you for the pointers to look for. We’ll keep you updated as we get closer to the answer.
 

631G

Senior Member
Joined
Apr 27, 2008
Messages
336
Location
Georgia
Occupation
Civil Superintendent
UPDATE: The problem was the charge air cooler. It had failed and was checked out at a local radiator rebuild shop. Put a new one on the motor runs fine but we do have a check engine light on that was not on previously so we on to diagnosing that issue next.... Good times.
 

Steve Frazier

Founder
Staff member
Joined
Oct 30, 2003
Messages
6,599
Location
LaGrangeville, N.Y.
Back when I was green in the seat, I was hauling gravel in a Mack DM600 10 wheel dump. Going down the highway I heard a big BANG under the hood followed by what sounded like a huge hair dryer with a tremendous loss in power. I pulled over and opened the hood and immediately saw a 50¢ hose clamp blown apart and dangling from the intercooler hose. It's amazing how flat these things get without the charge air!
 
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