Misfire from possible fuel issue?

I was driving back from the hardware store one day and noticed the truck start shaking from throttle input. Then found smoke was pouring out of the exhaust. Stopped at home and the thing still runs but sounds kinda like a minor misfire and the whole truck shakes a bit. I have replaced injectors and even swapped some around. I have found that the driver side 2nd cylinder injector is completely soaked every time I pull it. Fuel has taken over my oil pan.

After weeks I gave up and dropped it off at a shop. They think air is in the system from somewhere. I Had to pull the truck from the shop due to me leaving the country for 9 months. I’m completely lost and have no idea where to start.

Here is a video:
Edit: I have pulled the fuel filter, replaced it, re primed and the issue is still present

Uhh, that shakes the fillings out of your teeth!

Air in the system... dont think so. The system bleeds it selfe very quickly.
I suspect a bad injector or bad timing.

Quastion. How is it starts? Quick as usual or does it struggle?

smillysmil said:

I was driving back from the hardware store one day and noticed the truck start shaking from throttle input. Then found smoke was pouring out of the exhaust. Stopped at home and the thing still runs but sounds kinda like a minor misfire and the whole truck shakes a bit. I have replaced injectors and even swapped some around. I have found that the driver side 2nd cylinder injector is completely soaked every time I pull it. Fuel has taken over my oil pan.

After weeks I gave up and dropped it off at a shop. They think air is in the system from somewhere. I Had to pull the truck from the shop due to me leaving the country for 9 months. I’m completely lost and have no idea where to start.

Here is a video:

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Edit: I have pulled the fuel filter, replaced it, re primed and the issue is still present

Click to expand...

The next step is to do a compression check on all the cylinders.
Some questions
Do you have positive fuel pressure when you open the water drain valve while running?
How bad is the fuel contamination, how much over full is the crankcase and is it getting worse fast?
Have you checked the fuel return check valve for contamination and the return system to make sure it is not plugged?
There is basically three ways to get fuel contamination in the oil, Bad IP seals, Bad lift pump and bad injector or dead cylinder.
One other thing you can do is a balance check, loosen each injector line one at a time, you should notice the same amount of RPM drop for each cylinder.

What type of vehicle? If you have a 6.2 engine, the harmonic balancer has a nasty habit of getting loose and you start shaking like crazy.

Edit-seems like your sig line states 2004 M1123…

If you’re harmonic, balancer itself has gone bad, that can also cause shaking.

That is in addition to all the other gremlins in the fuel injection system

[EDIT- Looks like you did indicate year and model, BUT iPhone doesn’t show unless in landscape position. Sorry] It helps best to let us know what year vehicle and what type of vehicle, etc

frauhansen said:

Uhh, that shakes the fillings out of your teeth!

Air in the system... dont think so. The system bleeds it selfe very quickly.
I suspect a bad injector or bad timing.

Quastion. How is it starts? Quick as usual or does it struggle?

Click to expand...

I was thinking the same thing. I don’t see how that could be air. Injectors were almost 6 months old when this issue came about. I was almost positive it was an injector on the driver side. Swapped around injectors on the driver side to no effect. So I ordered 8 new ones, replaced all on the driver side and continue to have the same issue. Threw up my hands and gave up before i did the passenger side. Because I was not about to do the other set in 20 degree weather again. Left it for my mechanic to do it and 5 weeks later nothing was done.

Every time I pulled the injector on that one cylinder it was soaked leaving me to believe maybe no compression. I don’t have blowby, so I’m not sure what’s going on. Maybe a valve train issue. I might have to bore scope it or something. I’m hoping it’s timing. Maybe timing chain jumped a tooth. Man I hate diagnosing

it was weird, just driving along 35-40mph and then out of nowhere misfire, shaking, and latter smoke from the exhaust. Temps were barely 200 and oil pressure was solid.

TOBASH said:

What type of vehicle? If you have a 6.2 engine, the harmonic balancer has a nasty habit of getting loose and you start shaking like crazy.

Edit-seems like your sig line states 2004 M1123…

If you’re harmonic, balancer itself has gone bad, that can also cause shaking.

