Broken In Iraq, help

[WytchDctr]

Hello, I am currently in Iraq. I have the 6.2 in my truck and it has a problem. Here is the background story. When I got it the truck it was weak, very slow compared to other trucks with the same armor etc. A group of competent mechanics took the truck and made it run better. For the last 6 months it has run great only a few suspension issues but nothing with the motor. Well about three weeks ago we went on a long drive. When I got back it was idling rough, very rough and some noted power loss. I went home on leave and when I came back my guys had just got back from an even longer/harder drive. It was idling so low/like crap it couldn

[More Power]

SGT,

In my correspondence with other HMMWV mechanics in the region, I know some of them turn up the fuel rate in an effort to improve power. The added weight of the armor cuts into performance, and I can understand their need to hurry things up a little.

Unfortunately, what can sometimes happen is that the fuel rate is increased beyond what the engine can efficiently burn and the exhaust temperatures go well beyond design limits. This can result in damaged pistons, which affects piston ring sealing and further reduces power.

Assuming the fuel injection system is operating within specs, I would want to see a compression test run on this engine. You should be seeing 300-400 psi per cylinder at cranking speed after 4-6 "puffs". 300 is the low side of acceptability, and anything under 300 would tend to reinforce a weak engine problem.

However, an engine damaged by excessive exhaust temperatures usually results in one or more cylinders with much lower cylinder pressures than the rest. If you see this, you'll know you've got some bad pistons. The lowest reading cylinder should not be lower than 80% of the highest.

So, do a compression test, then report back.

Jim

[WytchDctr]

That makes alot of since with what could have happened. I am pushing for a compression test right now. I was going to get a video of the truck running poorly this am (my lil camera has horrible sound pickup so I want to take the vid when its at its worse) but my boss beat me to the truck today and had it warmed up, once warm it idles better. Ill try again tommorrow and post it once I find someone to host it.