1083A1 doesn’t run longer than 45-60 seconds

[AKAustria]

Happy Labor Day weekend!

I have an issue that seems so simple, but I can not figure it out.
My 1083A1 truck has been sitting for some time, but it always ran and I drive it on the road, registered it, loved it.
Last spring, it didn’t want to start anymore or died right away.
I traced it to a leaking fuel water separator, replaced filter and gaskets… it does start now after cranking for about 10 sec and stays running. But only for about a minute at the most.
It doesn’t really take throttle happily and no matter what I do, it stalls after 45-60 seconds.
any ideas would be greatly appreciated.
My thoughts are… it can’t be too complicated since it was a good running truck before, but I am still completely new to these amazing machines.
Thanks everybody!!

 

[aw113sgte]

Happy Labor Day weekend!

I have an issue that seems so simple, but I can not figure it out.
My 1083A1 truck has been sitting for some time, but it always ran and I drive it on the road, registered it, loved it.
Last spring, it didn’t want to start anymore or died right away.
I traced it to a leaking fuel water separator, replaced filter and gaskets… it does start now after cranking for about 10 sec and stays running. But only for about a minute at the most.
It doesn’t really take throttle happily and no matter what I do, it stalls after 45-60 seconds.
any ideas would be greatly appreciated.
My thoughts are… it can’t be too complicated since it was a good running truck before, but I am still completely new to these amazing machines.
Thanks everybody!!

I would check for a clogged tank vent.

 

[AKAustria]

Okay. Definitley will do that today as soon as I get home.
Thank you!!

 

[GeneralDisorder]

Also the fuel lines on these are known to rot out and leak. My 2008 already had a leaking hose and the others were BAD with dry rotting and cracks. The outer rubber just falls off in chunks. Run your hand over them and if it comes off looking like black coal dust the lines are shot. Sometimes the leak will not necessarily be super obvious on the lift side of the system since it is sucking and there's no pressure present - it will suck air like there's a hole in your drinking straw.

When you first start the engine it's on cold enrichment (black smoke if it's cold enough out, or when you accelerate the engine, etc) - as the engine leans out to normal operating fueling it sounds like it's not getting enough and dying out.

 

[Ronmar]

There is a test port on the fuel line between the lift pump and the fuel filter mounted to the side of the engine. Connect a snubbed/dampened 0-100PSI gauge there to measure baseline fuel pressure. Should have 20-25 at idle ramping up to 60PSI by peak torque RPM. any dips in that pressure are probably air pockets being admitted somewhere between tank and lift pump…

Leaks look like this on a gauge…

 

[MatthewWBailey]

There is a test port on the fuel line between the lift pump and the fuel filter mounted to the side of the engine. Connect a snubbed/dampened 0-100PSI gauge there to measure baseline fuel pressure. Should have 20-25 at idle ramping up to 60PSI by peak torque RPM. any dips in that pressure are probably air pockets being admitted somewhere between tank and lift pump…

Leaks look like this on a gauge…

How's that cruise control lever work. I don't have that.

 

[Keith Knight]

Replace fuel filter as well.

 

[AKAustria]

I would check for a clogged tank vent.

Can the air vent for the tank be easily identified?
I would agree that this is the most logical explanation.
first thing I do when getting home is to open the tank cap and see what happens!!!

 

[Ronmar]

Can the air vent for the tank be easily identified?
I would agree that this is the most logical explanation.
first thing I do when getting home is to open the tank cap and see what happens!!!

Three hoses off the top of the tank, supply, return, both are JIC6 fittings. The vent port is farther forward, smaller and on a hose barb fitting…

 

[Ronmar]

How's that cruise control lever work. I don't have that.

Don’t have the pneumatic canceling cylinder hooked up to the brakes yet, so its a little sketch…

 

[AKAustria]

Three hoses off the top of the tank, supply, return, both are JIC6 fittings. The vent port is farther forward, smaller and on a hose barb fitting…

Great! I really appreciate it. Can’t wait to test it

 

[Ronmar]

Great! I really appreciate it. Can’t wait to test it

You should still know how to hook up a primary gauge. Good houses have good foundations and baseline fuel pressure is the foundation of this process. Often overlooked, but a fairly common source of problems. Unit injectors rely upon it and can be damaged if it is not right.

 

[Lostchain]

Can the air vent for the tank be easily identified?
I would agree that this is the most logical explanation.
first thing I do when getting home is to open the tank cap and see what happens!!!

Clogged fuel tank vent M1078A1

Hello, I noticed when fueling my LMTV there was a lot of hissing when opening the fuel cap. I was also having a very subtle idle surging issue and while reading posts I saw mentioned a clogged vent several times. I did a little digging on the forums and couldn't find any pictures or good...

www.steelsoldiers.com

 

[AKAustria]

So I ended up removing the fuel cap, cranked… no start. Batteries are very weak ( I have currently only 2 hooked up), so I will again tomorrow.
I did lift the cab and prime the fuel/water separator for good measures. I thought it can’t hurt.
Either way, no start unfortunately