About a year ago I had the fuel injector pump replaced on my 5-ton NHC250 because the truck was barely running and had a minor leak at the injector pump "weep hole". Now it's running bad again with a much worse leak at the weep hole on the rebuilt pump. The truck probably has less than 20 hours and 200 miles on the replaced pump! Any thoughts other than the obvious, being replace the darn thing again at the tune of about $2K? thanks!
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5-ton NHC250 Injector Pump
- Thread starter captcarc
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pumps only cost about $600 to rebuild and an hour of your time to install. not driving the truck is as bad as anything else that can be done to them. Orings can go bad at anytime. maybe that just replaced the basic stuff and only some of the orings.
I have the take off injection pump from my NHC250 that had 170,000 miles on it in 2 yrs and it never leaked at all.
I have my take off pump for sale if you are interested.. You would have to add a dual fuel line setup to your truck if you don't have it already. My pump is about 40 percent over stock and a #16 button.
sandcobra164
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My injection pump blew the exact same seal about 2 years ago. I wasn't quite as fortunate as the weep hole was plugged so it blew out the seal on the other side and pumped about 7 1/2 gallons of diesel into the engine oil. I guess you could say I got an advanced engine flush on that trip. Removing the injection pump is honestly not that difficult. Break it down into simple tasks. Remove the throttle and transmission linkage, remove fuel lines, remove wires and lastly remove the bolts that hold the flange to the back side of the air compressor. Mine already had the 7/16" 12 point bolts next to the block. My only special tool was a curved 7/16" 12 point box wrench. You can do this. My rebuild was only $325 or $350, can't remember exactly. For $2000 I could make money bringing you a rebuilt pump and putting it on traveling from Georgia and getting a hotel room overnight. This is not a hard task to complete and myself and other members on the board will talk you through the process.
sandcobra164
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I used R&S Diesel Injection, 612 W Roosevelt Ave Bldg A, Albany, Ga, 31701. Their phone number is 229-435-0578. I'm not saying they are better or worse than the business Simp recommended, simply supplying the information on the company that rebuilt my injection pump 2 years ago.
There is no timing. Just put it back on. And fire it off
sandcobra164
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Bottom set of wires is for the ether start. It won't allow a shot of ether unless there is fuel pressure inside the pump which only occurs when the pump is primed and the engine is turning over. The only wire on top would be the one wire going to the fuel shut off solenoid. There is no timing involved with the pump. You should have a rubber ring with 6 ears on it that came out with the pump or is still on the back side of the air compressor. Make sure that is in place when you re-install the pump. Think of the pump itself as a booster/metering pump. Injection timing is controlled by the camshaft, the pump only controls how much fuel is available to be injected on a Pressure Timed (PT) fuel system on these trucks.
RhinoTAC
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Hey I am in Tyler and need my pump rebuilt on my M813, where in east Texas did you go and what was the cost for everything? Thanks
Finally got 5-ton running quite well with the rebuilt injector pump. Thanks for everyone's input. The only problem now is that I connected wires 54 and 54A onto the BOTTOM of the two injector pump solenoid poles and was rewarded with a lot of exciting smoke in the engine compartment and inside the cab when the ignition switch was turned on. (A previous mechanic had disconnected those wires so I didn't know which pole to connect them to.) Several people had told me the bottom pole, but now it seems that the top would have been correct. Everything seems to be fine but have to turn off the truck manually. Any quick tips on what 54 and 54A connect to from the solenoid? Thanks!
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54 goes to the fuel Solenoid, 54A goes to the STE/ICE Diagnostic Connector. They both have 24v on them when you turn the truck on.
They go to the starter switch in the cab.... They T after that and the 3amp ABS fuse (yellow wire) is branched off from that along with 54a that goes to the STE and to the solenoid If you torched the wire. Just run a new one from the Switch or after the ABS link in and go from there out under the hood... OR if you want another anti theft add a switch and have that as its own switch to power the solenoid up before starting.
Thanks simp5782! I'll probably check back in with you after I pull that starter switch and look at the fried wires. From what you're saying, it sounds like I could run a 24v hot all the way from the batteries to the solenoid with a switch in between. With my torched wires, I wonder if my ABS is now nonfunctional. Frank
Pulled starter switch and everything looked good. Looked under dash and found 54 burnt through. Replaced 54 from just before the T back to the solenoid. Now, switch powers voltmeter in dash when closed, which is a positive step, but solenoid is still non-operational. Pulled 3amp inline fuse near T and it looked OK. Do I have to reroute 54A (also burnt through at solenoid) to return solenoid to functional operation? Suggestions? Thanks!