5 ton running rough

[timntrucks]

i finally got the cummins started today with some hot batteries. it didnt run to good though, first i pressured the tank up via the vent lines and got the fuel to the pump. cracked a line and then after a few pump on the manual it started up. i didnt let it die and let it leak fuel some till i could make it under the hood to tighten it up. ran it for over an hour charging the batties up. it died a few time but started right back up. the fuel gauge was reading aroung 30 lbs. and the throtle response wasnt like it used to be. i finallly hit hte kill switch and nothing. i had to put it in gear and make it die. is the new electric cutoff switch bad? im at a lost, any help would be helpful.

 

[timntrucks]

wow so much help, ill wade throught it

 

[jwaller]

if I had any experience I'd help you but it's going to be another month before I get my cummins.

 

[DaveP]

when you talk about fuel gauge are you refferimg to the cold start pressure gauge?

 

[Scrounger]

I’ll give this one a try. I’m guessing you have an 800 series truck since you have the Cummins. The 800 series doesn’t have an in tank fuel pump, so it relies on the pump at the engine to draw the fuel all the way from the tank(s). The end result is they can drive one nuts if there is an air leak somewhere. If when you use the hand pump on the dash to pump up the pressure and it doesn’t get to “hard” to pump any further you probably have an air leak somewhere. If you have an 816, 818 or an 819 I’d check the lines at the fuel selector valve on the floor first. With an 813 start with the line that runs from the fuel filter/ water separator. If any rubber lines have even the slightest cracking in them change them. There is also a small filter on the IP that needs to be cleaned and checked. Even when they get running it takes a bit of driving to purge the air out of the system. As far as running on there is a chance that fuel may have come from the cold weather starting system. There is a line going in the tube between the air cleaner and intake. As far as the batteries go the 60 amp alternator will take forever and a day to charge the four 6TLs. If they are low it’s better to just put them on a charger.

 

[timntrucks]

i can pump the manual up to a high presure. all the hoses on the fuel se. switch are new, as the fuel lines and the main filter. ididnt know about a smaller filter in the ip, give me the locations and ill get it cleaned, this week check the electric shut off, im thinking that it might have some trash lodged in it making it not close. many thanks guys, this is driving me crazy, i think the start of my troubles was a cracked main hose and a leaky o rings in the manual pump in the cab. started to drip soime fuel while pumping. and as you say it might take longer to get the air out of the system. i wont give up! thanks TIm in mudland. 11 inches of rain here last week

 

[DaveP]

the IP screen is on the top of the IP. it has slotted cap. just be sure to clean the area real good before and during removal. i found no debris in mine. it actually looked new in side.

 

[timntrucks]

super good, ill clean it out first chance, i think i should also go back and charge the batteries some more too

 

[timntrucks]

took the little filter out, looks very clean, but no fuel under the filter? it must still have some air in the system. im back to the batteries i thought i had charged them completly but i was wrong.

 

[WillWagner]

timntrucks,
The filter inside the F/P filters from the inside out...backwards from all others. There is a little horseshoe shaped magnet inside the filter. Just use a flashlight to look and see if there's any metal on the magnet. That filter is only there to stop any debris generated by the fuel pump during a gear pump failure. It serves no other purpose than that. If the primer pump o-rings aer flat or there is fuel dripping from the primer, that will make for hard starting, slow acceleration, white smoke. The seals in the gear pump will hold a vacuum on the fuel lines from the tank to the engine if there are no leaks. Scrounger is right, any line that's hard or cracked needs to be looked at if not replaced. I have seen lines allow air into fuel systems and NOT leak externally! Or, it could be the seals in the pump. Get a clear line and hook it directly to the pump, start it and let it sit. Go back a while later and see if the fuel is gone out of the line. If it is, the seals are junk. If it's still all the way to the pump, there is a leak somewhere from the pump back. Air in the system will also cause a "running on" symptom. Good luck, keep us posted.

 

[timntrucks]

only two lines left that could be the one, both on the return side. little metal one around 6 inchs or so did drip some fuel ocasionaly, and right by it a larger rubber line also a return to the tank has some cracking on it. this might be the one. ill change them first chance. the rain comes back tomorrow so it might be this weekend. great help many thanks i will not stop with this one. and ill double check with a light on the lttle screen. this pump is very shiny and looks super clean inside so im am thinking it has been rebuilt latley

 

[timntrucks]

i finally got it!!! pressured the tank again and got it started and it died. so i presured the tank again a little more than i have been, got a leak on a short fuel hose around the valve below the dirvers seat. looks like i am going to have to take off the tool box to get to it but thats the problem with the air sucking dog. it started to rain so ill get it next time. the box on the running board shouldnt be to hard to pull of. all the hoses there look new but im thinking ill change them all.