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PC160LC-7EO Diagnostics

J

josephny

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Yesterday I put 15 gallons in and it ran like crap. So I thought maybe the concentration of remaining contaminants in 15 gallons of fuel was too high, so I put another 10 gallons in today.

With newly replaced injectors, how would combustion gas into return fuel? And is there something I can check to narrow down what's going on?
 
funwithfuel

funwithfuel

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Did you replace the copper seals at nozzle tips? Did you clean the bores? Did you blow out the hold down screw holes? Are the injectors tightened down properly?
You said yourself its running rough, but your rail pressure is sufficient. It should be happy as a clam. I'm guessing you received a bad or failing injector. New or reman doesn't always mean good.
 
funwithfuel

funwithfuel

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josephny said:
Yesterday I put 15 gallons in and it ran like crap. So I thought maybe the concentration of remaining contaminants in 15 gallons of fuel was too high, so I put another 10 gallons in today.

With newly replaced injectors, how would combustion gas into return fuel? And is there something I can check to narrow down what's going on?
Click to expand...
Take your return hose off, use another hose and run into a bucket, odds are you'll see foam, bubbles and/or mist.
 
J

josephny

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Sullivan County, NY
If the fuel in the tank is already dark, will looking at the return line fuel help?

sounds like we are looking for foam, bubbles and/or mist and not the color, right? And that will tell is if the problem is at the injectors?
 
J

josephny

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Sullivan County, NY
Here's where we stand today:

1) Coolant level is fine, so that rules out mixing and burning coolant
2) Changed oil (again) but it looked fine (a little thin)
3) Disconnected hose from pump that pumps the return fuel back into the fuel tank. With engine running, it was a total mist (80% air).

Here's a video and pictures of the mist/steam that's coming out and what was collected (pretty black):


diesel-black.jpg mist.jpg
 
funwithfuel

funwithfuel

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That is totally a bad injector or poor combustion seal. You'll need an old injector line nut and a ball bearing. You remove one pipe at a time. Cap rail with ball and nut. Start and check for that mist. If it's there, move on to the next. The one that eliminates the mist is your dud. First I would remove, clean and check combustion seal on each injector. Make sure you don't have a big wad of crap preventing a good seal to the head.
 
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josephny

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Wow, that is great knowledge you have!

Any chance you know (or can point me to) the diameter and thread for the rail cap needed? I don't have an old injector line nut.

Thank you!
 
funwithfuel

funwithfuel

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It's a tool you can purchase from Cummins. I don't know the specs on it. But it is made specifically for this task. Just be careful, the pressures are dangerous
 
funwithfuel

funwithfuel

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The only option I can come up with is to order up a new fuel line and sacrifice one of yours or purchased a tool from Cummins. Whatever you get to cap off the fitting it will have to be steel, brass could simply blow off under the pressure
 
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josephny

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Location
Sullivan County, NY
When I got the new injectors I bought 1 extra. What do you think about swapping that one alternative injector in, one cylinder at a time? It's not as complete of a isolation test, but if it's purely the injector, it'll work, no?
 
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