How do I get a 6BT Cummins started after it has been sitting for a while?

[Lonesome7.3]

I have a 5.9 12 valve Cummins in a Dodge that was converted to a military aircraft tug. Everything from the cab up is a standard non military based truck. When I got the truck it ran but had old fuel in it. That caused the truck to shut down and not restart two years ago. Well, I have cleaned the fuel system now and replaced the internally rusted fuel filter. I have new fuel in it and I know it is getting to the fuel pump. I cracked open the injector lines and they are getting fuel as well. The engine will fire on starting fluid but will not stay running. What else do I have to do?

 

[marblecrusher]

So your getting nothing but fuel no air out of the injectors? How many and what number injectors are you cracking open? Injectors could be nasty and clogged from crap fuel or it could be airlocked really good. Try cracking injectors 1,3, and 4 till you get nothing but fuel then close them if it doesnt start im betting a weak p pump or some nasty injectors.

-Jordan-

 

[Lonesome7.3]

I cracked open I think one and four. I did nto think to crack them all open in any kind of order. Thanks!

 

[rebel_horseman]

The engine that he's referring to does NOT have a P-pump on it. B5.9 engines before '94 had the internally lubricated rotary VE pump (which is a better pump for towing and torque IMO).

Lonesome, if you have access to one, you may want to try to install a fuel pressure gauge to check fuel pressure. Low pressure combined with a weak VE pump may cause it to not fire because it can't get enough fuel to the injectors.

Other possibilities: weak or clogged injectors preventing sufficient fuel for combustion. A weak starter and/or battery that's preventing the engine from turning over fast enough to fire off. Timing off or retarded. If the VE pump looks new it may have been installed incorrectly making it out of time with the engine. It may also be a good idea to pull the intake piping off and/or the intake manifold to make sure it's not clogged preventing air into the engine.

Lastly, there is a fuel shutoff solenoid just behind the top of the pump that can fail. If it fails you will crank and get pressure, etc. but it will not fire. It's small and round, about the size of a quarter, with 2 wires coming out of it. I'd start there. Trace the wires too so that you ensure there is no loose wire or short.

 

[Lonesome7.3]

I did find out the fuel pump itself was bad. However, I think at least one of the other parts you mentioned might be a problem as well.

 

[rebel_horseman]

While you're tearing into it, a popular upgrade of the transfer pump is replacing it with a low pressure piston style pump. I'll be doing this to mine soon to keep up with the fuel demands of my modifications. The kit is about $270 which includes the pump.

 

[Lonesome7.3]

I was wonder if I could install one of those on this engine. I know the 4BT guys do it. I was looking into maybe an electric pump. But if the piston style can do the job and is a better pump then I am all about it.

 

[rebel_horseman]

Yep and the piston pump is mechanical. It's pretty much the same retrofit as the 4BT guys and pretty easy. Here's the complete kit:
http://www.dieselautopower.com/product_p/12v 1st gen piston pump.htm

This pump is a good upgrade for mild power upgrades (turbo, injectors, etc) which is all I plan to do. If you want a big change in drive-ability, swap in a DennyT Stage II fuel pin and a 3200 RPM governor spring and a turn or 2 on the fuel screw.

 

[Lonesome7.3]

I would love to get that kit. However, with money like it is a $50 replacement sounds better. The issue I have with that is I will want to upgrade when I swap the enigne over to the Ford I plan to drop it in. Right now I just want to get it running but I do not want to spend the money twice. I wonder if there is a cheaper kit some where. Or, I wonder if I could peice it together from other sources for less.

 

[rebel_horseman]

I looked into both options as well. You could source it individually but you're not going to save a dramatic amount of money. I did not find a kit with all the pieces anywhere else either. I didn't look into an OEM replacement for mine though so it might be cheaper.

I've heard some electric fuel pumps can give you enough fuel to run temporarily.

 

[Lonesome7.3]

I prefer a one time fix. I have other projects that require my attention. I think you are correct, the chances of locating the part from different sources most likely will not save me much if anything. I hate waiting to get this truck running but it might be the best way to go.

 

[Lonesome7.3]

I have found that pump for as little as $98. It does not have the feed line that kit has but I think I can make do.

 

[rebel_horseman]

Yep. For that little money, you could probably source the fittings and spacer as well and save some coin. Make sure you get the spacer for the pump otherwise the piston will be too long and you won't be able to install the pump.

 

[gatorman21218]

Im not helping at all but what gears are in that thing? gotta be WAY low.

 

[Lonesome7.3]

I did not know about the spacer. Thank you for bringing it up.

I have not cracked it open yet to find out. But it is something i am going to have to do soon. I have been wondering for a while my self.