Cummins Cylinder #4 Fuel Injection Line Crack

If you own a Dodge with a Cummins motor in it long enough, you eventually learn what the photo above is (well, the line is already removed in this photo, see below).  The fuel injector line for cylinder #4 is famous for having it’s support vibrate loose (the blue blocks in the photo above), then the line itself vibrates until it cracks right at the injector (photo below).  It needs to be checked and tightened a couple of times per year.  Of course, having owned this truck less than a year, I didn’t know that.  Lesson learned (at a cost of $75 plus some time).

I was supposed to spend the day working on the plane.  As I was walking through the kitchen on my way out to the shop yesterday, I got a text about a friend in an ambulance on the way to the Emergency Room (long story short, he’s fine).  So off I went into town.  For the last two days, I’ve been smelling diesel whenever I stop at a light.  I kind of ignored it on the way to the hospital, but on the way back, the smell suddenly got much stronger, and there was big clouds of steam coming out from under my hood.  I pulled off the highway onto a side road, then pulled over and lifted the hood.  Well, the steam wasn’t steam.  It was diesel fuel.  Enormous billowing clouds of it.  And it was all spraying out of a tiny crack right at the injector of cylinder #4.  The fuel system on this engine runs about 7000psi at idle up to about 23,000psi at full throttle.  No wonder it made a cloud.  I hustled back to the cab, shut the engine down, and started making phone calls.  Naturally, the injector line is a dealer-only part, and being Sunday, not a dealer in the state seemed to be open.  So the truck was down for the night.  My wife, being as awesome as she is, towed me home with her Tahoe, which she got a great feeling of satisfaction from (towing a broken Dodge with a Chevy).

The good news is that I called the closest dealer at the crack of dawn this morning, and he had exactly one in stock.  He put my name on it, and I drove into town to get it.  Turns out they’ve had so many problems with this that they re-designed the part (see the photo below).  Now, instead of the little blue plastic blocks with the bolt that vibrates loose every six months, there’s a monster chunk of steel with a rubber damper that bolts down in place of the plastic and steel holder.  Looks much more robust.  Here’s the good news:  less than five minutes to pull the old line out, and less than ten to put the new one in.  And the engine fired on the first crank (provided that you bleed the system per the manual first, which basically amounts to letting the fuel pump run for 20 seconds before cranking).

And there’s the new injector line in it’s new home.

So another weekend with no progress made on the plane.  Bah humbug.

 

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