NTC 400 cummins with no power, help

[reb87]

Well I finally got my M919 concrete truck shipped here and was fooling with it inbetween unloading grain trucks. It wouldnt start with a jump and I ended up changing all 4 batteries because they wouldnt even hold a charge. I got it running and it starts fine and sounds real good but I dont have any power. I can only get around 35-40 mph and it takes a long time to get there. Also there is no black smoke comming out of the exhaust at any time even when the accelerator is full down. I changed the spin on fuel filter (the only fuel filter that I know of) but when I took the old one off it was only half full. That seems strange. Does anybody have any advice?
Thanks, Ross

 

[WillWagner]

It's normal for the filter to be 1/2 full. Have someone step on the pedal and make sure the throttle lever is breaking over. Most likely an AFC that's stuck. Is it missing?

 

[supermechanic]

Sounds like it's not getting enough fuel.
Start at the tank, pull the dip tube, look for gunk in it.
Check the tank vent.
Check all the fittings and lines up to the pump, look through them or pass a cleaning rod through them, assume nothing is clean.
Cap the line at the tank, back feed fuel from the pump end, then put air pressure on the line to check for leaks.
Open the big screw cap on top of the pump, clean the screen, then re-seal.
If after all of this, you still have low power, look further into the pump.
It's much too easy to assume the pump is at fault , you take the pump to the diesel shop, they bench it, tell you it is good, take your money, you still have the problem.
Been there, seen it

 

[supermechanic]

WillWagner's post brings up a very good point, make sure when the pedal is planked, the throttle shaft is actually at the full fuel position. Ishould have caught that.
(Our posts crossed, I was typing while he was posting)

 

[steelsoldiers]

Great looking truck Ross. What kind of 939-series do you have sitting in the background there?

 

[steelsoldiers]

Oh, never mind, that's the SEORTM truck from the other thread! I can see the shop body sticking out above the stake bed now. Duh...

 

[WillWagner]

I just thought of another easy check. Take the AFC line off and see if there is fuel in the line. There shouldn't be.
If you chose to remove the slotted cap and check the screen, look inside of it. That filter filters from the inside out...there's a little horseshoe magnet in it. If there is any debris in it, it has been run w/o a filter, or the insides of the pump are comming apart. That is a screen so IF the pump fails, the debris won't go into the injectors.

 

[reb87]

Thanks for the help guys I appreciate it. I pulled the throttle linkage off the pump and marked the wot spot. With the linkage back on it lacks about 1/2 inch of reaching wot. I feel kind of stupid here but I cant see how to adjust it. I see I can lengthen the linkage rod but wont that keep the throttle from closing all the way? There are extra holes on both ends of the linkage and I could move the rod down so the leverage would cause a longer movement but the linkage bolt would hit on the pump (on the pump end) and the 5/16 bolt on the pedal end wont go thru the 1/4 holes that are on the bracket(only the top hole is 5/16, big enough for the linkage bolt to go thru)

The other thing is the ball swivel on the pedal end is frozen up. Im going to take it off and get that freed up, maybe that is causing the linkage to bow and im losing some stroke because of that.

 

[tlm47201]

Black smoke means lots of fuel, not enough air. Can ya hear the turbo spool up? Restricted air box, filter, stuck turbo shaft, air boot between turbo and intake, major boost leak. Check those.

 

[steelsoldiers]

I was looking at buying one of these trucks a while back. In preparation for that day, I downloaded the manual off of the http://www.logsa.army.mil site. I'm sure the procedure for the throttle linkage adjustment is in there along with troubleshooting for low power. If you don't want to download the whole thing, then you can look at individual sections on TPUB: http://www.tpub.com/content/trucktractor6x4/TM-9-2320-273-20/index.htm

 

[steelsoldiers]

Black smoke means lots of fuel, not enough air. Can ya hear the turbo spool up? Restricted air box, filter, stuck turbo shaft, air boot between turbo and intake, major boost leak. Check those.

He said there was no black smoke.

 

[reb87]

Ill get some pics posted tonight but adjusting the throttle linkage didnt help. Once I get to half throttle, the pedal moves further but I dont get any more acceleration.

I have a steel line going from the intake manifold going down to the back (engine side) of the pump into (I think it is) the ASA valve. One step outside the asa valve is another line going into the pump, there is no valve just a fitting going into the pump. The steel fuel line goes from the fitting up and tees into another line that goes into the rear of the pump(side towards the cab) and also to the back of the engine somewhere. I havent tracked down where it ends up yet but will go find out now and get some pics of the setup for clarity. Thanks, Ross

 

[reb87]

I also pulled the intake hose and felt the intake side of the turbo impeller and it free wheels with no drag. I only get a little white smoke on startup and no smoke any color when driving or accelerating

 

[steelsoldiers]

The Aneroid Fuel Control valve (AFC) on the injection pump controls the fueling relative to boost or lack thereof.

Check this out: http://www.tpub.com/content/construction/14050/css/14050_137.htm

 

[reb87]

I forgot my camera when I went out to work on the truck, Ill try to post pics tomorrow. I put a boost gauge on and found that I was only getting 3-4 psi in the lower gears (and it builds very slowly) but if I ran each gear up to readline it would build to around 6psi by 14th gear and got it up to 15psi in 16th gear. It was very sluggish until I started to get boost after holding redline in 14th gear. I figured maybe the afc or asa or whatever is getting boost pressure on the pump wasnt working right. I plumbed it into my air compressor(I disconnected the line at the manifold ,plugged the maniflold and hooked the regulated compressor air line up thru the valve) and regulated the pressure at 30psi. When I took it for a drive WOW what a difference. I couldnt read the boost gauge because it was dark but it definetly has more power. Do I need a new valve or what?

 

[WillWagner]

oops didn't read the above post

 

[WillWagner]

Stuck AFC or a hole in the bellows. Hook it back the way it's supposed to be and see how it drives. If it is back to the low power thing AND the pump is going to full throttle, you need to have the pump repaired... the AFC can be done w/o doing other calibrations to the pump.

 

[tlm47201]

OOps. My screen cut the "no" off the post. Makes a big dif, guess i ought to read these while awake. LOl.

Black smoke means lots of fuel, not enough air. Can ya hear the turbo spool up? Restricted air box, filter, stuck turbo shaft, air boot between turbo and intake, major boost leak. Check those.

He said there was no black smoke.

 

[reb87]

Ive been busy with harvest so I havent had time to work on the truck. I dont know my pt terminology but pictured closed to the camera is a bleeder plug,then a steel fuel line(where my manual says afc breather) then the valve I want to replace(with the air boost line from the manifold) on the back(engine side) of the pt. What is it called? The cummins manual I have from our irrigation motor shows a afc breather where my truck has a fuel return line plumbed in and calls the thing I want to replace a asa. Should that valve allow air to go into the pump or is it the bellows you refer to. I took it off and air blows thru it. Thanks, Ross

 

[reb87]

Also how much boost should this engine put out when working hard? Thanks