Need Help With a Lack of Power Issue

[dtdoyle01]

I hope someone can help me. Here’s the story. I have an 84 M1028 with 8700 original miles. I was towing an empty M105 1½ ton trailer up and down some hilly terrain. I lost power going up a hill and started to blow a lot of white smoke. The truck stalled and I couldn’t get it to start for longer than a second or two. I drained some water out of the fuel filter, but the truck still wouldn’t start. I towed her home.

Now for the maintenance:

I modified the fuel filter to a spin on type, replaced the lift pump, found two broken glow plugs, and replaced them all. I also found the two vacuum lines on top of the engine that had long since fell apart and replaced them. I dropped the fuel tank, cleaned it out, blew the lines and installed a new sending unit. I replaced all the rubber fuel lines. I checked the one way return valve on the top of the IP with the glass ball, and it was clear. I checked the fuel flow from the lift pump and it checked good.

The good news is she runs and starts up every time.

The bad news is I have no power. I can’t get the truck up past 45 mph, and when I hit the brakes she stalls, but starts right back up.

Any suggestions as to what to look for next would be greatly appreciated.

Thanks

 

[citizensoldier]

Sounds like a injection pump issue. Maybe some of the pros will chime in.

 

[dtdoyle01]

I guess no one has a clue as to what else I should check on my M1028.

 

[armytruck63]

If you have access to a Diesel compression tester, it might be a good idea to run a compression check, just to see if something let loose in one of the cylinders. You could have a hole in a piston from the broken glow plugs. A compression tester for gas engines won't work - you'll damage the gage with off-scale high readings.

I have no clue on the stalling when braking issue.

 

[Jeepsinker]

Is it still smoking? You may have a blown head gasket, or you may have a bad injector.

 

[dtdoyle01]

Thanks Armytruck63,

I'll have to pick one up. I only have one for a gas engine. After I ironed out all the other issues that arose at the same time as the power loss, I took a look at the exhaust smoke color and if the anti-freeze and oil had mixed. They hadn't, so I figured my head gaskets are OK. I almost wished one was blown. Then I could fix it and be done with it.

 

[Skinny]

If cooling system looks good you are down to incorrect timing (bad IP or gears), misfire (white smoke on one side only more than likely), or an injector is failing.

Attack things one one at a time and start with the cheapest/easiest items first. You will end with either a IP or engine

 

[nyoffroad]

Any smoke at all? The reason I ask is I had a glow plug break off when working hard going up a hill. That engine knocked bad for a few seconds then the knock dissappeared and a miss or skip kinda replaced it. I was limping it home when all of a sudden it smoothed out and ran fine. I can only assume that the broken tip somehow jamed the exhaust valve open causeing the skip. I never did pull that engine apart to see if or what was damaged and used it for a few more years.

 

[dtdoyle01]

Today I picked up a diesel compression gauge. I will check compression tomorrow and post what I find.

 

[dtdoyle01]

I checked the compression this morning. All 8 were between 410 to 425. This is what I expected to find since there is only 8700 original miles. The timing marks are lined up. I have no smoke coming from the exhaust at all. I am starting to think it might be the IP. My question now is, If I advanced the timing, will I get more power out of her for now until I can get the IP rebuilt?