NHC-250 IP rebuild? - Page 2 - Steel Soldiers::Military Vehicles Supersite

Crash_AF · 02-20-2008, 11:34

Quote:

Originally Posted by 73m819

jason, you would be SUPRISED how small a air leak will cause this, does it surge at idle

So if my 818 surges at idle and is a bear to start after sitting for a day, then it's probably an air leak in the feed lines from the tank to the pump?

Later,
Joe

73m819 · 02-20-2008, 11:37

an air leak almost for sure, where the air leak is a whole ball game by it self

Crash_AF · 02-20-2008, 12:59

Is there a somewhat easy way to track the leak down or is it just chasing hose until you find the problem?

Thanks,
Joe

halftrack · 02-20-2008, 13:01

Start chasing. You might want to get your running shoes on.

martinsaunders06 · 02-20-2008, 15:31

my 816 exactly the same,wont start after a few days but also if left idling becomes fluffy idling and poor throttle response.have checked tank and lines and are ok.injectors have been done as well.i did find that pump always felt damp with fuel from around rear of casing but not enough to drip tho so i came to conclusion it was sucking air in from a gasket/seal.the pump is away at moment being checked/done

mitchellracing · 02-20-2008, 19:39

Mine was sucking air and would leak down after it sat thats why i rebuilt the pump . I started at the tank and put all new hoses on it and all that got to the pump and figured it was next. As i started taking the pump apart I found between the two havles where the gears are there was a fuel trail where it was leaking kinda narrowed it down. the fuel dampener orings were also leaking that might be what you were calling a diaghram . As far as to putting new seals in the pump its not a problem as long as you dont move the adjustment screws. A neat trouble shooting tip with a pt pump ,when ya mash the gas if its slow to accelerate but doesnt slow right down when ya let off its sucking air. If it dosent accelerate but returns to idle when ya let off the pump is worn.

Crash_AF · 02-20-2008, 23:38

Quote:

Originally Posted by mitchellracing

A neat trouble shooting tip with a pt pump ,when ya mash the gas if its slow to accelerate but doesnt slow right down when ya let off its sucking air.

That's EXACTLY what mine is doing...

Hooty481 · 12-31-2011, 15:39

I hate to start a new thread so im gonna post here and i was reading this entire thread hoping for pictures at the end but i was dissapointed.

My pump is leaking at the throttle shaft. truck runs great all of the time and the fuel bleeds off after a few days but how hard will it be to change the o-rings on the throttle shaft. I have been told i will have to take the entire pump apart. is there any schematic or tm that goes into detail of this.

I can get a reman pump for 375 bucks and am thinking of going this route. What do you think.

crasheej · 12-31-2011, 20:00

One of the TM's has all of the info do the rebuild. I'm not at myplace so I can't go look it up for you. sorry

Floridianson · 01-01-2012, 14:04

My .02 take them to the correct injection shop let them do there stuff. Have them bring up the rail pressure to 180 on the NHC250 and add a little fuel across the board.