That is in addition to all the other gremlins in the fuel injection system

[EDIT- Looks like you did indicate year and model, BUT iPhone doesn’t show unless in landscape position. Sorry] It helps best to let us know what year vehicle and what type of vehicle, etc

Click to expand...

My apologies it is an ‘04 1123. It does appear to have a reman engine. Which I would assume is a 6.5 and I have no blowby. As an experiment, I took off the belt thinking maybe it was a pulley or something but there was no change. I did not think to look at the harmonic balancer when doing so, so I don’t have an answer on that one.

I had just filled the tank the day before (from the same station I always go to) so I suspected fuel contamination with gasoline. Took a sample and did a lighter test. No effect so I assume it was good. The funny thing to me is this is the first full tank without a diesel treatment

Mogman said:

The next step is to do a compression check on all the cylinders.
Some questions
Do you have positive fuel pressure when you open the water drain valve while running?
How bad is the fuel contamination, how much over full is the crankcase and is it getting worse fast?
Have you checked the fuel return check valve for contamination and the return system to make sure it is not plugged?
There is basically three ways to get fuel contamination in the oil, Bad IP seals, Bad lift pump and bad injector or dead cylinder.
One other thing you can do is a balance check, loosen each injector line one at a time, you should notice the same amount of RPM drop for each cylinder.

Click to expand...

I will have to check again just to make sure. But yes I did have positive pressure with the drain valve open while running. It did not stall.

I cannot say for sure how far I drove after this issue occurred. Maybe 3 miles, along with the moving from place to place while on the farm. But in total I have noticed a good amount of contamination. I first realized it when I checked my oil while diagnosing. I was 1.5-2 quarts over and sucked it out assuming I had overfilled on my top off. I soon realized I was wrong.

I have not checked the check valve. I guess I will have to look in the -20 for that one.

I will have to do that injector crack process again because I don't think I was really paying attention because they all sounded the same to me.

As an experiment I tried gauging the exhaust on each cylinder with an infrared thermometer, it was not as much help as I had anticipated. Although the exhaust from the driver side #1 cylinder (right under the generator) was noticeably cooler than the rest which I just blew off as wind from the back side of the generator cooling it somehow . The injector after that one (I call #2 driver side) is the one that has come out soaked everytime and it’s temperature seemed fine.

That much fuel really sounds like a bad lift pump, the IP has a weep hole that should flood the valley under the IP if that seal goes out and a single injector even on a really dead cylinder could not cause that much diesel into the oil.
The check valves are in front of the fuel tank, most remove both of them completely, they have and will be a source of failure.

Mogman said:

That much fuel really sounds like a bad lift pump, the IP has a weep hole that should flood the valley under the IP if that seal goes out and a single injector even on a really dead cylinder could not cause that much diesel into the oil.
The check valves are in front of the fuel tank, most remove both of them completely, they have and will be a source of failure.

Click to expand...

I was thinking lift pump as well. After a YouTuber I watch uploaded a video last week explaining his situation with a bad lift pump it got me thinking.

His pump ended up filling his geared hubs with diesel. I still have those lines cut from demil (and my own laziness) so as far as I know, I don't have diesel in those places.

If the check valves are in front of the fuel tank I will definitely have to take a look.


Edit: Also like to add that it starts up right away almost every time. Although I have noticed 2 times this weekend where it was cold and it took an unusual amount of revolutions to start. Where this truck usually starts incredibly fast every time.

I once filled my tank at a discount station (grocery store chain) in Wyoming, and then, out in the middle of nowhere, it started running rough, and almost died. It was blowing so much black smoke that the "Coal Rollers" would have been jealous. It finally died, and I almost could not get it restarted. After checking the filter, I wound up cleaning out about a coffe can of sludge that looked like a thick brown slime blob. The filter was actually collapsed, like the injection pump pulled a vacuum. After everything was cleaned up, it took about 100 miles to run normal again. With the small quantity of fuel that is injected, it does not take much bad fuel to mess up the system.

I had the same issue here nearly a year ago. In my case it was dirty old diesel out of the "red offraod fuel" tank.