Has anyone with a 3rd gen. Cummmins had a fuel leak somewhere around the injector lines? Mine started leaking fuel about a month ago, but only under high-load/high-rpm conditions. The fan would force the fuel onto the driver's side firewall & now it smells like diesel when I turn on the heater!

I've tightened up all the line nuts I could get at. (some mechanics were cracking the line nuts to try to bleed air in the past & a couple were not to specs). I tightened all the fuel related components that I could get at.

I studied the Cummins fuel delivery system for any clues. On the weekend I put a cardboard shield at the front of the engine to keep the fan from spraying the fuel on the firewall & I put 2 pieces of cardboard on the fuel rail.

Today, after a run from NY to ON, there was raw fuel on the cardboard shield & mostly on the middle cardboard piece & also all along the top of the driver's side of the valve cover. This (to me) means that the spray is going forward & backward & seems to be concentrated around the #3 line.

I'm going on a run from IN to QC, so I wrapped all the line-nuts at the head with cardboard & put a 90 degree cardboard shield over the injector lines. I'm trying to isolate where the leak is coming from.

The ironic part about this is, the engine never misses a beat under high-load conditions & idles smooth & doesn't smoke. You'd think that if it was a cracked or leaking injector line, it would affect something?

Any ideas???

John Good

 

The 03 had a fuel line at one or two injectors that will brake the line check with your dodge place.I had to replace one on my truck hair line brake==Good luck

 

Common rail engines will self bleed if the engine is cranked, no need to crack the lines. You mechanic needs to be educated...

 

Might be what blackbear mentioned,cracked fuel line.If you say its only leaking under high load conditions then what you are saying is when the rail pressure is elevated.One way to check it is to unplug the fca and crank the truck.This will cause the RP to go to max while idling.Only down side to this is it is not good on the injectors to let it run like this for long.If you opt to try this get an extra hand and have them start the truck and you look for a leak at a safe distance! 24kpsi can be very dangerous! I wouldn't let the truck run for more than a couple seconds at a time.Maybe you will get lucky and it will show up immidiately.

 

Just got back from my run from IN to Quebec.

Truck still runs like "Jack the Bear"! BUT... the whole chassis from the engine back to the rear bumper is dripping with diesel fuel & it's coming from the area of the common rail/injector lines.

On Sunday I'll check my cardboard test pieces to try to isolate the leak.

I'm taking it to my buddy's garage on Monday. We'll try "homewrecker's" suggestion CAREFULLY at the garage.

I'll keep you guys posted about what we find. I may end up taking it to the dealer if we can't find the cause of the leak.

John Good

 

Just for sanity, check engine oil level. To be sure you don't have an injector going out and overfilling such that the oil/fuel is being dumped out the draft tube.

Tony

 

You may have to replace the leaky injector line or lines. If one was loose it will etch a grove in the lines due to the high pressure and it will not seal properly again. Good luck to ya.

 

Well, it turned out that mine was leaking from the #2 Injector Line nut where it screws into the Injector Tube at the head.

What we did at the garage was Fred (one of Jack's mechanics) watched while I held the brakes on & slowly raised the RPM's to 1500 & he spotted it right away.

We removed the line to inspect it for cracks or pinholes, by running it under the wire wheel & also Fred hooked up a Vacuum Pump to it. Could'nt find anything so he re-installed the line, with the understanding that if it still leaked, at least we knew which line to order from Cummins.

Test drove it & it seems to be fine now.

Going on a run from IN to Newfoundland tomorrow, so we'll see if anything leaks then.

Cheap fix... So far!!!

John Good

 

Yes I said that the 03 had some trouble with 2 of the injectors lines getting a hair line crack. Dodge people does know about it.If they have some old hand around.They will know witch one's they are.They put a extra brace on the number 3 line.