Dosser injector fitting

[Lead_sled]

I’ve been chasing a leak for a few days now. Didn’t know what it was or where it was coming from. Only thing I knew was passenger side, light weight fluid. Thought it was a diesel leak at first due to the fluid. Anyways, I was right, it’s a fuel leak and seems to be coming from the dosser injector fuel fitting.

Several questions. It appears to be a low pressure line due to the clamp fittings inline. I can’t see any leaks while idling.

How much pressure is on this line?

I put my wrench on the fitting and it’s loose.

Is the braided hose supposed to turn with the fitting or is it independent?


Now to introduce myself for being a new guy.

Just bought an ‘09 KW T660 with the Cummins ISX EM871, 10 speed. I’m a new owner operator and have been driving trucks casually for 4 years. Mechanically inclined on gas engines and smaller Diesel engines such as the TDI. Picked up the truck from my uncle who meticulously keeps his equipment. Engine has 400k on overhaul. New radiator, a/c compressor, ecm. Truck runs strong. As with anything used, I’m sure it’ll need some TLC.

[Lead_sled]

I have plans to do the EGR service work, cleaning. As with the fuel leak, I’m literally pissing fuel in the wind. Right now with the leak, getting around 4.8 mpg.

[Nilao]

The nut should turn independent of the fitting. I think the pressure on that line is the same as the injection pressure...260 to 300 psi. Those clamps should be compression clamps.

[Lead_sled]

Thanks for the quick reply. I’m waiting for it to cool down a little, then I’ll try to back it off first before trying to tighten back down on it.

It’s crazy with that pressure that I can’t see any leaks at idle. But it’s sure blowing pretty good when hauling down the road. I’ve got fuel residue from that point to the rear of the trailer.

[Nilao]

That line only has pressure during a regen. The ISFM controls fuel supply on the line.

[Lead_sled]

Next question. Does the truck regen while driving or only while parked? There’s has to be an explanation for why so much fuel residue underneath and it’s spraying pattern.

[Nilao]

Only while driving unless you do a forced regen.

[Lead_sled]

Well, I guess that explains my issue. I’ll get it tightened and see how she does.

I parked 2 nights ago and the entire passenger frame rail and air tanks were dripping. Hopefully I can save some fuel now.

Thanks for your expertise and quick reply.

[Nilao]

I pmd you my number if you'd like to pick my brain in real-time lol