M1151A1 engine issues...among other things

Smoking Joe said:

I got an 1151 back in February of last year. It was supposed to be a running driveable truck. I had a friend check it out before I bought it.

Well it didnt run long. I have driven it a handful of times before i parked it. Each time, it ran progressively worse. It had almost no fuel in it from the dealer. I did not drain it but filled it up with good diesel.

The first time I drove it, it seemed to have a lot of black smoke going up the hills. I got 5 miles (was trying to get to my buddies shop) before i noticed steam on the windshield, checked my guages and it was overheating and i pilled over and shut it down. Let it cool off for a couple of hours while I changed the radiator hoses I already had for it and replaced the coolant. Drove it home and it overheated right as I was getting to my house and turned it off again. Researched it and unplugged the time delay module to put it into the bypass mode.

With the cooling system in overide, it held the engine temp fine. Drove it to my buddies shop a few weeks later to have his mechanics look it over and charge the AC system (which is working, except for the heater core switch so it blows half hot, half cold).

While at the shop, boss called me to work. I drove low speeds on flat terrain, the back way to the city.. 20 miles. It ran fine. On the way home I took it on the highway that had long gradual hills. Up these hills the exhaust was deep black smoke and was losing power so bad i didnt think i could get it to the next exit. Took the exit got it back on level roads kept it 30-40 got home, more or less fine. One 10 degree, short hill by my house and more black smoke and reduced power.

Got the thermostat, radiator cap, and time delay module in from HPG, replaced it and took it for a test drive. Changed the fuel filter too. It started to overheat again so i put into bypass mode again and brought it home. Almost didnt make it up that 10 degree hill. I parked it and walked away from it for 6 months. (Agreement with the wife when I bought it).

I would start it and let it run up to operating temp every month or so. The last time (November), the exhaust smoke was white and I heard a knocking sound so I turned it right off.

After more research, I realize a lot of this points toward fuel injectors or the injector pump. I plan to pull the glow plugs and check the compression on each cylinder in the coming weeks. I have a glow plug remover tool from blackdog and new glowplugs on the way. I was about to buy a kent moore compression guage and adapter. (If compression is good i plan to pull the injectors and have them pop and flow tested. Then look at the timing on the IP).

Does this sound like a good course of action? Am I missing anything obvious? I have the TMs and was working down the checklist when I walked away for 6 months. Im going to pull that out and keep doing the checklist after i check compression. I also plan to empty the fuel tank, drop it and change the tank filter? And the main fuel filter again after i look at the fuel to see if its contaminated. I was getting clean fuel out of the lines when i changed the old filter and it did not look particularly dirty.

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Smoking Joe said:

I got an 1151 back in February of last year. It was supposed to be a running driveable truck. I had a friend check it out before I bought it.

Well it didnt run long. I have driven it a handful of times before i parked it. Each time, it ran progressively worse. It had almost no fuel in it from the dealer. I did not drain it but filled it up with good diesel.

The first time I drove it, it seemed to have a lot of black smoke going up the hills. I got 5 miles (was trying to get to my buddies shop) before i noticed steam on the windshield, checked my guages and it was overheating and i pilled over and shut it down. Let it cool off for a couple of hours while I changed the radiator hoses I already had for it and replaced the coolant. Drove it home and it overheated right as I was getting to my house and turned it off again. Researched it and unplugged the time delay module to put it into the bypass mode.

With the cooling system in overide, it held the engine temp fine. Drove it to my buddies shop a few weeks later to have his mechanics look it over and charge the AC system (which is working, except for the heater core switch so it blows half hot, half cold).

While at the shop, boss called me to work. I drove low speeds on flat terrain, the back way to the city.. 20 miles. It ran fine. On the way home I took it on the highway that had long gradual hills. Up these hills the exhaust was deep black smoke and was losing power so bad i didnt think i could get it to the next exit. Took the exit got it back on level roads kept it 30-40 got home, more or less fine. One 10 degree, short hill by my house and more black smoke and reduced power.

Got the thermostat, radiator cap, and time delay module in from HPG, replaced it and took it for a test drive. Changed the fuel filter too. It started to overheat again so i put into bypass mode again and brought it home. Almost didnt make it up that 10 degree hill. I parked it and walked away from it for 6 months. (Agreement with the wife when I bought it).

I would start it and let it run up to operating temp every month or so. The last time (November), the exhaust smoke was white and I heard a knocking sound so I turned it right off.

After more research, I realize a lot of this points toward fuel injectors or the injector pump. I plan to pull the glow plugs and check the compression on each cylinder in the coming weeks. I have a glow plug remover tool from blackdog and new glowplugs on the way. I was about to buy a kent moore compression guage and adapter. (If compression is good i plan to pull the injectors and have them pop and flow tested. Then look at the timing on the IP).

Does this sound like a good course of action? Am I missing anything obvious? I have the TMs and was working down the checklist when I walked away for 6 months. Im going to pull that out and keep doing the checklist after i check compression. I also plan to empty the fuel tank, drop it and change the tank filter? And the main fuel filter again after i look at the fuel to see if its contaminated. I was getting clean fuel out of the lines when i changed the old filter and it did not look particularly dirty.

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Retiredwarhorses said:

this black smoke is a 95% a clogged catalytic converter, disconnect the down pipe from the converter underneath the truck….i see this on almost every turbo truck that I buy, had 3 last week, I’ve been pointing this out for years on these trucks.

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HoveringHMMWV said:

RWH, so how have you been correcting blocked catalytic converters on these truck's? Simply remove and replace? I was curious about my own some time back, and even posted about it. Watched a lot of videos, read a lot of posts. I ended up flushing with degreaser and LOTS of hot water. Lots of particles and residue was flushed out but I didn't experience a noticeable change except (maybe) a slight decrease in smoke upon acceleration.

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Retiredwarhorses said:

this black smoke is a 95% a clogged catalytic converter, disconnect the down pipe from the converter underneath the truck….i see this on almost every turbo truck that I buy, had 3 last week, I’ve been pointing this out for years on these trucks.

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Smoking Joe said:

Would removing it altogether require tuning the truck? Or does it provide a beneficial role for the engine. I have read some posts on it privides scavenging though, logically I do not see how an obstruction, even one designed to flow, would create a scavenging effect.

What would cause the white smoke and knocking the last time I started it? Stuck injector? It was colder 40s-50s vs the summer.

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