White smoke

[kevman6]

Have a 2013 Cat 950k that is gives off white smoke at higher RPM.and Low fuel pressure light. I'm checking for fuel leaks but suspecting a restriction somewhere. Will be changing filters today. Any other ideas are well appreciated. Slight loss of higher RPM, but runs well with no smoke at idle. Hasn't been run in awhile.

 

[thepumpguysc]

A low pressure lite & white smoke means the pump wants more fuel than the "tank" can supply & its pumping air or thin fuel..
Look closely for a collapsed rubber line.. u might not be able to see it if its internal.. just do it the old fashioned way & go down the line squeezing it.. or do what we do now & replace them..
CHANGE THE FILTERS 1ST.. test it.. any better? yes, leave it alone. NO, check the rubber lines for leaks & real hard or soft spots.. replace as necessary.. any better?? yes, leave it alone.. No, check the fuel pressure & replace the lift/supply pump..
Good luck

 

[kevman6]

Thanks pumpguy
Will post what I find

 

[kshansen]

Thanks pumpguy
Will post what I find

And be nice to those of us with SIS access and post the S/N so we can look up information you might need like pump spec's and such!

 

[kevman6]

950k fer00308 Just bought this machine.
Filters didn't fix the problem. Maybe ill try putting air back into the tank to clear and restriction. Only 9 degrees out, so waiting til I can get it inside where its warmer. Idle and sitting still with RPM increased gives off no white smoke, only under higher RPM when driving. Still gives Low Fuel Pressure warning and Code. Fuel filler neck cap inside was pretty dirty. Screen was clear, but fine dirt may have gone past it. Still hunting

 

[kevman6]

I noticed when I changed the filters, that the electric primer would not fill the filters. I filled them manually and the engine started right up. When I opened the fuel cap, I heard suction. Is there a tank vent somewhere that could be plugged, or is the cap supposed to be vented?

 

[JPV]

If the cap has a big plastic semi circle looking protrusion on half of it that is a filter for the vent. Those are supposed to be replaced every so often according to the book because they do plug and will cause the problem you are having. Just loosen the cap when it starts having the problem and see if it clears up. The other thing if that doesn't work is to blow the lines back to the tank from the filter like you mentioned, there are usually some 90 degree fittings in there that will plug with crud.

 

[kshansen]

If the cap has a big plastic semi circle looking protrusion on half of it that is a filter for the vent. Those are supposed to be replaced every so often according to the book because they do plug and will cause the problem you are having.

Good point JPV!

If your cap looks like the one below the kit with the red box is the part you need. Even if this isn't 100% of your problem it is a good idea to replace every so often, more often if working in very dusty conditions!

 

[kevman6]

Thanks for thee reply, I changed the Cap and the small inline filter twice. The white smoke is 95% gone. It will come back for a minute or two then go away. There is some fuel or oil residue that coats the exhaust stack. The engine was very dirty with dust residue all over it. Im thinking the crankcase ventilation system could be clogged, of some other more serious problem. First step is to power wash that engine so we can see it. Finally got weather above freezing. RPM is back full and runs like a beast. Just still concerned with the residue on the stack.

 

[kshansen]

Well the ventilation system does have a replaceable filter in it would be worth a check at least.
That 352-6008 kit lists for about $25.00.

 

[kevman6]

Well, still have heavy white smoke back again. display says "Low fuel rail pressure", and "Pressure relief Valve active"
Odd that I have Low pressure at the rail and valve relieving the pressure if that is what its doing when Active.
How often do these valves fail, and is there a way to test it. Can it be capped off for testing? Any ideas are appreciated.

Also, RPMs are down again because of low fuel delivery i would guess.

 

[thepumpguysc]

IF the valve is faulty which is VERY common.. it cant build pressure in the rail.. the valve is dumping it back to the tank.
Take it out & inspect it.. shake it.. if u hear it rattle, its bad.. it has to hold pressure..{rail pressure}
I don't think they're expensive.??

 

[kshansen]

Well if the valve being talked about is the one in red in picture below it looks like they run around $120

 

[kshansen]

And here is the trouble shooting instructions for a Fuel rail Pressure Problem:

 

[kevman6]

Finally got a warmer day, 33 deg. Got it cleaned up and will try to check the pressure relief valve today and drain the fuel tank. Then I know i"m not pushing dirt back into the system. The step by step for low fuel pressure diag is helpful also. Thanks for the input.

 

[kevman6]

While checking the fuel system, I found that the primer pump makes noise, but doesn't pump fuel. I ordered the pump which should be in today. Hopefully this clears up the "low fuel rail pressure" problem and the "fuel rail pressure relief valve-active" message. I don't understand why I would have an active pressure relief valve if I'm starving the system for fuel. I will see today.

 

[92U 3406]

Those little primer pumps seem to crap out often if they're the ones I'm thinking about. On the smaller stuff with the C3.3B's (and similar size engines) they'll actually run just fine in most cases with a failed primer pump. Just a PITA to get them started after changing the fuel filter.

 

[kevman6]

Well, the primer pump got rid of the white smoke. The fuel rail was getting starved and with the pump not delivering fuel to the filters, it was losing flow. But... now I have some blue smoke upon hard full throttle under load. I don't have blow-by, but blue exhaust smoke. 8000 hours on a C7. Looks like someone put a replacement turbo on before I got it. Not sure where to start looking. I read that it could be injector seals or valve seals. Any info would be helpful. Runs well and full power. Just would like it right

 

[kevman6]

I did a manual regen and cleared up the blue smoke. Cat said it would have lots of residual soot and residue in the DPF. They said now go work it hard and let the computer reset its parameters. Nice to see clean exhaust again. Thanks for all the input and help. I hope it doesn't come back.

 

[kevman6]

There is actually a recall on these pumps for all the 924K, 930K, 938K, and a separate one for 950K dated 11 july of 2014. It covers many other models also. It describes the exact problems I was having. The recall ended 13 july 2016. TEBE1133-00 If your having this problem, Its an easy fix once you find this Service Letter. The transfer pump actually draws heated fuel back through the return line, and can't supply the fuel required to feed the high pressure fuel pump.