Cummins 8.3 diesel problem.

Spot on for alga. I lost a main injector pump on a 2000 Diplomat.

Now - maybe it's time to check your remaining fuel.

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Your description sounds like what is called algae (actually is not algae, but that is what is referred to as).

Buy a BIOCIDE such as Biobor JF which will kill it. At least in our area, Academy as well as the marine stores carries it. You will still have to filter out the existing "algae bodies", but should not get additional growth.

Have several filters on hand-- that stuff can sure clog up filters.

In the future, be sure to store with the fuel tank full. That minimizes condensation which reduces the changes of algae growth.

Okay, Guys. I changed both fuel filters. I changed the shorter filter first and it looked as clean as a new one.
Then when I took the longer filter off (the one with the sensor wire) "BINGO". The smaller holes, around the perimeter of the larger hole in the middle, were almost entirely clogged with a black, dark brownish looking goo. Sorry about the description, but I don't know which hole is the in-flow and which is the out-flow.
So, I guess I can assume it was starving for fuel. I'm just amazed that it would run at all.

Thanks again, to all that had some input.

If you are getting black smoke and no power, in a diesel engine, then you are getting fuel. What you are not getting is air with oxygen to burn that fuel. So you either have a hose to a turbo on the inlet side collapsing and cutting off air to the turbo charger being able to breath, or you have an air leak somewhere on the compressed air side, that is blowing off air into the atmosphere, instead of into the engine, where it will burn all the fuel injected.

If you mash the throttle on a turbo diesel, you can create these problems, if you ROLL your foot into it slowly, you should not have these problems. Other sources could be air filters clogged or air intake ducting sucking something in and clogging air intake... or a rats nest, or... check everything hose wise from air intake, to air filter, to hoses to turbo charger, to hoses from turbo charger to intercooler, to intercooler hoses to intake manifold.

ScottG wrote:
Exhaust brake wont cause that if it sticks.

Had a Decelerator exhaust brake on my '99 Ford 7.3l and when it would stick closed the engine acted just like the OP described-loss of power and lots of smoke.
I know that is not the OP's problem but wanted to share.

larrylu62 wrote:
No other trips planned until May. I'm going to talked to the 3 local Cummins shops and see what they think before I decide. But it will definitely be going to the shop.

I always try and weigh the benefit/risk ratio of "trying experiments" to troubleshoot problems. If troubleshooting means risking severe engine damage that sure would put bram kes on being hasty. I've yet to have a clogged fuel filter on any of my diesels "fix itself" then have the engine resuming normal operation for more than a few minutes. I have had fuel filters clog on everything from a 30-HP Kubota to a 350-HP Cummins and even my 14-HP Lombordini diesel and they sure did not cure themselves.

You could empty fuel filter contents into a glass jar but don't most newer rigs have some sort of water separator you can take a drain sample? Finding no water or dirty fuel would sure leave me with a strong impression - like a guarantee that the problem is more serious than a mere clogged fuel filter. I've also yet to pour clean fuel out of a clogged filter.

The cost of repairs to a damaged engine would scare the heck out of me.

Grammie wrote:
My 2001 does the same thing. Looses power. Do I have 2 filters? Only change 1 filter.

Contact your chassis maker with your VIN. The part numbers will be very different (very different micron ratings) depending on whether you have:

Primary filter (10 to 30 micron) and Secondary (2 to 5 micron depending on your engine manufacturer's recommendation for your engine).

OR

Only one filter-- see specs for Secondary above.

My 2001 does the same thing. Looses power. Do I have 2 filters? Only change 1 filter.

ScottG wrote:
I would normally say to replace the FF's too and it's still a good idea but they would not suddenly start working right again. Something else is going on.

Scott,

I agree, BUT most shops will start with a filter change, because it is inexpensive and often causes performance issues.

Yes, if the engine was not turned off and performance went bad and then back to normal, it is not likely the cause. But, a clogged filter CAN begin passing fuel if shut off and the algae/dirt drops to the bottom of the filter and all is good again... for a short time.