M816 power questions - Steel Soldiers::Military Vehicles Supersite

AMGeneral · 10-22-2006, 20:47

Ok,here's the problem.My 816 just doesn't seem to have the power it should,plus the engine seems to have much more "combustion knock" under load and emits very little if any smoke out the stack,So far this is what I have done to the truck,

Replaced all rubber suction lines from the fuel tank to the Injection pump
Rebuilt the Injection pump
checked all suction lines for air leaks from the tank to the pump
set all the valve and injector clerances

still the truck seems to have low power,I've seen other NHC powered trucks that bellow smoke like a freight train,yet mine smokes very little.

Any suggestions?

red devils dude · 10-23-2006, 10:35

it is a 36,000lbs truck with 250hp, but have you re checked the fuel filters? checked the fuel pump for pressure?

AMGeneral · 10-23-2006, 20:33

Fuel filter has been changed regularly(every oil change).It would help if I had driven another 800 series truck to compare it to.All I have to compare it to is my Multifuel deuce and my M52A1 Mack powered tractor.The Mack will outrun and out pull it hands down running on 5 cylinders!!Haven't checked fuel press,does the NHC have a check valve in the head /return line that keeps a regulated pressure to the injector cups?

red devils dude · 10-24-2006, 09:25

I woundnt think so but I'd have to check a manual.

poppop · 10-24-2006, 19:14

My M813 smokes very little and I had some questions about power on the 750 mile road trip I just made. It would strain going up hills with no load in the bed. The fuel filter was new and the old one I took out was clean as a whistle so no junk in the tank. I followed Ron's tractor wrecker for a few miles and he could pull away from me and his truck boiled smoke.

73m819 · 10-24-2006, 19:22

theres a little fuel filiter in the ip, check that for fuel restuction, most 800 owners dont know about it, let me check some manuals and i wiil come back with more info on it.

thanks lloyd, letting me know about the smoke and power, the 819 will do 65 all day on the freeway at 2000, but hates longggggggg steep hills

poppop · 10-24-2006, 19:32

Hey Ron
It was upsetting to have you pull away from me with your heavy truck. I will try to have that fixed before we convoy again.

73m819 · 10-24-2006, 20:15

thats why i slowed down, thought you had broke down for a minute till saw you come around the bend, now that i have a bumper i can always push

TacticalTruck · 10-24-2006, 21:19

Are you guys running stock springs and fuel buttons in your injection pumps? I picked up a purple sping and a #18 fuel button but I haven't had a chance to put them in. My M816 just keeps 53mph on the flat.
Jeff

AMGeneral · 10-24-2006, 21:23

I had mine turned up a small bit when the injection pump was rebuilt.Has anyone had a problem with the injector cup seals going bad on their NHC 250?,I'm probably grasping at straws here.