M923-NHC 250 Cummins-Lots of white smoke-Won't Start

[mpuvdd]

Hey guys,

I recently finished up installing new injectors and replacing a blown head gasket on this Cummins NHC 250. After bleeding the fuel system and cranking it over, white smoke bellowed from the exhaust but it doesn't seem to want to fire.

Could it be that I still have air in the fuel lines and need to try a different approach to bleeding the system? To bleed it I simply cracked the valve under the primer pump, pumped until no air came out, closed the valve and that was it.

Thanks for the support,

Seth

 

[swbradley1]

You need to read the manuals for the truck and the engine. Bleeding a 250 is a little more involved than the valve under the primer pump.

While the engine is cranking you can shoot Ether into the air cleaner mushroom and see if it starts and runs a few seconds.

Don't spray it in without the engine cranking, if you spray it and then crank the engine you run the risk of most of the Ether hitting one cylinder and it won't end well.

 

[mpuvdd]

Update: I found that my fuel filter bowl was only half full of fuel this morning. Somehow I got air into the fuel filter. Is there a transfer pump in the tank that is supposed to kick in on the early model M923's?

After looking through all of the manuals (TM 9-2320-272-24-1,2,3,4) for my M923, I could only find instructions on how to prime the fuel system on an A2/late model truck. Anybody know where to find or want to provide information on how to "prime fuel system" on an early model with a NHC 250? Thank you

 

[Scar59]

No intank pressure pump on the early M939/A1 trucks. Engine suction feeds, Fill the filter bowl as full as you can and use the hand primer pump to pressurize the fuel manifold. While cranking the engine give it a good hot of ether. like Steve says " spray while cranking" may take a coule tries.

 

[elkhtr]

Hi,
TM 9-2320-272-10
Section 3-28
Page 378 of the dowloadable pdf file.
Pump the living tweedle out of it, your gonna have to.

 

[Floridianson]

I myself am not a big fan of filling the canister before install but yes it can be done. I have changed some just useing the primer but soon learned that is a pain. We have had people say to pressureize the fuel tank. Someone had a vaccum pump and took off the line at the PT and sucked the fuel till the system was full. Some have even just cranked the motor over enough but it can drain the battries. Since I do more than one truck a year I have a 12 volt electric selfpriming pump and fitting that goes on the end of the fuel line when I drop it off at the PT and fill the system in 30 seconds. With the older series the pump was more for the cold start system. Seems like the newer series they should have put a hand pump with a bigger bore that can realy move some fuel.

 

[Jeepsinker]

You need to put your state in your location. It's in the rules. It is even more helpful if you put your town too.

 

[73m819]

If everything is tight, the priming hand pump works great, make sure the square washer under the can retaining bolt IS set in the recess on top of the mounting bracket, if the square washer is offset, it WILL NOT seal the o-ring, also MAKE SURE that BOTH petcocks ARE free of dirt and tight. I just changed the fuel filter on a 931a1, hand primed, It started right up, you should NEVER need either to start a engine after a fuel filter change if you did it correctly.

 

[EMD567]

It's only 3000 stokes on my M814 to fill the fuel filter, and prime the IP............